注塑模具毕业设计外文翻译
塑料注塑模具中英文对照外文翻译文献
外文翻译及原文(文档含英文原文和中文翻译)【原文一】CONCURRENT DESIGN OF PLASTICS INJECTION MOULDS AbstractThe plastic product manufacturing industry has been growing rapidly in recent years. One of the most popular processes for making plastic parts is injection moulding. The design of injection mould is critically important to product quality and efficient product processing.Mould-making companies, who wish to maintain the competitive edge, desire to shorten both design and manufacturing leading times of the by applying a systematic mould design process. The mould industry is an important support industry during the product development process, serving as an important link between the product designer and manufacturer. Product development has changed from the traditional serial process of design, followed by manufacture, to a more organized concurrent process where design and manufacture are considered at a very early stage of design. The concept of concurrent engineering (CE) is no longer new and yet it is still applicable and relevant in today’s manuf acturing environment. Team working spirit, management involvement, total design process and integration of IT tools are still the essence of CE. The application of The CE process to the design of an injection process involves the simultaneous consideration of plastic part design, mould design and injection moulding machine selection, production scheduling and cost as early as possible in the design stage.This paper presents the basic structure of an injection mould design. The basis of this system arises from an analysis of the injection mould design process for mould design companies. This injection mould design system covers both the mould design process and mould knowledge management. Finally the principle of concurrent engineering process is outlined and then its principle is applied to the design of a plastic injection mould.Keywords :Plastic injection mould design, Concurrent engineering, Computer aided engineering, Moulding conditions, Plastic injection moulding, Flow simulation1.IntroductionInjection moulds are always expensive to make, unfortunately without a mould it can not be possible ho have a moulded product. Every mould maker has his/her own approach to design a mould and there are many different ways of designing and building a mould. Surely one of the most critical parameters to be considered in the design stage of the mould is the number of cavities, methods of injection, types of runners, methods of gating, methods of ejection, capacity and features of the injection moulding machines. Mould cost, mould quality and cost of mould product are inseparableIn today’s completive environment, computer aided mould filling simulation packages can accurately predict the fill patterns of any part. This allows for quick simulations of gate placements and helps finding the optimal location. Engineers can perform moulding trials on the computer before the part design is completed. Process engineers can systematically predict a design and process window, and can obtain information about the cumulative effect of the process variables that influence part performance, cost, and appearance.2.Injection MouldingInjection moulding is one of the most effective ways to bring out the best in plastics. It is universally used to make complex, finished parts, often in a single step, economically, precisely and with little waste. Mass production of plastic parts mostly utilizes moulds. The manufacturing process and involving moulds must be designed after passing through the appearance evaluation and the structure optimization of the product design. Designers face a hugenumber of options when they create injection-moulded components. Concurrent engineering requires an engineer to consider the manufacturing process of the designed product in the development phase. A good design of the product is unable to go to the market if its manufacturing process is impossible or too expensive. Integration of process simulation, rapid prototyping and manufacturing can reduce the risk associated with moving from CAD to CAM and further enhance the validity of the product development.3. Importance of Computer Aided Injection Mould DesignThe injection moulding design task can be highly complex. Computer Aided Engineering (CAE) analysis tools provide enormous advantages of enabling design engineers to consider virtually and part, mould and injection parameters without the real use of any manufacturing and time. The possibility of trying alternative designs or concepts on the computer screen gives the engineers the opportunity to eliminate potential problems before beginning the real production. Moreover, in virtual environment, designers can quickly and easily asses the sensitivity of specific moulding parameters on the quality and manufacturability of the final product. All theseCAE tools enable all these analysis to be completed in a meter of days or even hours, rather than weeks or months needed for the real experimental trial and error cycles. As CAE is used in the early design of part, mould and moulding parameters, the cost savings are substantial not only because of best functioning part and time savings but also the shortens the time needed to launch the product to the market.The need to meet set tolerances of plastic part ties in to all aspects of the moulding process, including part size and shape, resin chemical structure, the fillers used, mould cavity layout, gating, mould cooling and the release mechanisms used. Given this complexity, designers often use computer design tools, such as finite element analysis (FEA) and mould filling analysis (MFA), to reduce development time and cost. FEA determines strain, stress and deflection in a part by dividing the structure into small elements where these parameters can be well defined. MFA evaluates gate position and size to optimize resin flow. It also defines placement of weld lines, areas of excessive stress, and how wall and rib thickness affect flow. Other finite element design tools include mould cooling analysis for temperature distribution, and cycle time and shrinkage analysis for dimensional control and prediction of frozen stress and warpage.The CAE analysis of compression moulded parts is shown in Figure 1. The analysis cycle starts with the creation of a CAD model and a finite element mesh of the mould cavity. After the injection conditions are specified, mould filling, fiber orientation, curing and thermal history, shrinkage and warpage can be simulated. The material properties calculated by the simulation can be used to model the structural behaviour of the part. If required, part design, gate location and processing conditions can be modified in the computer until an acceptable part is obtained. After the analysis is finished an optimized part can be produced with reduced weldline (known also knitline), optimized strength, controlled temperatures and curing, minimized shrinkage and warpage.Machining of the moulds was formerly done manually, with a toolmaker checking each cut. This process became more automated with the growth and widespread use of computer numerically controlled or CNC machining centres. Setup time has also been significantly reduced through the use of special software capable of generating cutter paths directly from a CAD data file. Spindle speeds as high as 100,000 rpm provide further advances in high speed machining. Cutting materials have demonstrated phenomenal performance without the use of any cutting/coolant fluid whatsoever. As a result, the process of machining complex cores and cavities has been accelerated. It is good news that the time it takes to generate a mould is constantly being reduced. The bad news, on the other hand, is that even with all these advances, designing and manufacturing of the mould can still take a long time and can be extremely expensive.Figure 1 CAE analysis of injection moulded partsMany company executives now realize how vital it is to deploy new products to market rapidly. New products are the key to corporate prosperity. They drive corporate revenues, market shares, bottom lines and share prices. A company able to launch good quality products with reasonable prices ahead of their competition not only realizes 100% of the market before rival products arrive but also tends to maintain a dominant position for a few years even after competitive products have finally been announced (Smith, 1991). For most products, these two advantages are dramatic. Rapid product development is now a key aspect of competitive success. Figure 2 shows that only 3–7% of the product mix from the average industrial or electronics company is less than 5 years old. For companies in the top quartile, the number increases to 15–25%. For world-class firms, it is 60–80% (Thompson, 1996). The best companies continuously develop new products. AtHewlett-Packard, over 80% of the profits result from products less than 2 years old! (Neel, 1997)Figure 2. Importance of new product (Jacobs, 2000)With the advances in computer technology and artificial intelligence, efforts have been directed to reduce the cost and lead time in the design and manufacture of an injection mould. Injection mould design has been the main area of interest since it is a complex process involving several sub-designs related to various components of the mould, each requiring expert knowledge and experience. Lee et. al. (1997) proposed a systematic methodology and knowledge base for injection mould design in a concurrent engineering environment.4.Concurrent Engineering in Mould DesignConcurrent Engineering (CE) is a systematic approach to integrated product development process. It represents team values of co-operation, trust and sharing in such a manner that decision making is by consensus, involving all per spectives in parallel, from the very beginning of the productlife-cycle (Evans, 1998). Essentially, CE provides a collaborative, co-operative, collective and simultaneous engineering working environment. A concurrent engineering approach is based on five key elements:1. process2. multidisciplinary team3. integrated design model4. facility5. software infrastructureFigure 3 Methodologies in plastic injection mould design, a) Serial engineering b) Concurrent engineeringIn the plastics and mould industry, CE is very important due to the high cost tooling and long lead times. Typically, CE is utilized by manufacturing prototype tooling early in the design phase to analyze and adjust the design. Production tooling is manufactured as the final step. The manufacturing process and involving moulds must be designed after passing through the appearance evaluation and the structure optimization of the product design. CE requires an engineer to consider the manufacturing process of the designed product in the development phase.A good design of the product is unable to go to the market if its manufacturing process is impossible. Integration of process simulation and rapid prototyping and manufacturing can reduce the risk associated with moving from CAD to CAM and further enhance the validity of the product development.For years, designers have been restricted in what they can produce as they generally have todesign for manufacture (DFM) – that is, adjust their design intent to enable the component (or assembly) to be manufactured using a particular process or processes. In addition, if a mould is used to produce an item, there are therefore automatically inherent restrictions to the design imposed at the very beginning. Taking injection moulding as an example, in order to process a component successfully, at a minimum, the following design elements need to be taken into account:1. . geometry;. draft angles,. Non re-entrants shapes,. near constant wall thickness,. complexity,. split line location, and. surface finish,2. material choice;3. rationalisation of components (reducing assemblies);4. cost.In injection moulding, the manufacture of the mould to produce the injection-moulded components is usually the longest part of the product development process. When utilising rapid modelling, the CAD takes the longer time and therefore becomes the bottleneck.The process design and injection moulding of plastics involves rather complicated and time consuming activities including part design, mould design, injection moulding machine selection, production scheduling, tooling and cost estimation. Traditionally all these activities are done by part designers and mould making personnel in a sequential manner after completing injection moulded plastic part design. Obviously these sequential stages could lead to long product development time. However with the implementation of concurrent engineering process in the all parameters effecting product design, mould design, machine selection, production scheduling,tooling and processing cost are considered as early as possible in the design of the plastic part. When used effectively, CAE methods provide enormous cost and time savings for the part design and manufacturing. These tools allow engineers to virtually test how the part will be processed and how it performs during its normal operating life. The material supplier, designer, moulder and manufacturer should apply these tools concurrently early in the design stage of the plastic parts in order to exploit the cost benefit of CAE. CAE makes it possible to replace traditional, sequential decision-making procedures with a concurrent design process, in which all parties can interact and share information, Figure 3. For plastic injection moulding, CAE and related design data provide an integrated environment that facilitates concurrent engineering for the design and manufacture of the part and mould, as well as material selection and simulation of optimal process control parameters.Qualitative expense comparison associated with the part design changes is shown in Figure 4 , showing the fact that when design changes are done at an early stages on the computer screen, the cost associated with is an order of 10.000 times lower than that if the part is in production. These modifications in plastic parts could arise fr om mould modifications, such as gate location, thickness changes, production delays, quality costs, machine setup times, or design change in plastic parts.Figure 4 Cost of design changes during part product development cycle (Rios et.al, 2001)At the early design stage, part designers and moulders have to finalise part design based on their experiences with similar parts. However as the parts become more complex, it gets rather difficult to predict processing and part performance without the use of CAE tools. Thus for even relatively complex parts, the use of CAE tools to prevent the late and expensive design changesand problems that can arise during and after injection. For the successful implementation of concurrent engineering, there must be buy-in from everyone involved.5.Case StudyFigure 5 shows the initial CAD design of plastics part used for the sprinkler irrigation hydrant leg. One of the essential features of the part is that the part has to remain flat after injection; any warping during the injection causes operating problems.Another important feature the plastic part has to have is a high bending stiffness. A number of feeders in different orientation were added to the part as shown in Figure 5b. These feeders should be designed in a way that it has to contribute the weight of the part as minimum aspossible.Before the design of the mould, the flow analysis of the plastic part was carried out with Moldflow software to enable the selection of the best gate location Figure 6a. The figure indicates that the best point for the gate location is the middle feeder at the centre of the part. As the distortion and warpage of the part after injection was vital from the functionality point of view and it has to be kept at a minimum level, the same software was also utilised to yiled the warpage analysis. Figure 5 b shows the results implying the fact that the warpage well after injection remains within the predefined dimensional tolerances.6. ConclusionsIn the plastic injection moulding, the CAD model of the plastic part obtained from commercial 3D programs could be used for the part performance and injection process analyses. With the aid ofCEA technology and the use of concurrent engineering methodology, not only the injection mould can be designed and manufactured in a very short of period of time with a minimised cost but also all potential problems which may arise from part design, mould design and processing parameters could be eliminated at the very beginning of the mould design. These two tools help part designers and mould makers to develop a good product with a better delivery and faster tooling with less time and money.References1. Smith P, Reinertsen D, The time-to-market race, In: Developing Products in Half the Time. New York, Van Nostrand Reinhold, pp. 3–13, 19912.Thompson J, The total product development organization. Proceedings of the SecondAsia–Pacific Rapid Product Development Conference, Brisbane, 19963.Neel R, Don’t stop after the prototype, Seventh International Conference on Rapid Prototyping, San Francisco, 19974.Jacobs PF, “Chapter 3: Rapid Product Development” in Rapid Tooling: Technologies and Industrial Applications , Ed. Peter D. Hilton; Paul F. Jacobs, Marcel Decker, 20005.Lee R-S, Chen, Y-M, and Lee, C-Z, “Development of a concurrent mould design system: a knowledge based approach”, Computer Integrated Manufacturing Systems, 10(4), 287-307, 19976.Evans B., “Simultaneous Engineering”, Mechanical Engi neering , V ol.110, No.2, pp.38-39, 19987.Rios A, Gramann, PJ and Davis B, “Computer Aided Engineering in Compression Molding”, Composites Fabricators Association Annual Conference , Tampa Bay, 2001【译文一】塑料注塑模具并行设计塑料制品制造业近年迅速成长。
模具毕业设计外文翻译(英文+译文)
Injection MoldingThe basic concept of injection molding revolves around the ability of a thermoplastic material to be softened by heat and to harden when cooled .In most operations ,granular material (the plastic resin) is fed into one end of the cylinder (usually through a feeding device known as a hopper ),heated, and softened(plasticized or plasticized),forced out the other end of the cylinder, while it is still in the form of a melt, through a nozzle into a relatively cool mold held closed under pressure.Here,the melt cools and hardens until fully set-up. The mold is then opened, the piece ejected, and the sequence repeated.Thus, the significant elements of an injection molding machine become: 1) the way in which the melt is plasticized (softened) and forced into the mold (called the injection unit);2) the system for opening the mold and closing it under pressure (called the clamping unit);3) the type of mold used;4) the machine controls.The part of an injection-molding machine, which converts a plastic material from a sold phase to homogeneous seni-liguid phase by raising its temperature .This unit maintains the material at a present temperature and force it through the injection unit nozzle into a mold .The plunger is a combination of the injection and plasticizing device in which a heating chamber is mounted between the plunger and mold. This chamber heats the plastic material by conduction .The plunger, on each stroke; pushes unbelted plastic material into the chamber, which in turn forces plastic melt at the front of the chamber out through the nozzleThe part of an injection molding machine in which the mold is mounted, and which provides the motion and force to open and close the mold and to hold the mold close with force during injection .This unit can also provide other features necessary for the effective functioning of the molding operation .Movingplate is the member of the clamping unit, which is moved toward a stationary member. the moving section of the mold is bolted to this moving plate .This member usually includes the ejector holes and mold mounting pattern of blot holes or “T” slots .Stationary plate is the fixed member of the clamping unit on which the stationary section of the mold is bolted .This member usually includes a mold-mounting pattern of boles or “T” slots. Tie rods are member of the clamping force actuating mechanism that serve as the tension member of the clamp when it is holding the mold closed. They also serve as a gutted member for the movable plate .Ejector is a provision in the clamping unit that actuates a mechanism within the mold to eject the molded part(s) from the mold .The ejection actuating force may be applied hydraulically or pneumatically by a cylinder(s) attached to the moving plate, or mechanically by the opening stroke of the moving plate.Methods of melting and injecting the plastic differ from one machine to another and are constantly being implored .conventional machines use a cylinder and piston to do both jobs .This method simplifies machine construction but makes control of injection temperatures and pressures an inherently difficult problem .Other machines use a plasticizing extruder to melt the plastic and piston to inject it while some hare been designed to use a screw for both jobs :Nowadays, sixty percent of the machines use a reciprocating screw,35% a plunger (concentrated in the smaller machine size),and 5%a screw pot.Many of the problems connected with in ejection molding arise because the densities of polymers change so markedly with temperature and pressure. thigh temperatures, the density of a polymer is considerably cower than at room temperature, provided the pressure is the same.Therefore,if molds were filled at atmospheric pressure, “shrinkage” would make the molding deviate form the shape of the mold.To compensate for this poor effect, molds are filled at high pressure. The pressure compresses the polymer and allows more materials to flow into the mold, shrinkage is reduced and better quality moldings are produced.Cludes a mold-mounting pattern of bolt holes or “T” slots. Tie rods are members of the clamping force actuating mechanism that serve as the tension members of clamp when it is holding the mold closed. Ejector is a provision in the calming unit that actuates a mechanism within the mold to eject the molded part(s) form the mold. The ejection actuating force may be applied hydraulically or pneumatically by a cylinder(s) attached to the moving plate, or mechanically by the opening stroke of the moving plate.The function of a mold is twofold: imparting the desired shape to the plasticized polymer and cooling the injection molded part. It is basically made up of two sets of components: the cavities and cores and the base in which the cavities and cores are mounted. The mold ,which contains one or more cavities, consists of two basic parts :(1) a stationary molds half one the side where the plastic is injected,(2)Moving half on the closing or ejector side of the machine. The separation between the two mold halves is called the parting line. In some cases the cavity is partly in the stationary and partly in the moving section. The size and weight of the molded parts limit the number of cavities in the mold and also determine the machinery capacity required. The mold components and their functions are as following:(1)Mold Base-Hold cavity (cavities) in fixed, correctposition relative to machine nozzle.(2)Guide Pins-Maintain Proper alignment of entry into moldinterior.(3)Spree Bushing (spree)-Provide means of entry into moldinterior.(4)Runners-Conroy molten plastic from spree to cavities.(5)Gates-Control flow into cavities.(6)Cavity (female) and Force (male)-Control the size,shape and surface of mold article.(7)Water Channels-Control the temperature of mold surfacesto chill plastic to rigid state.(8)Side (actuated by came, gears or hydrauliccylinders)-Form side holes, slots, undercuts and threaded sections.(9)Vent-Allow the escape of trapped air and gas.(10)Ejector Mechanism (pins, blades, stripper plate)-Ejectrigid molded article form cavity or force.(11)Ejector Return Pins-Return ejector pins to retractedposition as mold closes for next cycle.The distance between the outer cavities and the primary spree must not be so long that the molten plastic loses too much heat in the runner to fill the outer cavities properly. The cavities should be so arranged around the primary spree that each receives its full and equal share of the total pressure available, through its own runner system (or the so-called balanced runner system).The requires the shortest possible distance between cavities and primary sprue, equal runner and gate dimension, and uniform culling.注射成型注射成型的基本概念是使热塑性材料在受热时熔融，冷却时硬化，在大部分加工中，粒状材料（即塑料树脂）从料筒的一端（通常通过一个叫做“料斗”的进料装置）送进，受热并熔融（即塑化或增塑），然后当材料还是溶体时，通过一个喷嘴从料筒的另一端挤到一个相对较冷的压和封闭的模子里。
机械设计毕业设计外文文献翻译中英文对照塑料模具CAD集成技术
机械设计毕业设计外文文献翻译中英文对照：塑料模具CAD集成技术毕业设计外文文献翻译毕业设计题目摇控器面板注塑模设计翻译题目The molding tool CAD gathers the technique专业机械设计制造及其自动化姓名班级机械A0731学号指导教师机械与材料工程学院二O一O年十一月[K.P. Rao and K. Sivaram: J. Mater. Proc. Technol., 1993, vol. 37, pp.295-318.]毕业论文(设计)外文翻译课题名称:塑料模具CAD集成技术内容提要:通过分析计算机辅助注射模设计和制造的各个环节中共享的技术和信息,本文揭示了注射模CAD的集成技术的根本内涵,并提出了它的研究热点和趋势。
引言模具CAD集成技术是一项重要的模具先进制造技术, 是一项用高技术改造模具传统技术的重要关键技术。
从六五计划开始,我国有许多模具企业采用CAD 技术, 特别是近年, CAD技术的应用越来越普遍和深入, 大大缩短了模具设计周期,提高了制模质量和复杂模具的制造能力。
然而, 由于许多企业对模具CAD集成技术认识不足, 投资带有盲目性, 不能很好地发挥作用,造成了很大的浪费。
本文就塑料模具CAD集成技术及其应用发表一些观点, 供大家参考。
1、塑料模具CAD集成技术塑料模具的制造, 包括塑料产品的造型设计、模具的结构设计及分析、模具的数控加工铣削、电加工、线切割等、抛光和配试模以及快速成形制造等。
各个环节所涉及的CAD单元技术有:造型和结构设计CAD、产品外形的快速反求RE、结构分析与优化设计CAE、辅助制造CAM、加工过程虚拟仿真SIMULATION、产品及模具的快速成形RP、辅助工艺过程CAPP和产品数据管理技术PDM等。
塑料模具CAD集成技术,? 就是把塑料模具制造过程所涉及的各项单元技术集成起来, 统一数据库和文件传输格式, 实现信息集成和数据资源共享, 从而大大缩短模具的设计制造周期, 提高制模质量。
注塑模具设计外文翻译
毕业设计（论文）外文资料翻译及原文（2012届）题目电话机三维造型与注塑模具设计指导教师院系工学院班级学号姓名二〇一一年十二月六日【译文一】塑料注塑模具并行设计Assist.Prof.Dr. A. Y AYLA /Prof.Dr. Paş a YAYLA摘要塑料制品制造业近年迅速成长。
其中最受欢迎的制作过程是注塑塑料零件。
注塑模具的设计对产品质量和效率的产品加工非常重要。
模具公司想保持竞争优势,就必须缩短模具设计和制造的周期。
模具是工业的一个重要支持行业，在产品开发过程中作为一个重要产品设计师和制造商之间的联系。
产品开发经历了从传统的串行开发设计制造到有组织的并行设计和制造过程中,被认为是在非常早期的阶段的设计。
并行工程的概念(CE)不再是新的,但它仍然是适用于当今的相关环境。
团队合作精神、管理参与、总体设计过程和整合IT工具仍然是并行工程的本质。
CE过程的应用设计的注射过程包括同时考虑塑件设计、模具设计和注塑成型机的选择、生产调度和成本中尽快设计阶段。
介绍了注射模具的基本结构设计。
在该系统的基础上,模具设计公司分析注塑模具设计过程。
该注射模设计系统包括模具设计过程及模具知识管理。
最后的原则概述了塑料注射模并行工程过程并对其原理应用到设计。
关键词:塑料注射模设计、并行工程、计算机辅助工程、成型条件、塑料注塑、流动模拟1、简介注塑模具总是昂贵的,不幸的是没有模具就不可能生产模具制品。
每一个模具制造商都有他/她自己的方法来设计模具,有许多不同的设计与建造模具。
当然最关键的参数之一,要考虑到模具设计阶段是大量的计算、注射的方法,浇注的的方法、研究注射成型机容量和特点。
模具的成本、模具的质量和制件质量是分不开的在针对今天的计算机辅助充型模拟软件包能准确地预测任何部分充填模式环境中。
这允许快速模拟实习,帮助找到模具的最佳位置。
工程师可以在电脑上执行成型试验前完成零件设计。
工程师可以预测过程系统设计和加工窗口,并能获得信息累积所带来的影响,如部分过程变量影响性能、成本、外观等。
注塑成型的模具设计外文翻译
Figure 1. Organization of the IKEM Project2 Intelligent Mold Design ToolThe mold design tool in its basic form is a Visual Basic application taking input from a text file that contains information about the part and a User Input form. The text file contains information about the part geometry parsed from a Pro/E information file. The input is used to estimate the dimensions of mold and various other features.2.1 Literature ReviewDesign of molds is another stage of the injection molding process where the experience of an engineer largely helps automate the process and increase its efficiency. The issue that needs attention is the time that goes into designing the molds. Often, design engineers refer to tables and standard handbooks while designing a mold, which consumes lot of time. Also, a great deal of time goes into modeling components of the mold in standard CAD software. Differentresearchers have dealt with the issue of reducing the time it takes to design the mold in different ways. Koelsch and James have employed group technology techniques to reduce the mold design time. A unique coding system that groups a class of injection molded parts, and the tooling required ininjection molding is developed which is general and can be applied to other product lines.A software system to implement the coding system has also been developed. Attempts were also directed towards the automation of the mold design process by capturing experience and knowledge of engineers in the field. The development of a concurrent mold design system is one such approach that attempts to develop a systematic methodology for injection mold design processes in a concurrent engineering environment. The objective of their research was to develop a mold development process that facilitates concurrent engineering-based practice, andFigure 2. Organization of the Mold Design Module.While most of the input, like the number of cavities, cavity image dimensions, cycle time are based on the client specifications, other input like the plasticizing capacity, shots per minute etc., can be obtained from the machine specifications. The output of the application contains mold dimensions and other information, which clearly helps in selecting the standard mold base from catalogs. Apart from the input and output, the Figure 2 also shows the various modules that produce the final output.2.5 Framing rulesAt this stage, the expert’s knowledge is represented in the form of multiple If-Then statements. The rules may be representations of both qualitative and quantitative knowledge. By qualitative knowledge, we mean deterministic information about a problem that can be solved computationally. By qualitative we mean information that is not deterministic, but merely followed as a rule based on previous cases where the rule has worked. A typical rule is illustrated below:If Material = “Acetal” AndRunner Length <= 3 AndRunner Length > 0 ThenRunner Diameter =0.062End IfWhen framing the rules it is important that we represent the information in a compact way while avoiding redundancy, incompleteness and inconsistency. Decision tables help take care of all the above concerns by checking for redundancy and comprehensive expression of the problem statement. As an example, in the process of selecting an appropriate mold base, the size of mold base depends on the number of cavities and inserts. To ensure that all possible combinations of。
注塑模具毕业设计方案外文翻译样本
注塑模具毕业设计方案外文翻译附录外文资料与中文翻译外文资料：China's mold industry and its development trendThe mold is the manufacturing industry important craft foundation, in our country, the mold manufacture belongs to the special purpose equipment manufacturing industry. China although very already starts to make the mold and the use mold, but long-term has not formed the industry. Straight stabs 0 centuries 80's later periods, the Chinese mold industry only then drives into the development speedway. Recent years, not only the state-owned mold enterprise had the very big development, the three investments enterprise, the villages and towns (individual) the mold enterprise's development also quite rapid .Although the Chinese mold industrial development rapid, but compares with the demand, obviously falls short of demand, itsmain gap concentrates precisely to, large-scale,complex, the long life mold domain. As a result of in aspect and so on mold precision, life, manufacture cycle and productivity, China and the international average horizontal and the developed country still had a bigger disparity, therefore, needed massively to import the mold every year .The Chinese mold industry except must continue to sharpen the productivity, from now on will have emphatically to the profession internal structure adjustment and the state-of-art enhancement. The structure adjustment aspect, mainly is the enterprise structure to the specialized adjustment, the product structure to center the upscale mold development, to the import and export structure improvement, center the upscale automobile cover mold forming analysis and the structure improvement, the multi-purpose compound mold and thecompound processing and the laser technology in the mold design manufacture application, the high-speed cutting, the superfinishing and polished the technology, the information direction develops .The recent years, the mold profession structure adjustment and the organizational reform step enlarges, mainly displayed in, large-scale, precise, complex, the long life, center the upscale mold and the mold standard letter development speed is higher than the common mold product; The plastic mold and the compression casting mold proportion increases; Specialized mold factory quantity and its productivity increase; "The three investments" and the private enterprise develops rapidly; The joint stock system transformation step speeds up and so on. Distributes from the area looked, take Zhujiang Delta and Yangtze River delta as central southeast coastal area development quickly to mid-west area,south development quickly to north. At present develops quickest, the mold produces the most centralized province is Guangdong and Zhejiang, places such as Jiangsu, Shanghai, Anhui and Shandong also has a bigger development in recent years .Although our country mold total quantity had at present achieved the suitable scale, the mold level also has the very big enhancement, after but design manufacture horizontal overall rise and fall industry developed country and so on Yu De, America, date, France, Italy many. The current existence question and the disparity mainly display in following several aspects:(1) The total quantity falls short of demandDomestic mold assembling oneself rate only ,about 70%. Low-grade mold , center upscale mold assembling oneself rate only has 50% about .(2) The enterprise organizational structure, the product structure, the technical structure and the import and export structure does not gatherIn our country mold production factory to be most is from the labor mold workshop which produces assembles oneself (branch factory), from produces assembles oneself the proportion to reach as high as about 60%, but the overseas mold ultra 70% is the commodity mold. The specialized mold factory mostly is "large and complete", "small and entire" organization form, but overseas mostly is "small but", "is specially small and fine". Domestic large-scale, precise, complex, the long life mold accounts for the total quantity proportion to be insufficient 30%, but overseas in 50% above 2004 years, ratio of the mold import and export is :1, the import and export balances the after net import volume to amount to billion US dollars, isworld mold net import quantity biggest country .(3) The mold product level greatly is lower than the international standard The production cycle actually is higher than the international water broad product level low mainly to display in the mold precision, cavity aspect and so on surface roughness, life and structure .(4) Develops the ability badly, economic efficiency country mold enterprise technical personnel proportion low the level is lower, also does not take the product development, frequently is in the passive position in the market. Our country each mold staff average year creation output value approximately ,ten thousand US dollars, overseas mold industry developed country mostly 15 to 20 thousand US dollars, some reach as high as 25 to 30 thousand US dollars, relative is our country quite part of molds enterprises alsocontinues to use the workshop type management with it, truly realizes the enterprise which the modernized enterprise manages fewTo create the above disparity the reason to be very many, the mold long-term has not obtained the value besides the history in as the product which should have, as well as the most state-owned enterprises mechanism cannot adapt the market economy, but also has the following several reasons: .(1) Country to mold industry policy support dynamics also insufficiently Although the country already was clear about has promulgated the mold profession industrial policy, but necessary policy few, carried out dynamics to be weak. At present enjoyed the mold product increment duty enterprise nation 185, the majority enterprise still the tax burden is only overweight. The mold enterprise carries on the technological transformationsintroduction equipment to have to pay the considerable amount the tax money, affects the technology advancement, moreover privately operated enterprise loan extremely difficult .(2) Talented person serious insufficient, the scientific research development and the technical attack investment too urineMold profession is the technology, the fund, the work crowded industry, along with the time progress and the technical development, grasps the talented person which and skilled utilizes the new technology exceptionally short, the high-quality mold fitter and the enterprise management talent extremely is also anxious. Because the mold enterprise benefit unsatisfactory and takes insufficiently the scientific research development and the technical attack, the scientific research unit and the universities, colleges andinstitutes eye stares at is creating income, causes the mold profession invests too few in the scientific research development and the technical attack aspect, causes the mold technological development step not to be big, progresses not quick .(3) The craft equipment level to be low, also necessary is not good, the use factor lowrecent years our country engine bed profession progressed quickly, has been able to provide the quite complete precision work equipment, but compared with the overseas equipment, still had a bigger disparity. Although the domestic many enterprises have introduced many overseas advanced equipment, but the overall equipment level low are very more than the overseas many enterprises. As a result of aspect the and so on system and fund reason, introduces the equipment not not necessary, the equipment and the appendix not necessaryphenomenon are extremely common, the equipment utilization rate low question cannot obtain the comparatively properly solution for a long time .(4) Specialization, standardization, commercialized degree low, the cooperation abilityBecause receives "large and complete" "small and entire" the influence since long ago, mold specialization level low, the specialized labor division is not careful, the commercialized degree is low. At present domestic every year produces mold, commodity mold minister 40% About, other for from produce uses for oneself. Between the mold enterprise cooperates impeded, completes the comparatively large-scale mold complete task with difficulty. Mold standardization level low, mold standard letter use cave rare is low also to the mold quality, the cost has a more tremendousinfluence, specially has very tremendous influence .(5) To the mold manufacture cycle) the mold material and the mold correlation technology fallsThe mold material performance, the quality and the variety question often can affect the mold quality, the life and the cost, the domestically produced molding tool steel and overseas imports the steel products to compare has a bigger disparity. Plastic, plate, equipment energy balance, also direct influence mold level enhancement .At present, our country economy still was at the high speed development phase, on the international economical globalization development tendency is day by day obvious, this has provided the good condition and the opportunity for the our country mold industry high speed development. On the one hand, the domestic mold market will continuehigh speed to develop, on the other hand, the mold manufacture also gradually will shift as well as the transnational group to our country carries on the mold purchase trend to our country extremely to be also obvious. Therefore, will take a broad view the future, international, the domestic mold market overall development tendency prospect will favor, estimated the Chinese mold will obtain the high speed development under the good market environment, our country not only can become the mold great nation, moreover certainly gradually will make the powerful nation to the mold the ranks to make great strides forward. "15" period, the Chinese mold industry level not only has the very big enhancement in the quantity and the archery target aspect, moreover the profession structure, the product level, the development innovation ability, enterprise's system and the mechanism aswell as the technology advancement aspect also can obtain a bigger development .The mold technology has gathered the machinery, the electron, chemistry, optics, the material, the computer, the precise monitor and the information network and so on many disciplines, is a comprehensive nature multi-disciplinary systems engineering. The mold technology development tendency mainly is the mold product to larger-scale, preciser, more complex and a more economical direction develops, the mold product technical content unceasingly enhances, the mold manufacture cycle unceasingly reduces, the mold production faces the information, is not having the chart, is fine, the automated direction develops, the mold enterprise to the technical integration, the equipment excellent, is producing approves the brand, the management information, the management internationalization direction develops.Our country mold profession still will have to enhance from now on the general character technology had :(1) To establish in the CAD/CAE platform the advanced mold design technology, enhances modernization which the mold designed, information, intellectualization, standardized level .(2) Establishes in the CAM/CAPP foundation the advanced mold processing technology and the advanced manufacture technology unifies, raises the automated level and the production efficiency which the mold processes .(3) The mold production enterprise's information management technology. For example PDM (product data management), ERP (enterprise resource management), MIS (mold manufacture management information system) and information network technology the and so on INTERMET platform application, the promotion and the development .(4) Are high speed, Gao Jing, the compound mold processing technology research and the application. For example the ultra fine ramming mold manufacture technology, the precise plastic and the compression casting mold manufacture technology and so on .(5) Enhances the mold production efficiency, reduces the cost and reduces the mold production cycle each kind of fast economical mold manufacture technology .(6) The advanced manufacture technology application. For example hot technology and so on flow channel technology, gas auxiliary technology, hypothesized technology, nanotechnology, rapid scanning technology, reversion project, parallel project in the mold research, the development, the processing process application .(7) The raw material the simulation technology which forms in the mold .(8) The advanced mold processing and the appropriation equipment research and the development .(9) The mold and the mold standardletter, the important auxiliary standardized technology .(10) The mold and its the product examination technology.(11) High quality, the new mold materialresearch and the development and its thecorrect application .(12) The mold production enterprise'smodern management technology □Mold profession in "十15" period needsto solve the key essential technology shouldbe the mold information, the digitized technology and precise, ultra fine, highspeed, the highly effective manufacture technology aspect breakthrough Along with the national economy totalquantity and the industry product technology unceasing development, all thevarious trades and occupations to the mold demand quantity more and more big, the specification more and more is also high.Although mold type many, but its development should be with emphasis both can meet the massive needs, and has the comparatively high-tech content, specially at present domestic still could not be self-sufficient, needs the massive imports the mold and can represent the development direction large-scale, precise, is complex, the long life mold. The mold standard letter type, the quantity, the level, the production a and so on have the significant influence to the entire mold profession development. Therefore, some important mold standard letters also must the prioritize, moreover its development speed should quickly to the mold development speed, like this be able unceasingly to raise our country mold standardization level, thus improves the mold quality, reduces the moldproduction cycle, reduces the cost. Because our country mold product holds the bigger price superiority in the international market, therefore regarding the exportation prospect good mold product also should take key develops. According to the above required quantity big, the technical content is high, represents the development direction, the export prospect good principle choice prioritize product, moreover chooses the product to have at present to have the certain technology base, belongs has the condition, has the product which the possibility develops .According to "十15" the mold profession development plan, "十15" the period mold product development mainly has following several kind of the automobile cover mold(1)Ramming mold to occupyThe mold total quantity dish with emphasis above 40%. Automobile cover mold mainly for automobile necessary, alsoincludes for the agriculture with the vehicle, the project machinery and the farm machinery necessary cover mold, it has the very big representation in the ramming mold, the mold mostly is large and middle scale, structure complex, the specification is high. For the passenger vehicle necessary cover mold, the request is in particular higher, may represent the ramming mold the level. This kind of mold our country had the certain technology base, already for middle-grade passenger vehicle necessary, but the level is not high, the ability is insufficient, at present satisfying rate only has one about the half. Center the upscale passenger vehicle cover mold main dependence import, has become the bottleneck which the automobile develops, enormous influence vehicle type development .(2)The precise ramming moldMulti- locations level was entering the mold and fine represents the ramming mold development direction, the precision request life request has been extremely high, mainly for the electronics industry, the automobile, the instrument measuring appliance, the electrical machinery electric appliance and so on formed a complete set. These two kind of molds, domestic had the suitable foundation, and has introduced the overseas technology and the equipment, the individual enterprise produces the product has achieved the world level, but the majority of enterprises still had a bigger disparity, the supply total quantity insufficient, the import were very many(3) The large-scale precise plastic moldPlastic mold accounts for the mold total quantity 10%, moreover this proportion also is rising. In the plasticmold necessary large-scale casts the mold for the automobile and the electrical appliances, necessary models for the integrated circuit seals the mold, for the electronic information industry and the machinery and the packing necessary multilayer, the multi- cavities, the multi- material qualities, the multicolor precise note , and saves water the agricultural necessary plastic different molding for the new building materials to squeeze out the mold and the pipeline and the nozzle mold and so on, at present although had the suitable technology base and fast is developing, but the technical level and overseas still had a bigger disparity, the total quantity falls short of demand, Every year import amount reaches several hundred million US dollar.(4) The main mold standard to imitateeAt present domestically to have an greater output the mold standard letter mainly is the mold frame, the guidance, thethrowout lever pushes the tube, the elastic part and so on. These products not only the domestic necessary massive need, the exportation prospect very is also good, should continue vigorously to develop. The nitrogen cylinder and the hot flow channel part main dependence import, should raise the level in the existing foundation, forms the standard and organization scale production.(5) The other high-tech content moldsOccupiesin the mold total quantity green 8% compression casting mold, large-scale thin wall precise compression casting technology content high, the difficulty is big. The magnesium alloy compression casting mold at present although just started, but the prospects for development were good, have the representation. The meridian rubber tire mold also is the development direction, detachable mold technology difficulty isbiggest. With fast takes shape some fast pattern making technologies and the corresponding fast economical mold which the technology unifies has the very good prospects for development. These high-tech content molds in "十15" period also should the prioritize .中文翻译：我国模具工业现状及发展趋势模具是制造业的重要工艺基础，在我国，模具制造属于专用设备制造业。
注塑模具设计与制造外文文献翻译
2 Injection molding machineFrom Plastics Wiki, free encyclopediaInjection molding machines consist of two basic parts, an injection unit and a clamping unit. Injection molding machines differ in both injection unit and clamping unit. The name of the injection molding machine is generally based on the type of injection unit used.2.1Types of injection molding machinesMachines are classified primarily by the type of driving systems they use: hydraulic, electric, or hybrid.2.1.1HydraulicHydraulic presses have historically been the only option available to molders until Nissei Plastic Industrial Co., LTD introduced the first all-electric injection molding machine in 1983. The electric press, also known as Electric Machine Technology (EMT), reduces operation costs by cutting energy consumption and also addresses some of the environmental concerns surrounding the hydraulic press.2.1.2ElectricElectric presses have been shown to be quieter, faster, and have a higher accuracy, however the machines are more expensive.2.1.3HybridHybrid injection molding machines take advantage of the best features of both hydraulic and electric systems. Hydraulic machines are the predominant type in most of the world, with the exception of Japan.2.2Injection unitThe injection unit melts the polymer resin and injects the polymer melt into the mold. The unit may be: ram fed or screw fed.The ram fed injection molding machine uses a hydraulically operated plunger to push the plastic through a heated region. The high viscosity melt is then spread into a thin layer by a "torpedo" to allow for better contact with the heated surfaces. The melt converges at a nozzle and is injected into the mold.Reciprocating screw A combination melting, softening, and injection unit in an injection molding machine. Another term for the injection screw. Reciprocating screws are capable of turning as they move back and forth.The reciprocating screw is used to compress, melt, and convey the material. The reciprocating screw consists of three zones (illustrated below):•feeding zone•compressing zone•metering zoneWhile the outside diameter of the screw remains constant, the depth of the flights on the reciprocating screw decreases from the feed zone to the beginning of the metering zone. These flights compress the material against the inside diameter of the barrel, which creates viscous (shear) heat. This shear heat is mainly responsible for melting the material. The heater bands outside the barrel help maintain the material in the molten state. Typically, a molding machine can have three or more heater bands or zones with different temperature settings.Injection molding reciprocating screw An extruder-type screw rotates within a cylinder, which is typically driven by a hydraulic drive mechanism. Plastic material is moved through the heated cylinder via the screw flights and the material becomes fluid. The injection nozzle is blocked by the previous shot, and this action causes the screw to pump itself backward through the cylinder. (During this step, material is plasticated and accumulated for the next shot.) When the mold clamp has locked, the injection phase takes place. At this time, the screw advances, acting as a ram. Simultaneously, the non-return valve closes off the escape passages in the screw and the screw serves as a solid plunger, moving the plastic ahead into the mold. When the injection stroke and holding cycle is completed, the screw is energized to return and the non-return valve opens, allowing plastic to flow forward from the cylinder again, thus repeating the cycle.2.2.1Feed hopperThe container holding a supply molding material to be fed to the screw. The hopper located over the barrel and the feed throat connects them.2.2.2Injection ramThe ram or screw that applies pressure on the molten plastic material to force it into the mold cavities.2.2.3Injection screwThe reciprocating-screw machine is the most common. This design uses the same barrel for melting and injection of plastic.The alternative unit involves the use of separate barrels for plasticizing and injecting the polymer. This type is called a screw-preplasticizer machine or two-stage machine. Plastic pellets are fed from a hopper into the first stage, which uses a screw to drive the polymer forward and melt it. This barrel feeds a second barrel, which uses a plunger to inject the melt into the mold. Older machines used one plunger-driven barrel to melt and inject the plastic. These machines are referred to as plunger-type injection molding machines.2.2.4BarrelBarrel is a major part that melts resins transmitted from hopper through screws and structured in a way that can heat up resins to the proper temperature. A band heater, which can control temper atures in five sections, is attached outside the barrel. Melted resins are supplied to the mold passing through barrel head, shot-off nozzle, and one-touch nozzle.2.2.5Injection cylinderHydraulic motor located inside bearing box, which is connected to injection cylinder load, rotates screw, and the melted resins are measures at the nose of screw. There are many types of injection cylinders that supply necessary power to inject resins according to the characteristics of resins and product types at appropriate speed and pressure. This model employs the double cylinder type. Injection cylinder is composed of cylinder body, piston, and piston load.2.3Clamping unitThe clamping unit holds the mold together, opens and closes it automatically, and ejects the finished part. The mechanism may be of several designs, either mechanical, hydraulic or hydromechanical.Toggle clamps - a type clamping unit include various designs. An actuator moves the crosshead forward, extending the toggle links to push the moving platen toward a closed position. At the beginning of the movement, mechanical advantage is low and speed is high; but near the end of the stroke, the reverse is true. Thus, toggle clamps provide both high speed and high force at different points in the cycle when they are desirable. They are actuated either by hydraulic cylinders or ball screws driven by electric motors. Toggle-clamp units seem most suited to relatively low-tonnage machines.Two clamping designs: (a) one possible toggle clamp design (1) open and (2) closed; and (b) hydraulic clamping (1) open and (2) closed. Tie rods used to guide movuing platens not shown.Hydraulic clamps are used on higher-tonnage injection molding machines, typically in the range 1300 to 8900 kN (150 to 1000 tons). These units are also more flexible than toggle clamps in terms of setting the tonnage at given positions during the stroke.Hydraulic Clamping System is using the direct hydraulic clamp of which the tolerance is still and below 1 %, of course, better than the toggle system. In addition, the Low Pressure Protection Device is higher than the toggle system for 10 times so that the protection for the precision and expensive mold is very good. The clamping force is focus on the central for evenly distribution that can make the adjustment of the mold flatness in automatically. Hydromechanical clamps -clamping units are designed for large tonnages, usually above 8900 kN (1000 tons); they operate by (1) using hydraulic cylinders to rapidly move the mold toward closing position, (2) locking the position by mechanical means, and (3) using high pressure hydraulic cylinders to finally close the mold and build tonnage.2.3.1Injection moldThere are two main types of injection molds: cold runner (two plate and three plate designs) and hot runner– the more common of the runnerless molds.2.3.2Injection platensSteel plates on a molding machine to which the mold is attached. Generally, two platens are used; one being stationary and the other moveable, actuated hydraulically to open and close the mold. It actually provide place to mount the mould. It contains threaded holes on which mould can be mounted using clamps.2.3.3Clamping cylinderA device that actuates the chuck through the aid of pneumatic or hydraulic energy.2.3.4Tie BarTie bars support clamping power, and 4 tie bars are located between the fixing platen and the support platen.3 Injection mouldFrom Wikipedia, the free encyclopediaMold A hollow form or cavity into which molten plastic is forced to give the shape of the required component. The term generally refers to the whole assembly of parts that make up the section of the molding equipment in which the parts are formed. Also called a tool or die. Moulds separate into at least two halves (called the core and the cavity) to permit the part to be extracted; in general the shape of a part must be such that it will not be locked into the mould. For example, sides of objects typically cannot be parallel with the direction of draw (the direction in which the core and cavity separate from each other). They are angled slightly; examination of most household objects made from plastic will show this aspect of design, known as draft. Parts that are "bucket-like" tend to shrink onto the core while cooling and, after the cavity is pulled away, are typically ejected using pins. Parts can be easily welded together after moulding to allow for a hollow part (like a water jug or doll's head) that couldn't physically be designed as one mould.More complex parts are formed using more complex moulds, which may require moveable sections, called slides, which are inserted into the mould to form particular features that cannot be formed using only a core and a cavity, but are then withdrawn to allow the part to be released. Some moulds even allow previously moulded parts to be re-inserted to allow a new plastic layer to form around the first part. This system can allow for production of fully tyred wheels.Traditionally, moulds have been very expensive to manufacture; therefore, they were usually only used in mass production where thousands of parts are being produced.Molds require: Engineering and design, special materials, machinery and highly skilled personnel to manufacture, assemble and test them.Cold-runner moldCold-runner mold Developed to provide for injection of thermoset material either directly into the cavity or through a small sub-runner and gate into the cavity. It may be compared to the hot-runner molds with the exception that the manifold section is cooled rather than heated to maintain softened but uncured material. The cavity and core plates are electrically heated to normal molding temperature and insulated from the cooler manifold section.3.1.1Types of Cold Runner MoldsThere are two major types of cold runner molds: two plate and three plate.3.1.2Two plate moldA two plate cold runner mold is the simplest type of mold. It is called a two plate mold because there is one parting plane, and the mold splits into two halves. The runner system must be located on this parting plane; thus the part can only be gated on its perimeter.3.1.3Three plate moldA three plate mold differs from a two plate in that it has two parting planes, and the mold splits into three sections every time the part is ejected. Since the mold has two parting planes, the runner system can be located on one, and the part on the other. Three plate molds are used because of their flexibility in gating location. A part can be gated virtually anywhere along its surface.3.1.4AdvantagesThe mold design is very simple, and much cheaper than a hot runner system. The mold requires less maintenance and less skill to set up and operate. Color changes are also very easy, since all of the plastic in the mold is ejected with each cycle.3.1.5DisadvantagesThe obvious disadvantage of this system is the waste plastic generated. The runners are either disposed of, or reground and reprocessed with the original material. This adds a step in the manufacturing process. Also, regrind will increase variation in the injection molding process, and could decrease the plastic's mechanical properties.3.1.6Hot runner moldHot-runner mold -injection mold in which the runners are kept hot and insulated from the chilled cavities. Plastic freezeoff occurs at gate of cavity; runners are in a separate plate so they are not, as is the case usually, ejected with the piece.Hot runner molds are two plate molds with a heated runner system inside one half of the mold.A hot runner system is divided into two parts: the manifold and the drops. The manifold has channels that convey the plastic on a single plane, parallel to the parting line, to a point abovethe cavity. The drops, situated perpendicular to the manifold, convey the plastic from the manifold to the part.3.1.7Types of Hot Runner MoldsThere are many variations of hot runner systems. Generally, hot runner systems are designated by how the plastic is heated. There are internally and externally heated drops and manifolds.3.1.8Externally heated hot runnersExternally heated hot runner channels have the lowest pressure drop of any runner system (because there is no heater obstructing flow and all the plastic is molten), and they are better for color changes none of the plastic in the runner system freezes. There are no places for material to hang up and degrade, so externally heated systems are good for thermally sensitive materials.3.1.9Internally heated hot runnersInternally heated runner systems require higher molding pressures, and color changes are very difficult. There are many places for material to hang up and degrade, so thermally sensitive materials should not be used. Internally heated drops offer better gate tip control. Internally heated systems also better separate runner heat from the mold because an insulating frozen layer is formed against the steel wall on the inside of the flow channels.3.1.10 insulated hot runnersA special type of hot runner system is an insulated runner. An insulated runner is not heated; the runner channels are extremely thick and stay molten during constant cycling. This system is very inexpensive, and offers the flexible gating advantages of other hot runners and the elimination of gates without the added cost of the manifold and drops of a heated hot runner system. Color changes are very easy. Unfortunately, these runner systems offer no control, and only commodity plastics like PP and PE can be used. If the mold stops cycling for some reason, the runner system will freeze and the mold has to be split to remove it. Insulated runners are usually used to make low tolerance parts like cups and frisbees.3.1.11 DisadvantagesHot-runner mold is much more expensive than a cold runner, it requires costly maintenance, and requires more skill to operate. Color changes with hot runner molds can be difficult, since it is virtually impossible to remove all of the plastic from an internal runner system.3.1.12 AdvantagesThey can completely eliminate runner scrap, so there are no runners to sort from the parts, and no runners to throw away or regrind and remix into the original material. Hot runners are popular in high production parts, especially with a lot of cavities.Advantages Hot Runner System Over a Cold Runner System include:•no runners to disconnect from the molded parts•no runners to remove or regrind, thus no need for process/ robotics to remove them•having no runners reduces the possibility of contamination•lower injection pressures•lower clamping pressure•consistent heat at processing temperature within the cavity•cooling time is actually shorter (as there is no need for thicker, longer-cycle runners)•shot size is reduced by runner weight•cleaner molding process (no regrinding necessary)•nozzle freeze and sprue sticking issues eliminated中文翻译注塑模具设计与制造2 注射机选自《维基百科》注射机由两个基本部分组成，注射装置和夹紧装置。
外文翻译-模具类注塑机模具设计
外文翻译-模具类注塑机模具设计外文翻译毕业设计题目:操纵机构及其面板凸轮机构模具设计原文1:Plastic Material Molding译文1:塑料成型原文2:The Injection-molding Maching 译文2:注塑机Plastic Material MoldingPlastic objects are formed by comperssion,transfer,and injection molding.Other processes arecasting, extrusion and laminating, filament winding, sheet forming, jointing, foaming, andmaching. Some of these and still otherrs are used for rubber. A reason for a variety of processes isthat different materials must be worked in differentways. Also, each methods is advantageous for certain kind of product(Table 1)Table 1 Characteristics of Forming and Shaping Processesfor Plastics and Composite Materialsprocess CharacteristicsExtrusion Long, uniform, solid or hollow complex cross-sections;high production rates; low tooling costs; widetolerrances.Injection molding Complex shapes of various sizes, eliminating assembly;high production rates; costly tooling; good dimensionalaccurancy.Structural foam molding Large parts with high stiffness-to-weight ratio; lessexpensive tooling than in injection molding; lowproduction rates.Blow molding Hollow thin-walled parts of various sizes; highproduction rates and low cost for making containers.Rotational molding Large hollow shapes of relatively simple shape;lowtooling cost; low production rates.Thermoforming Shallow or relatively deep cavities; low tooling costs;medium production rates.Compression molding Parts similar to impression-die forging;relativelyinpensive tooling; medium production rates.Transfer molding More complex parts than compression molding andhigher production rates; some scrap loss; mediumtooling cost.1Casting Simple or intricate shapes made with flexible molds;low production rates.Processing of composite materials Long cycle time; tolerances and tooling cost depend onprocess.There are two main steps in the manufacture of plastic products. The first is a chemical process to create the resin. The second is to mixand shape all the material into the finished article or product.1.1 Compression MoldingIn compression molding, a preshaped charge of material, a premeasured volume of powder, or a viscous mixture of liquid redin and filler material is placed directly into a heated mold cavity. Forming is done under pressure from a plug or from the upper half of the die (Figer 1). Compression molding results in the formation of flash (if additional plastic is forced between the mold halves, because of a poor mold fit or wear, it is called flash.), which is subsequently removed by trimming or other means.Typical parts made are dishes, handles, container caps, fittings, electrical and electronic components, washing-machine agitators, and housings. Fiber-reinforced parts with long chopped fibers are formed by this process exclusively.Compression molding is used mainly with thermosetting plastics, with the original material being in a partially ploymerized state. Cross-linking (in these ploymers, additional element link one chain to another. The best example is the use of sulfur to cross-link elastomers to create automobile tires) is completed in the heated die; curing times rang from0.5 to 5 minutes, depending on the material and on part thickness and geometry. The thicker the material is, the longer it will take to cure. Elastomers are also shaped by compression molding.Three types of compression molds are available as follows:2Figuer 1 Typres of compression moldinga. flash-type, for shallow or flat parts,b. positive, for high density parts,c. semipositive, for quality production.1.2 Transfer MoldingTransfer molding represents a further development of compression molding. The uncured thermosetting material is placed in a heatedtransfer pot or chamber (Figer 2). After the materialis heated, it is injected into heated closed molds. A ram, a plunger, or a rotating-screw feeder (depending on the type of machine used)forces the material to flow through the narrow channels into the mold cavity.Typical parts made by transfer molding are electrical and electronic components and rubber and silicone parts. This process is particularly suitable for intricate parts with varying wall thickness.1.3 Injection MoldingInjection molding (injection of plastic into a catity of desired shape. The plastic is then cooled and ejected in its final form. Most consumer productions such as telephones, computer casings, and CD players are injection molded. ) is principally used for the production of thermoplastic parts, although some process has been made in developing a method for injection molding some3thermosetting materials.Figure 2 Sequence of operations in transfer molding forthermosetting plastics The problem of injection a melted plastic into a mold cavity from a reservoir melted material has been extremelydifficult to solve for thermosetting plastics which cure and harden such conditions within a few minutes. The principle of injection molding is quite similar to that of die-casting. Plastic powder is loaded into thefeed hopper and a certain amount feeds into the heating chamber when the plunger draws back. The plastic powder under heat and pressures in the heating chamber becomes a fluid. After the mold is closed, the plunger moves forward, forcing some of the fluid plastic into the mold cavity under pressures. Since the mold in cooled by circulating cold water, the plastic hardens and the part may be ejected when the plunger draws back and the mold opens. Injection-molding machines can be arranged for manual operation, automatic single-cycle operation, and ful automatic operation. Typical machines produce molded parts weighing up to 22 ounces at the rate of four shots per minute, and it is possible on molded parts machines to obtain a rate of six shots per minute. The molds used are similar to the dies of a die-casting machine. The advantages of injection molding are as follows:1. A high molding speed adapted for mass production is possible,2. There is a wide choice of thermoplastic materials providing a variety of usefulproperties,3. It is possible to mold threads,(“sideways” racesses or projections of the molded part thatprevent its removal from the mold along the parting direction. They can accommodated4by specialized mold design such as sliders.), side holes, and large thin sections. 1.4 Thermoplastic Mold DesignBasically, there are two types of transfer mold: the conventional sprue type and the positive plunger type. In the sprue type the plastic performs are placed in a separate loading chamber above the mold cavity. One or more sprues (the runway between the injection machine's nozzle and the runners or the gate) lead down to the parting surface of the mold where they connect with gates to the mold cavity or cavities (Figer 3). Special press with a floating intermediate platen are especially useful for accommodating the two parting surface molds. The plunger acts directly on the plastic material, forcing it through the sprues and gates into the mold cavities. Heat and pressure must be maintained for a definite time for curing. When the part is cured the press is opened, breaking the sprues from the gates. The cull and sprues and raised upward, being held by a tapered, dovetailed projection machine on the end ofFigure 3 Schematic illustration of transfer moldingthe plunger. They can easily be removed from the dovetail by pushing horizontally. In a positive plunger-type transfer mold the sprue is eliminated so that the loading chamber extends through to the mold parting surface and connects directly with the gates (the entrance to the mold cavity). The positive plunger type is preferred, because themold is less complicated, and less material is wasted. Parts made by transfer molding have greater strength, more uniform densities, closer dimensional tolerances, and the parting plane (the separation plane of the two mold halves) requires less cleaning as compression molding.The following figure shows a typical two-plate mold and indicates the structure of mold and the arrangement of all parts in mold (Figure4).5Figure 4 The typical structure of two-plate mold作者:Yijun Huang国籍:china出处:Qinghua university press6塑料成型塑料制品一般是由压缩，传递和注塑成型等方法形成的。
注塑模具设计注射模具毕业课程设计外文文献翻译
The Injection MoldingThe Introduction of MoldsThe mold is at the core of a plastic manufacturing process because its cavity gives a part its shape. This makes the mold at least as critical-and many cases more so-for the quality of the end product as, for example, the plasticiting unit or other components of the processing equipment.Mold MaterialDepending on the processing parameters for the various processing methods as well as the length of the production run, the number of finished products to be produced, molds for plastics processing must satisfy a great variety of requirements. It is therefore not surprising that molds can be made from a very broad spectrum of materials, including-from a technical standpoint-such exotic materials as paper matched and plaster. However, because most processes require high pressures, often combined with high temperatures, metals still represent by far the most important material group, with steel being the predominant metal. It is interesting in this regard that, in many cases, the selection of the mold material is not only a question of material properties and an optimum price-to-performance ratio but also that the methods used to produce the mold, and thus the entire design, can be influenced.A typical example can be seen in the choice between cast metal molds, with their very different cooling systems, compared to machined molds. In addition, the production technique can also have an effect; for instance, it is often reported that, for the sake of simplicity, a prototype mold is frequently machined from solid stock with the aid of the latest technology such as computer-aided (CAD) and computer-integrated manufacturing (CIM S). In contrast to the previously used methods based on the use of patterns, the use of CAD and CAM often represents the more economical solution today, not only because this production capability is available pin-house but also because with any other technique an order would have to be placed with an outside supplier.Overall, although high-grade materials are often used, as a rule standard materials are used in mold making. New, state-of-the art (high-performance) materials, such as ceramics, for instance, are almost completely absent. This may be related to the fact that their desirable characteristics, such as constant properties up to very high temperatures, are not required on molds, whereas their negative characteristics, e. g. low tensile strength and poor thermal conductivity, have a clearly related to ceramics, such as sintered material, is found in mild making only to a limited degree. This refers less to the modern materials and components produced by powder metallurgy, and possibly by hot isocratic pressing, than to sintered metals in the sense of porous, air-permeable materials.Removal of air from the cavity of a mold is necessary with many different processing methods, and it has been proposed many times that this can be accomplished using porous metallic materials. The advantages over specially fabricated venting devices, particularly in areas where melt flow fronts meet, I, e, at weld lines, are as obvious as the potential problem areas: on one hand, preventing the texture of such surfaces from becoming visible on the finished product, and on the other hand, preventing the microspores from quickly becoming clogged with residues (broken off flash, deposits from the molding material, so-called plate out, etc.). It is also interesting in this case that completely new possibilities with regard to mold design and processing technique result from the use of such materials.A. Design rulesThere are many rules for designing molds. These rules and standard practices are based on logic, past experience, convenience, and economy. For designing, mold making, and molding, it is usually of advantage to follow the rules. But occasionally, it may work out better if a rule is ignored and an alternative way is selected. In this text, the most common rules are noted, but the designer will learn only from experience which way to go. The designer must ever be open to new ideas and methods, to new molding and mold materials that may affect these rules.B. The basic mold1. Mold cavity spaceThe mold cavity space is a shape inside the mold, “excavated” in such a manner that when the molding material is forced into this space it will take on the shape of the cavity space and, therefore, the desired product. The principle of a mold is almost as old as human civilization. Molds have metals into sand forms. Such molds, which are still used today in foundries, can be used only once because the mold is destroyed to release the product after it has solidified. Today, we are looking for permanent molds that can be used over and over. Now molds are made from strong, durable materials, such as steel, or from softer aluminum or metal alloys and even from certain plastics where a long mold life is not required because the planned production is small. In injection molding the plastic is injected into the cavity space with high pressure, so the mold must be strong enough to resist the injection pressure without deforming.2. Number of cavitiesMany molds, particularly molds for larger products, are built for only cavity space, but many molds, especially large production molds, are built with 2 or more cavities. The reason for this is purely economical. It takes only little more time to inject several cavities than to inject one. For example, a 4-cavity mold requires only one-fourth of the machine time of asingle-cavity mold. Conversely, the production increases in proportion to the number of cavities. A mold with more cavities is more expensive to build than a single-cavity mold, but not necessarily 4 times as much as a single-cavity mold. But it may also require a larger machine with larger platen area and more clamping capacity, and because it will use 4 times the amount of plastic, it may need a large injection unit, so the machine hour cost will be higher than for a machine large enough for the smaller mold.3. Cavity shape and shrinkageThe shape of the cavity is essenti ally the “negative” of the shape of the desired product, with dimensional allowance added to allow for shrinking of the plastic. The shape of the cavity is usually created with chip-removing machine tools, or with electric discharge machining, with chemical etching, or by any new method that may be available to remove metal or build it up, such as galvanic processes. It may also be created by casting certain metals in plaster molds created from models of the product to be made, or by casting some suitable hard plastics. The cavity shape can be either cut directly into the mold plates or formed by putting inserts into the plates.C. Cavity and coreBy convention, the hollow portion of the cavity space is called the cavity. The matching, often raised portion of the cavity space is called the core. Most plastic products are cup-shaped. This does not mean that they look like a cup, but they do have an inside and an outside. The outside of the product is formed by the cavity, the inside by the core. The alternative to the cup shape is the flat shape. In this case, there is no specific convex portion, and sometimes, the core looks like a mirror image of the cavity. Typical examples for this are plastic knives, game chips, or round disks such as records. While these items are simple in appearance, they often present serious molding problems for ejection of the product. The reason for this is that all injection molding machines provide an ejection mechanism on the moving platen and the products tend to shrink onto and cling to the core, from where they are then ejected. Most injection molding machines do not provide ejection mechanisms on the injection side.Polymer ProcessingPolymer processing, in its most general context, involves the transformation of a solid (sometimes liquid) polymeric resin, which is in a random form (e.g., powder, pellets, beads), to a solid plastics product of specified shape, dimensions, and properties. This is achieved by means of a transformation process: extrusion, molding, calendaring, coating, thermoforming, etc. The process, in order to achieve the above objective, usually involves the following operations: solid transport, compression, heating, melting, mixing, shaping, cooling,solidification, and finishing. Obviously, these operations do not necessarily occur in sequence, and many of them take place simultaneously.Shaping is required in order to impart to the material the desired geometry and dimensions. It involves combinations of viscoelastic deformations and heat transfer, which are generally associated with solidification of the product from the melt.Shaping includes: two-dimensional operations, e.g. die forming, calendaring and coating; three-dimensional molding and forming operations. Two-dimensional processes are either of the continuous, steady state type (e.g. film and sheet extrusion, wire coating, paper and sheet coating, calendaring, fiber spinning, pipe and profile extrusion, etc.) or intermittent as in the case of extrusions associated with intermittent extrusion blow molding. Generally, molding operations are intermittent, and, thus, they tend to involve unsteady state conditions. Thermoforming, vacuum forming, and similar processes may be considered as secondary shaping operations, since they usually involve the reshaping of an already shaped form. In some cases, like blow molding, the process involves primary shaping (pair-son formation) and secondary shaping (pair son inflation).Shaping operations involve simultaneous or staggered fluid flow and heat transfer. In two-dimensional processes, solidification usually follows the shaping process, whereas solidification and shaping tend to take place simultaneously inside the mold in three dimensional processes. Flow regimes, depending on the nature of the material, the equipment, and the processing conditions, usually involve combinations of shear, extensional, and squeezing flows in conjunction with enclosed (contained) or free surface flows.The thermo-mechanical history experienced by the polymer during flow and solidification results in the development of microstructure (morphology, crystallinity, and orientation distributions) in the manufactured article. The ultimate properties of the article are closely related to the microstructure. Therefore, the control of the process and product quality must be based on an understanding of the interactions between resin properties, equipment design, operating conditions, thermo-mechanical history, microstructure, and ultimate product properties. Mathematical modeling and computer simulation have been employed to obtain an understanding of these interactions. Such an approach has gained more importance in view of the expanding utilization of computer design/computer assisted manufacturing/computer aided engineering (CAD/CAM/CAE) systems in conjunction with plastics processing.It will emphasize recent developments relating to the analysis and simulation of some important commercial process, with due consideration to elucidation of both thermo-mechanical history and microstructure development.As mentioned above, shaping operations involve combinations of fluid flow and heattransfer, with phase change, of a visco-elastic polymer melt. Both steady and unsteady state processes are encountered. A scientific analysis of operations of this type requires solving the relevant equations of continuity, motion, and energy (I. e. conservation equations).Injection MoldingMany different processes are used to transform plastic granules, powders, and liquids into final product. The plastic material is in moldable form, and is adaptable to various forming methods. In most cases thermoplastic materials are suitable for certain processes while thermosetting materials require other methods of forming. This is recognized by the fact that thermoplastics are usually heated to a soft state and then reshaped before cooling. Theromosets, on the other hand have not yet been polymerized before processing, and the chemical reaction takes place during the process, usually through heat, a catalyst, or pressure. It is important to remember this concept while studying the plastics manufacturing processes and the polymers used.Injection molding is by far the most widely used process of forming thermoplastic materials. It is also one of the oldest. Currently injection molding accounts for 30% of all plastics resin consumption. Since raw material can be converted by a single procedure, injection molding is suitable for mass production of plastics articles and automated one-step production of complex geometries. In most cases, finishing is not necessary. Typical products include toys, automotive parts, household articles, and consumer electronics goods,Since injection molding has a number of interdependent variables, it is a process of considerable complexity. The success of the injection molding operation is dependent not only in the proper setup of the machine variables, but also on eliminating shot-to-shot variations that are caused by the machine hydraulics, barrel temperature variations, and changes in material viscosity. Increasing shot-to-shot repeatability of machine variables helps produce parts with tighter tolerance, lowers the level of rejects, and increases product quality ( i.e., appearance and serviceability).The principal objective of any molding operation is the manufacture of products: to a specific quality level, in the shortest time, and using a repeatable and fully automatic cycle. Molders strive to reduce or eliminate rejected parts, or parts with a high added value such as appliance cases, the payoff of reduced rejects is high.A typical injection molding cycle or sequence consists of five phases:1 Injection or mold filling2 Packing or compression3 Holding4 Cooling5 Part ejectionInjection Molding OverviewProcessInjection molding is a cyclic process of forming plastic into a desired shape by forcingthe material under pressure into a cavity. The shaping is achieved by cooling (thermoplastics) or by a chemical reaction (thermosets). It is one of the most commonand versatile operations for mass production of complex plastics parts with excellent dimensional tolerance. It requires minimal or no finishing or assembly operations. In addition to thermoplastics and thermosets, the process is being extended to suchmaterials as fibers, ceramics, and powdered metals, with polymers as binders.ApplicationsApproximately 32 percent by weight of all plastics processed go through injection molding machines. Historically, the major milestones of injection molding include the invention of the reciprocating screw machine and various new alternative processes, and the application of computersimulation to the design and manufacture of plastics parts.Development of the injection molding machineSince its introduction in the early 1870s, the injection molding machine has undergone significantmodifications and improvements. In particular, the invention of the reciprocating screw machine hasrevolutionized the versatility and productivity of the thermoplastic injection molding process.Benefits of the reciprocating screwApart from obvious improvements in machine control and machine functions, the major development for the injection molding machine is the change from a plunger mechanism to a reciprocating screw. Although the plunger-type machine is inherently simple, its popularity waslimited due to the slow heating rate through pure conduction only. The reciprocating screw canplasticize the material more quickly and uniformly with its rotating motion, as shown in Figure 1. Inaddition, it is able to inject the molten polymer in a forward direction, as a plunger.Development of the injection molding processThe injection molding process was first used only with thermoplastic polymers. Advances in theunderstanding of materials, improvements in molding equipment, and the needs of specific industrysegments have expanded the use of the process to areas beyond its original scope. Alternative injection molding processesDuring the past two decades, numerous attempts have been made to develop injection moldingprocesses to produce parts with special design features and properties. Alternative processes derivedfrom conventional injection molding have created a new era for additional applications, more designfreedom, and special structural features. These efforts have resulted in a number of processes,including:Co-injection (sandwich) moldingFusible core injection molding)Gas-assisted injection moldingInjection-compression moldingLamellar (microlayer) injection moldinLive-feed injection moldingLow-pressure injection moldingPush-pull injection moldingReactive moldingStructural foam injection moldingThin-wall moldingComputer simulation of injection molding processesBecause of these extensions and their promising future, computer simulation of the process has alsoexpanded beyond the early "lay-flat," empirical cavity-filling estimates. Now, complex programs simulate post-filling behavior, reaction kinetics, and the use of two materials with different properties, or two distinct phases, during the process.The Simulation section provides information on using C-MOLD products.Among the Design topicsare several examples that illustrate how you can use CAE tools to improve your part and molddesign and optimize processing conditions.Co-injection (sandwich) moldingOverviewCo-injection molding involves sequential or concurrent injection of two different but compatible polymer melts into a cavity. The materials laminate and solidify. This process produces parts that have a laminated structure, with the core material embedded betweenthe layers of the skin material. This innovative process offers the inherent flexibility ofusing the optimal properties of each material or modifying the properties of the molded part.FIGURE 1. Four stages of co-injection molding. (a) Short shot of skin polymer melt (shown in dark green)is injected into the mold. (b) Injection of core polymer melt until cavity is nearly filled, as shown in (c). (d)Skin polymer is injected again, to purge the core polymer away from the sprue.Fusible core injection moldingOverviewThe fusible (lost, soluble) core injection molding process illustrated below producessingle-piece, hollow parts with complex internal geometry. This process molds a coreinside the plastic part. After the molding, the core will be physically melted or chemically dissolved, leaving its outer geometry as the internal shape of the plastic part.FIGURE 1. Fusible (lost, soluble) core injection moldingGas-assisted injection moldingGas-assisted processThe gas-assisted injection molding process begins with a partial or full injection ofpolymer melt into the mold cavity. Compressed gas is then injected into the core of the polymer melt to help fill and pack the mold. This process is illustrated below.FIGURE 1. Gas-assisted injection molding: (a) the electrical system, (b) the hydraulic system, (c) the control panel, and (d) the gas cylinder.Injection-compression moldingOverviewThe injection-compression molding process is an extension of conventional injection molding. After a pre-set amount of polymer melt is fed into an open cavity, it is compressed, as shown below. The compression can also take place when the polymer isto be injected. The primary advantage of this process is the ability to produce dimensionally stable, relatively stress-free parts, at a low clamp tonnage (typically 20 to 50 percent lower).Lamellar (microlayer) injection moldingOverviewThis process uses a feedblock and layer multipliers to combine melt streams from dual injection cylinders. It produces parts from multiple resins in distinct microlayers, as shown in Figure 1 below. Combining different resins in a layered structure enhances a number of properties, such as the gas barrier property, dimensional stability, heat resistance, and optical clarity.Live-feed injection moldingOverviewThe live-feed injection molding process applies oscillating pressure at multiple polymer entrances to cause the melt to oscillate, as shown in the illustration below. The action of the pistons keeps the material in the gates molten while different layers of molecular or fiber orientation are being built up in the mold due to solidification. This process provides a means of making simple or complex parts that are free from voids, cracks, sink marks, and weld-line defects.Low-pressure injection moldingOverviewLow-pressure injection molding is essentially an optimized extension of conventional injection molding (see Figure 1). Low pressure can be achieved by properly programming the screw revolutions per minute, hydraulic back pressure, and screw speed to controlthe melt temperature and the injection speed. It also makes use of a generous gate size ora n reduce umber of valve gates that open and close sequentially to reduce the flow length. Thepacking stage is eliminated with a generally slow and controlled injection speed. The benefits of low-pressure injection molding include a reduction of the clamp force tonnage requirement, less costly molds and presses, and lower stress in the molded parts.Push-pull injection moldingOverviewThe push-pull injection molding process uses a conventional twin-component injection system and a two-gate mold to force material to flow back and forth between a master injection unit and a secondary injection unit, as shown below. This process eliminatesweld lines, voids, and cracks, and controls the fiber orientation.Reactive moldingProcessingMajor reactive molding processes include reactive injection molding (RIM), and composites processing, such as resin transfer molding (RTM) and structural reactive injection molding (SRIM).The typically low viscosity of the reactive materials permits large and complex parts to be moldedwith relatively lower pressure and clamp tonnage than required for thermoplastics molding. relatively For example, to make high-strength and low-volume large parts, RTM and SRIM can be used to include a preform made of long fibers. Another area that is receiving more attention than ever before is the encapsulation of microelectronic IC chips.The adaptation of injection molding to these materials includes only a small increase in temperature in the feed mechanism (barrel) to avoid pre-curing. The cavity, however, is usually hot enough to initiate chemical cross-linking. As the warm pre-polymer is forced into the cavity, heat is added from the cavity wall, from viscous (frictional) heating of the flow, and from the heat released by the reacting components. The temperature of the part often exceeds the temperature of the mold. When the reaction is sufficiently advanced for the part to be rigid (even at a high temperature) the cycle is complete and the part is ejected.Design considerationsThe mold and process design for injection molding of reactive materials is much more complexbecause of the chemical reaction that takes place during the filling and post-filling stages. For instance, slow filling often causes premature gelling and a resultant short shot, while fast fillingcould induce turbulent flow that creates internal porosity. Improper control of mold-wall temperature and/or inadequate part thickness will either give rise to moldability problems duringinjection, or cause scorching of the materials. Computer simulation is generally recognized as amore cost-effective tool than the conventional, time-consuming trial-and-error method for tool andprocess debugging.Structural foam injection moldingOverviewStructural foam molding produces parts consisting of solid external skin surfaces surrounding an inner cellular (or foam) core, as illustrated in Figure 1 below. This processis suitable for large, thick parts that are subject to bending loads in their end-use application. Structural foam parts can be produced with both low and high pressure, withnitrogen gas or chemical blowing agents.Thin-wall moldingOverviewThe term "thin-wall" is relative. Conventional plastic parts are typically 2 to 4 mm thick. Thin-wall designs are called "advanced" when thicknesses range from 1.2 to 2 mm, and "leading-edge" when the dimension is below 1.2 mm. Another definition of thin-wall molding is based on the flow-length-to-wall-thickness ratios. Typical ratios for thesethin-wall applications range from 100:1 to 150:1 or more.Typical applicationsThin-wall molding is more popular in portable communication and computing equipment, whichdemand plastic shells that are much thinner yet still provide the same mechanical strength as conventional parts.ProcessingBecause thin-wall parts freeze off quickly, they require high melt temperatures, high injectio speeds, and very high injection pressures if multiple gates or sequential valve gating are not an optimized ram-speed profile helps to reduce the pressure requirement.Due to the high velocity and shear rate in thin-wall molding, orientation occurs more readily help minimize anisotropic shrinkage in thin-wall parts, it is important to pack the part adequately while the core is still molten.Injection molding machineComponentsFor thermoplastics, the injection molding machine converts granular or pelleted rawplastic into final molded parts via a melt, inject, pack, and cool cycle. A typical injection molding machine consists of the following major components, as illustrated in Figure 1 below.Machine functionInjection molding machines can be generally classified into three categories, based on machinefunction:General-purpose machinesPrecision, tight-tolerance machinesHigh-speed, thin-wall machinesAuxiliary equipmentThe major equipment auxiliary to an injection molding machine includes resin dryers, materials-handling equipment, granulators, mold-temperature controllers and chillers, part-removal robots, and part-handling equipment.中文翻译注塑模设计模具简介模具型腔可赋予制品其形状，因此在塑料加工过程中模具处于非常重要的地位，这使得模具对于产品最终质量的影响与塑化机构和其他成型设备的部件一样关键，有时甚至更重要。
塑料模具毕业外文文献翻译、塑料制品的CADCAE集成的注塑模具设计系统外文翻译、中英文翻译
A CAD/CAE-integrated injection mold design system for plastic productsAbstract Mold design is a knowledge-intensive process. This paper describes a knowledge-based oriented, parametric, modular and feature-based integrated computer-aided design/computer-aided engineering (CAD/CAE) system for mold design. Development of CAx systems for numerical simulation of plastic injection molding and mold design has opened new possibilities of product analysis during the mold design. The proposed system integrates Pro/ENGINEER system with the specially developed module for the calculation of injection molding parameters, mold design, and selection of mold elements. The system interface uses parametric and CAD/CAE feature-based database to streamline the process of design, editing, and reviewing. Also presented are general structure and part of output results from the proposed CAD/ CAE-integrated injection mold design system.Keywords Mold design . Numerical simulation . CAD . CAE1 IntroductionInjection molding process is the most common molding process for making plastic parts. Generally, plastic injection molding design includes plastic product design, mold design, and injection molding process design, all of which contribute to the quality of the molded product as well as production efficiency [1]. This is process involving many design parameters that need to be considered in a concurrent manner. Mold design for plastic injection molding aided by computers has been focused by a number of authors worldwide for a long period. Various authors have developed program systems which help engineers to design part, mold, and selection parameters of injection molding. During the last decade, many authors have developed computer-aided design/computer-aided engineering (CAD/CAE) mold design systems for plastic injection molding. Jong et al. [2] developed a collaborative integrated design system for concurrent mold design within the CAD mold base on the web, using Pro/E. Low et al. [3] developed an application for standardization of initial design of plastic injection molds. The system enables choice and management of mold base of standard mold plates, but does not provide mold and injection molding calculations. The authors proposed a methodology of standardizing the cavity layout design system for plastic injection mold such that only standard cavity layouts are used. When standard layouts are used, their layout configurations can be easilystored in a database. Lin at al. [4, 5] describe a structural design system for 3D drawing mold based on functional features using a minimum set of initial information. In addition, it is also applicable to assign the functional features flexibly before accomplishing the design of a solid model for the main parts of a drawing mold. This design system includes modules for selection and calculation of mold components. It uses Pro/E modules Pro/Program and Pro/Toolkit, and consists of modules for mold selection, modification and design. Deng et al. [6, 7] analyzed development of the CAD/CAE integration. The authors also analyzed systems and problems of integration between CAD and CAE systems for numerical simulation of injection molding and mold design. Authors propose a feature ontology consisting of a number of CAD/CAE features. This feature represents not only the geometric information of plastic part, but also the design intent is oriented towards analysis. Part features contain the overall product information of a plastic part, wall features, development features (such as chamfer, ribs, boss, hole, etc.), treatment features which contain analysis-related design information and sub wall developed features. Wall and development features are so called “component features〞. God ec et al. [8, 9] developed a CAE system for mold design and injection molding parameters calculations. The system is based on morphology matrix and decision diagrams. The system is used for thermal, rheological and mechanical calculation, and material base management,Fig. 1 General structure of integrated injection mold design system for plastic productsbut no integration with commercial CAx software is provided. Huang et al. [10] developed a mold-base design system for injection molding. The database they used was parametric and feature-based oriented. The system used Pro/E for modeling database components. Kong et al. [11]developed a parametric 3D plastic injection mold design system integrated with solid works. Other knowledge-based systems, such as IMOLD, ESMOLD, IKMOULD, and IKBMOULD, have been developed for injection mold design. IMOLD divides mold design into four major steps; parting surface design, impression design, runner system design, and mold-base design. The software uses a knowledge-based CAD system to provide an interactive environment, assist designers in the rapid completion of mold design, and promote the standardization of the mold design process. IKB-MOULD application consists of databases and knowledge bases for mold manufacturing. Lou et al. [12] developed an integrated knowledge-based system for mold base design. The system has module for impression calculation, dimension calculation, calculation of the number of mold plates and selection of injection machine. The system uses Pro/ Mold Base library. This paper describes KBS and key technologies, such as product modeling, the frame-rule method, CBS, and the neural networks. A multilayer neural network has been trained by back propagation BP. This neural network adopts length, width, height and the number of parts in the mold as input and nine parameters (length, width, and height of up and down set-in, mold bases side thickness, bottom thickness of the core, and cavity plates) as output. Mok et al. [13, 14] developed an intelligent collaborative KBS for injection molds. Mok at el. [15] has developed an effective reuse and retrieval system that can register modeled standard parts using a simple graphical user interface even though designers may not know the rules of registration for a database. The mold design system was developed using an Open API and commercial CAD/computer aided manufacturing (CAM)/CAE solution. The system was applied to standardize mold bases and mold parts in Hyundai Heavy Industry. This system adopted the method of design editing, which implements the master model using features. The developed system provides methods whereby designers can register the master model, which is defined as a function of 3D CAD, as standard parts and effectively reuse standard parts even though they do not recognize the rules of the database.Todic et al. [16] developed a software solution for automated process planning for manufacturing of plastic injection molds. This CAD/CAPP/CAM system does not provide CAE calculation of parameters of injection molding and mold design. Maican et al. [17] used CAE for mechanical, thermal, and rheological calculations. They analyzed physical, mechanical, and thermal properties of plastic materials. They defined the critical parameters of loaded part. Nardinet al. [18] tried to develop the system which would suit all the needs of the injection molding for selection of the part–mold–technology system. The simulation results consist of geometrical and manufacturing data. On the basis of the simulation results, part designers can optimize part geometry, while mold designers can optimize the running and the cooling system of the mold. The authors developed a program which helps the programmers of the injection molding machine to transfer simulation data directly to the machine. Zhou et al. [1] developed a virtual injection molding system based on numerical simulation. Ma et al. [19] developed standard component library for plastic injection mold design using an object-oriented approach. This is an objector iented, library model for defining mechanical components parametrically. They developed an object-oriented mold component library model for incorporating different geometric topologies and non-geometric information. Over the years, many researchers have attempted to automate a wholeFig. 2 Structure of module for numerical simulation of injection molding processFig. 3 Forms to define the mold geometrymold design process using various knowledge-based engineering (KBE) approaches, such as rule-based reasoning (RBR), and case base (CBR) and parametric design template (PDT). Chan at al. [20] developed a 3D CAD knowledge-based assisted injection mold design system (IKB mold). In their research, design rules and expert knowledge of mold design were obtained from experienced mold designers and handbooks through various traditional knowledge acquisition processes. The traditional KBE approaches, such as RBR, CBR, and simple PDT have been successfully applied to mold cavity and runner layout design automation of the one product mold. Ye et al. [21] proposed a feature-based and object-oriented hierarchical representation and simplified symbolic geometry approach for automation mold assembly modeling. The previously mentioned analysis of various systems shows that authors used different ways to solve the problems of mold design by reducing it to mold configureator (selector). They used CAD/CAE integration for creating precision rules for mold-base selection. Many authors used CAE system for numerical simulation of injection molding to define parameters of injection molding. Several also developed original CAE modules for mold and injection molding process calculation. However, common to all previously mentioned systems is the lack of module for calculation of mold and injection molding parameters which would allow integration with the results of numerical simulation. This leads to conclusion that there is a need to create a software system which integrates parameters of injection molding with the result obtained by numericalFig. 4 Forms to determine the distance between the cooling channels and mold cavityFig. 5 Mold-base selector formssimulation of injection molding, mold calculation, and selection. All this would be integrated into CAD/CAE-integrated injection mold design system for plastic products.2 Structure of integrated CAD/CAE systemAs is well known, various computational approaches for supporting mold design systems of various authors use design automation techniques such as KBE (RBR, CBR, PDT) or design optimisation techniques such as traditional (NLP,LP, BB, GBA, IR, HR) or meta heuristic search such as (TS, SA, GA) and other special techniques such as (SPA, AR, ED).The developed interactive software system makes possible to perform: 3D modeling of the parts, analysis of part design and simulation model design, numerical simulation of injection molding, and mold design with required calculations.The system consists of four basic modules:& Module for CAD modeling of the part& Module for numerical simulation of injection molding processFig. 6 Form for mechanical mold calculation& Module for calculation of parameters of injection molding and mold design calculation and selection& Module for mold modeling (core and cavity design and design all residual mold components) The general structure of integrated injection mold design system for plastic products is shown in Fig. 1.2.1 Module for CAD modeling of the part (module I)The module for CAD modeling of the part is the first module within the integrated CAD/CAE system. This module is used for generating CAD model of the plastic product and appropriate simulation model. The result of this module is solid model of plastic part with all necessary geometrical and precision specifications. Precision specifications are: project name, number, feature ID, feature name, position of base point, code number of simulation annealing, trade material name, material grade, part tolerance, machine specification (name, clamping force, maximal pressure, dimensions of work piece), and number of cavity. If geometrical and precision specification is specified (given) with product model, the same are used as input to the nextmodule, while this module is used only to generate the simulation model.2.2 Module for numerical simulation of injection molding process (module II)Module II is used for numerical simulation of injection molding process. User implements an iterative simulation process for determining the mold ability parameters of injection molding and simulation model specification. The structure of this module is shown in Fig. 2.After a product model is imported and a polymer is selected from the plastic material database, user selects the best location for gating subsystem. The database contains rheological, thermal, and mechanical properties of plastic materials. User defines parameters of injection molding and picks the location for the gating subsystem. Further analyses are carried out: the plastic flow, fill time, injection pressure, pressure drop, flow front temperature, presence of weld line, presence of air traps, cooling quality, etc.The module offers four different types of mold flow analysis. Each analysis is aimed at solving specific problems:& Part analysis—This analysis is used to test a known gate location, material, and part geometry to verify that a part will have acceptable processing conditions.& Gate analysis—This analysis tests multiple gate locations and compares the analysis outputs to determine the optimal gate location.& Sink mark analysis—This analysis detects sink mark locations and depths to resolve cosmetic problems before the mold is built eliminating quality disputes that could arise between the molder and the customer.The most important parameters are the following: [22]& Part thickness& Flow length& Radius and drafts,& Thickness transitions& Part material& Location of gates& Number of gates& Mold temperature& Melt temperature& Injection pressure& Maximal injection molding machine pressureIn addition to the previously mentioned parameters of injection molding, the module shows following simulation results: welding line position, distribution of air traps, the distribution of injection molding pressure, shear stressFig. 7 Segment of the mechanical calculation algorithmdistribution, temperature distribution on the surface of the simulation model, the quality of filling of a simulation model, the quality of a simulation model from the standpoint of cooling, and time of injection molding [22, 23]. A part of output results from this module are the input data for thenext module. These output results are: material grade and material supplier, modulus of elasticity in the flow direction, modulus of elasticity transverse direction, injection pressure, ejection temperature, mold temperature, melting temperature, highest melting temperature thermoplastic, thermoplastic density in liquid and solid state, and maximum pressure of injection molding machine. During implementation of iterative SA procedure, user defines the moldability simulation model and the parameters of injection molding. All results are represented by different colors in the regions of the simulation model.2.3 Module for calculation of parameters of injection molding and mold design calculation and selection (module III)This module is used for analytical calculations, mold sizing, and its selection. Two of the more forms for determining the dimensions of core and cavity mold plates are shown in Fig. 3.Based on the dimensions of the simulation model and clamping force (Fig. 3) user selects the mold material and system calculates the width and length of core and cavity plates. Wall thickness between the mold cavity to the cooling channel can be calculated with the following three criteria: criterion allowable shear stress, allowable bending stress criterion, and the criterion of allowable angle isotherms are shown in Fig. 4 [22, 24]. The system adopts the maximum value of comparing the values of wall thickness calculated by previously mentioned criteria.Fig. 8 Forms for standard mold plates selectionFig. 9 Forms for mold plate model generationBased on the geometry of the simulation model, user select shape and mold type. Forms for the selection mold shape, type, and subsystems are shown in Fig. 5. Once these steps are completed, user implements the thermal, rheological, and mechanical calculation of mold specifications. An example of one of the several forms for mechanical mold calculation is shown in Fig. 6.Segment of the algorithm of mechanical calculations is shown in Fig. 7.f max maximal flexure of cavity platef dop allowed displacement of cavity plateε elastic deformationαmin minimal value of shrinkage factorE k modulus of elasticity of cavity plateG shear modulusS k wall thickness distance measuring between cavity and waterlined KT cooling channel diameterAfter the thermal, rheological, and mechanical calculations, user selects mold plates from the mold base. Form for the selection of standard mold plates is shown in Fig. 8. The system calculates the value of thickness of risers, fixed, and movable mold plates (Fig. 8). Based on the calculated dimensions, the system automatically adopts the first major standard value for the thickness of risers, movable, and fixed mold plate. Calculation of the thickness and the adoption of standard values are presented in the form as shown in Fig. 8.The interactive system recommends the required mold plates. The module loads dimensions from the database and generates a solid model of the plate. After the plate selection, the plate is automatically dimensioned, material plate isFig. 10 Structure of module IVassigned, and 3D model and 2D technical drawing are generated on demand. Dimensions of mold component (e.g., fixed plate) are shown in the form for mold plate mode generation, as shown inThe system loads the plate size required from the mold base. In this way, load up any other necessary standard mold plates that make up the mold subassembly. Subassembly mold model made up of instance plates are shown in Fig. 10Then get loaded other components of subsystems as shown in Fig. 5. Subsystem for selection other components include bolts and washers. The way of components selection are based on a production rules by authors and by company “D-M-E〞[25, 26].2.4 Module for mold modeling (core and cavity design and design all residual mold components; module IV)This module is used for CAD modeling of the mold (core and cavity design). This module uses additional software tools for automation creating core and cavity from simulation (reference) model including shrinkage factor of plastics material and automation splitting mold volumes of the fixed and movable plates. The structure of this module is shown in Fig. 11.Additional capability of this module consists of software tools for:& Applying a shrinkage that corresponds to design plastic part, geometry, and molding conditions, which are computed in module for numerical simulation& Make conceptual CAD model for nonstandard plates and mold components& Design impression, inserts, sand cores, sliders and other components that define a shape of molded part& Populate a mold assembly with standard components such as new developed mold base which consists of DME mold base and mold base of enterprises which use this system, and CAD modeling ejector pins, screws, and other components creating corresponding clearance holes& Create runners and waterlines, which dimensions was calculated in module for calculating of parameters of injection molding and mold design calculation and selection& Check interference of components during mold opening, and check the draft surfacesAfter applied dimensions and selection mold components, user loads 3D model of the fixed (core) and movable (cavity) plate. Geometry mold specifications, calculated in the previous module, are automatically integrated into this module, allowing it to generate the final mold assembly. Output from this module receives the complete mold model of the assembly as shown in Fig. 15. Thismodule allowsFig. 11 Subassembly model of moldFig. 12 CAD model of the test Productmodeling of nonstandard and standard mold components that are not contained in the mold base.3 Case studyThe complete theoretical framework of the CAD/CAE-integrated injection mold design system for plastic products was presented in the previous sections. In order to complete this review, the system was entirely tested on a real case study. The system was tested on few examples of similar plastic parts. Based on the general structure of the model of integrated CAD/CAE design system shown in Fig. 1, the authors tested the system on some concrete examples. One of the examples used for verification of the test model of the plastic part is shown in Fig. 12.The module for the numerical simulation of injection molding process defines the optimal location for setting gating subsystem. Dark blue regions indicate the optimal position for setting gating subsystem as shown in Fig. 13.Based on dimensions, shape, material of the case study product (Fig. 11), optimal gating subsystem location (Fig. 13), and injection molding parameters (Table 1), the simulation model shown in Fig. 14 was generated.One of the rules for defining simulation model gate for numerical simulation:IF (tunnel, plastic material, mass) THEN prediction dimension (upper tunnel, length, diameter1, diameter2, radius, angle, etc.)Part of the output results from module II, which are used in module III are shown in Table 1.Fig. 13 Optimal gating subsystem location in the partTable 1 Part of the output results from the module for the numerical simulation of injection molding processMaterial grade and material supplier Acrylonitrile butadiene styrene 780(ABS 780),Kumho Chemicals Inc.Max injection pressure 100 MPaMold temperature 60°C ili 40Melt Temperature 230°CInjection Time 0,39 s 0,2 sInjection Pressure 27,93 MPaRecommended ejection temperature 79°CModulus of elasticity, flow direction for ABS 780 2,600 MPaModulus of elasticity, transverse direction for ABS 780 2,600 MPaPoision ratio in all directions for ABS 780 0.38Shear modulus for ABS 780 942 MPaDensity in liquid state 0.94032 g/cm3Density in solid state 1.047 g/cm3In module III, the system calculates clamping force F=27.9 kN (Fig. 3), cooling channel diameter d KT=6 mm, cooling channel length lKT090 mm (Fig. 4). Given the shape and dimensions of the simulation model, square shape of mold with normal performance was selected as shown in Fig. 5. Selected mold assembly standard series: 1,616, length and width of mold housing 156×156 mm as shown in Fig. 8. In the segment of calculation shown in Fig. 8, mold design system panel recommends the following mold plates:& Top clamping plate N03-1616-20& Bottom clamping plate N04-1616-20& Fixed mold plate (core plate) N10A-1616-36& Movable plate (cavity plate) N10B-1616-36& Support plate N20-1616-26& Risers N30-1616-46& Ejector retainer plate N40-1616-10& Ejector plate N50-1616-12After finishing the fixed and movable mold plates from the standpoint of CAD modeling core and cavity plates, cooling channel, followed by manual selection of other mold standard components such as sprue bush, locating ring, guide pins, guide bush, leading bushing guide, spacer plates, screws (M4×10, M10×100, M10×30, M6×16, M10×30, etc.) and modeling nonstandard mold components (if any) ejector pins, ejector holes, inserts etc. A complete model of the mold assembly with tested simulation model is shown in Fig. 15.Fig. 14 Simulation model of plastic partFig. 15 Model of the mold assembly with tested simulation model4 ConclusionThe objective of this research was to develop a CAD/CAE integrated system for mold design which is based on Pro/ ENGINEER system and uses specially designed and developed modules for mold design. This paper presents a software solution for multiple cavity mold of identical molding parts, the so-called one product mold. The system is dedicated to design of normal types of molds for products whose length and width are substantially greater than product height, i.e., the system is customized for special requirements of mold manufacturers. The proposed system allows full control over CAD/CAE feature parameters which enables convenient and rapid mold modification. The described CAD/CAE modules are feature-based, parametric, based on solid models, and object oriented. The module for numerical simulation of injection molding allows the determination selection of injection molding parameters. The module for calculation of parameters of injection molding process and mold design calculation and selection improves design Fig. 15 Model of the mold assembly with tested simulation model faster, reduces mold design errors, and provides geometric and precision information necessary for complete mold design. The knowledge base of the system can be accessed by mold designers through interactive modules so that their own intelligence and experience can also be incorporated into the total mold design. Manufacture of the part confirms that the developed CAD/CAE system provides correct results and proves to be a confident software tool.Future research will be directed towards three main goals. The first is to develop a system for automation of family mold design. Another line of research is the integration with CAPP system for plastic injection molds manufacturing developed at the Faculty of Technical Sciences. Finally, following current trends in this area, a collaborative system using web technologies and blackboard architecture shall be designed and implemented.塑料制品的CAD / CAE集成的注塑模具设计系统摘要：模具设计是一个知识密集的过程。
注射注塑模具外文翻译外文文献翻译、中英文翻译、外文翻译
外文资料翻译系部：专业：姓名：学号：外文出处：dvanced English literacy course（用外文写）附件：指导老师评语签名：年月日第一篇译文（中文）2.3注射模2.3.1注射模塑注塑主要用于热塑性制件的生产，它也是最古老的塑料成型方式之一。
目前，注塑占所有塑料树脂消费的30%。
典型的注塑产品主要有杯子器具、容器、机架、工具手柄、旋钮（球形捏手）、电器和通讯部件（如电话接收器），玩具和铅管制造装置。
聚合物熔体因其较高的分子质量而具有很高的粘性；它们不能像金属一样在重力流的作用下直接被倒入模具中，而是需要在高压的作用下强行注入模具中。
因此当一个金属铸件的机械性能主要由模壁热传递的速率决定，这决定了最终铸件的晶粒度和纤维取向，也决定了注塑时熔体注入时的高压产生强大的剪切力是物料中分子取向的主要决定力量。
由此所知，成品的机械性能主要受注射条件和在模具中的冷却条件影响。
注塑已经被应用于热塑性塑料和热固性塑料、泡沫部分，而且也已经被改良用于生产反应注塑过程，在此过程中，一个热固树脂系统的两个组成部分在模具中同时被注射填充，然后迅速聚合。
然而大多数注塑被用热塑性塑料上，接下来的讨论就集中在这样的模具上。
典型的注塑周期或流程包括五个阶段（见图2-1）：（1）注射或模具填充；（2）填充或压紧；（3）定型；（4）冷却；（5）零件顶出。
图2-1 注塑流程塑料芯块（或粉末）被装入进料斗，穿过一条在注射料筒中通过旋转螺杆的作用下塑料芯块（或粉末）被向前推进的通道。
螺杆的旋转迫使这些芯块在高压下对抗使它们受热融化的料筒加热壁。
加热温度在265至500华氏度之间。
随着压力增强，旋转螺杆被推向后压直到积累了足够的塑料能够发射。
注射活塞迫使熔融塑料从料筒，通过喷嘴、浇口和流道系统，最后进入模具型腔。
在注塑过程中，模具型腔被完全充满。
当塑料接触冰冷的模具表面，便迅速固化形成表层。
由于型芯还处于熔融状态，塑料流经型芯来完成模具的填充。
塑料模具设计中英文翻译006资料
xxxxx大学毕业设计（论文）外文文献学院 xxxxxxxxxxx专业班级 xxxxxxxxxxxxx 学生姓名 xxxxxxxxxxxxxxx指导教师 xxxxxxxxxxxxxxxA. Mold ComponetsMolds used in injection molding consist of two halves; one stationary and one movable. The stationary half is fastened directly to the stationary platen and is in direct contact with the nozzle of the injection unit during operation. The movable half of the mold is secured to the movable platen and usually contains the ejector mechanism. There are many possible mold designa, including multiple piece molds for complicated parts. On production molding equipment many articles may be shot at the same time by the use of multiple cavity molds. The use of a balanced runner system carries the plastic from the sprue to each individual cavity. At this poin the material passes through a gate into the cavity. The gate is a restriction, smaller then the runner, to provide for even filling of the mold cavity and to allow the products to be easily removed form the runner system. With most injection molding system, the articles can be snapped away from the runner or sprue without additional trimming. Prouducts that have been injection molded can usually be identified by finding where the gate was broken off. The gate will usually be located at the edge or parting line of an object or in the center of cylindrical product.Molds are expensive, as are the machines. Yet, once the product has been designed, molds made, and production stared, articles can be produced in quantity at low cost. Virtually all thermoplastics can be injection molded through variations in mold and machine design.Mold (and die) parts that are mass-produced and standardized in shape and dimension are referred to as “standards” (or “standard parts”). Specialized operators of milling machines, lathes, lathes, electronic discharge machining (EDN) equipment and grinders produce mold components independently of each other, following detaied mold part drawings. Finally, all these items come together with the standard mold base and hardware and are assembled by the mold maker. Today, standard components for the moldmaking industry are marketed by a number of companies. Fig.3.1.1 illustrate the standard components for Molds.Table 3.1.1 Status of standardization (1998) components forCompression, Injection, and Die-Cast MoldB Mold ConstructionThe construction of the mold for injection molding begins with the working drawing. From it the tequirements for the mold can be specified. These would include the material from which the mold should be made, the availability of equipment for machining the mold, and the mold capacity of the die set on the machine.Cold rolled steel is an ideal material for laboratory molds, since it machines well, is fairly inexpensive, and holds up well for nozzle pressure and wear. Its major disadvantage is that it will rust quickly unless protected by mold telease or wax during storage. ComplicatedXxx大学mold cavities need specialized machining and polishing, therefore, circular cavities which can be turned and polished on the lathe require less equipment and machining skill.Similar molds may also be machined from aluminum, and they have the advantage of not rusting. Excessive wear develops on the sprue due to the high nozzle pressure on the soft aluminum, but this can be overcome by the use of a steel cover plate on the top of the mold.Another method of mold construction is by the casting process using an aluminum filled epoxy resin. This type of mold is particularly suited to products of intricate design and products that are difficult to machine. The cast epoxy is strong and gives good surface detail, however, it is brittle and should have a steel top plate attached to absorb the wear of the nozzle. A pattern of the product must be secured or made and placed on a mold plate. The drag of a small steel flask is placed around the pattern and the epoxy resin is poured to fill the mold half. When this half of the mold has been cured, the cope is placed over it and the remainder of the mold poured. Upon curing, the flask is removed, all surfaces machined smooth, dowel pinholes drilled, and dowels inserted. A steel cap plate should be bolted to the top halves and the sprue, runners, and gates machined. Instructions for mixing, pouring, and curing the aluminum filled epoxy should be followed according to the manufacturer’s specifications.2. Hot Runner SystemsHot runners are classified according as they are heated: insulated-runner systems (it is not described in this article) and genuine hot-runner systems.The latter can be further sub-classified according to the type of heating: internal heating, and external heating.Heating is basically performed electrically by cartridge heaters, heating rods, band heaters, heating pipes and coils, etc. To ensure uniform flow and distribution of the melt, usually a relatively elaborate aontrol system comprising several heating circuits and an appropriate number of sensors is needed. The operating voltage is usually 220 V to 240 V, but small nozzles frequently have a low voltage of 5 V, and also 15 V and 24 V operating voltage.Runner systems in conventional molds have the same temperature level as the rest of the mold because they are in the same mold block. If, however, the runner system is located in a special manifold that is heated to the temperature of the melt, all the advantages listed below accrue. Runner manifolds heated to melt temperature have the task of distributing the malt as far as the gates without damage. They are used for all injectionmolded thermoplastics as well as for crosslinking plastics, such as elastomers and thermosets.Xxxx大学In the case of thermoplastics, these manifolds are usually referred to as the hot-runner system, the hot manifold, or simply as hot runners. For crosslinking plastics, they are known as cold runners.A. Hot-Runner SystemsHot-runner systems have more or less become established for highly-automated production of molded thermoplatic parts that are produced in large numbers. The decision to use them is almost always based on economics, i. e. production size. Quality considerations, which played a major role in the past, are very rare now because thermoplastics employed today are almost all so that they can be processed without difficulty with hot-tunner systems that have been adapted accordingly.Hot-tunner systems are available as standard units and it is hardly worthwhile having them made. The relevant suppliers offer not only proven parts but also complete systems tailored to specific needs. The choice of individual parts is large.B. Economic Advantages and Disadvantages of Hot-Runner Systems1. Economic AdvantagesSavings in materials and costs for regrind.Shorter cycles; cooling time no longer determined by the slowly solidifying runners; no nozzle retraction required.Machines can be smaller because the shot volume-around the runners-is reduced, and the clamping forces are smaller because the runners do not generate reactive forces since the blocks and the manifold block are closed.2. Economic DisadvantagesMuch more complicated and considerably more expensive.More work involved in running the mold for the first time.More susceptible to breakdowns, higher maintenance costs (leakage, failure of heating elements, and wear caused by filled materials).3. Technological AdvantagesProcess can be automated (demolding) because do not need to be demolded.Gates at the best position; thanks to uniform, precisely controlled cooling of the gate system, long tlow paths are possible.Pressure losses minimized, since the diameter of the runners is not restricted.Artificial balancing of the gate system; balancing can be performed during running production by means of temperature control or special mechanical system (e. g. adjustment of the gap in a ring-shaped die or use of plates in flow channel. Natural balancing is better).Selective influencing of mold filling; needle valve nozzles and selective actuation ofXxx大学them pave the way for new technology (cascade gate system: avoidance of flow lines, in-mold decoration).Shorter opening stroke needed compared with competing, conventional three-platen molds.Longer holding pressure, which leads to less shrinkage.4. Technological DisadvantagesRisk of thermal damage to sensitive materials because of long flow paths and dwell times, especially on long cycles.Elaborate temperature control required because non-uniform temperature control would cause different melt temperatures and thus non-uniform filling.C. Design of a Hot-Runner System and its ComponentsHot-runner molds are ambitious systems in a technological sense that involve high technical and financial outlay for meeting their main function of conveying melt to the gate without damage to the material.D. Externally/Internally Heated SystemsThe major advantages and disadvantages of the two types .E. Externally Heated System1. AdvantageLarge flow channel cause low flow rare and uniform temperature distribution.2. DisadvantageThe temperatures required for external heating have to be very much higher. For PA 66, for example, the mold temperature is approximately 100℃and the manifold temperature is at a temperature difference of approximately 170℃from the mold block, which means.Special measures required for fixing the hot-runner nozzles to the gates because of the considerable themal expansion.Risk of disruption if this is not adepantely resolved.Higher heating power (over 500 W per 100 mm line for a typical cross-section measuring 40·7mm2).Insulation from the mold block.Large ,unsupported ateas and therefore, with large-surface molds, risk of bowing of the mold platen on the feed side if this has not been designed thick enough and thus, as a direct consequence, the mold becomes very heavy.F. Internally Heated SystemA frozen layer of plastic forms on the inner surface of the channel and functions as anXxxx大学insulation layer.The heat requirement of the system is much lower (toughly 55 W per 100 mm length of inside tube).The temperature differences between mold and manifold blocks are negligible; therefore measures that would have been necessary for large heat expansion are not needed.The hot manifold of an internally heated system if a compact block that is bolted tightly to mold. Consequently, the mold is very rigid and no measures are required for centering the nozzles and gates. This also allows the plate on the machine side to be manufactured as one block consisting of fixed mold with inbuilt manifold and corresponding rigidity.The melt volume is small and so the dwell times of the flowing melt are short. On the other hand, the flow rates are very much greater and this can damage the material. It is not advisable to use internally heated systems for sensitive materials. When deciding on a certain system, advice can be obtained from suppliers.3.Forming TheoryThe confidence level in successfully forming a sheetmetal stamping increases as the simplicity of the part's topography increases. The goal of forming with stamping technologies is to produce stampings with complexgeometric surfaces that are dimensionally accurate and repeatable with a certain straindistribution, yet free from wrinkles and splits. Stampings have one or more forming modes that create the desired geometries. These modes are bending, stretch forming and drawing. Stretching the sheetmetal forms depressions or embossments. Drawing compresses material circumferentially to create stampings such as beer cans.As the surfaces of the stamping become more complex, more than one mode of forming will be required. In fact, many stampings have bend, stretch and draw features produced in the form die. The common types of dies that shape material are solid form, stretch form and draw.Solid Form The most basic type of die used to shape material is the solid form die. This tool simply displaces material via a solid punch "crashing" the material into a solid die steel on the press downstroke. The result is a stamping with uncontrolled material flow in terms of strain distribution. Since "loose metal" is present on the stamping, caused by uncontrolled material flow, the part tends to be dimensionally and structurally unstable.Stretch Form Forming operations that provide for material flow control do so with a blankholder. The blankholder is a pressurized device that is guided and retained within the dieXxx大学set. Stampings formed with a blankholder may bedescribed as having three parts, shown in Fig. 1. Theyaretheproductsurface(shown in red), blankholder surface (flat area shown in blue) and a wall that bridges the two together. The theoretical corner on the wall at the punch is called the punch break. The punch opening is the theoretical intersection at the bottom of the draw wall with the blankholder. The male punch is housed inside the punch opening, whereas the blankholder is located around the punch outside the punch opening. These tools have a one-piece upper member that contacts both the b- lankholder and punch surfaces. A blank or strip of material is fed onto the blankholder and into location gauges. On the press downstroke, the upper die member contacts the sheet and forms a lock step or bead around the outside perimeter of the punch opening on the blankholder surface to prevent material flow off the blankholder into the punch. The blankholder then begins to collapse and material stretches and compresses until it takes the shape of the lower punch. The die actions reverse on the press upstroke, and the formed stamping is removed from the die.Draw The draw die has earned its name not from the mode of deformation, but from the fact that the material runs in or draws off the blankholder surface and into the punch. Although the draw mode of deformation is present in draw dies, some degree of the stretch forming and bending modes generally also are present. The architecture and operational sequence for draw dies is the same as stretch-form dies with one exception. Material flow off the blankholder in draw dies needs to be restrained more in some areas than others to prevent wrinkling. This is achieved by forming halfmoon-shaped beads instead of lock steps or beads found in stretch-form dies. The first stage of drawing sheetmetal, after the blank or strip stock has been loaded into the die, is initial contact of the die steel with the blank and blankholder. The blank, round for cylindrical shells to allow for a circumferential reduction in diameter, is firmly gripped all around its perimeter prior to any material flow. As the press ram continues downward,the sheetmetal bends over the die radius and around the punch radius. The sheetmetal begins to conform to the geometry of the punch.Very little movement or compression at the blank edge has occurred to this point in the drawing operation. Air trapped in the pockets on the die steel is released on the press downstroke through air vents.The die radius should be between four and 10 times sheet thickness to prevent wrinkles and splits.Straightening of sheetmetal occurs next as the die continues to close. Material that was bent over the die radius is straightened to form the draw wall. Material on the blankholder now is fed into the cavity and bent over the die radius to allow for straightening without fracture. The die radius should be between four and 10 times sheet thickness to preventXxxx大学wrinkles and splits. The compressive feeding or pulling of the blank circumferentially toward the punch and die cavity is called drawing. The draw action involves friction, compression and tension. Enough force must be present in drawing to overcome the static friction between the blank and blankholder surfaces. Additional force is necessary during the drawing stage to overcome sliding or dynamic friction and to bend and unbend the sheet from the blankholder surface to the draw wall. As the blank is drawn into the punch, the sheetmetal bends around the die radius and straightens at the draw wall.To allow for the flow of material, the blank is compressed. Compressionincreases away from the die radius in the direction of material flow because there is more surface area of sheetmetal to be squeezed. Consequently, the material on the blankholder surface becomes thicker.The tension causes the draw wall to become thinner. In some cases, the tension causes the draw wall to curl or bow outward. The thinnest area of the sheet is at the punch radius, and gradually tapers thicker from the shock line to the die radius. This is a probable failure site because the material on the punch has been work-hardened the least, making it weaker than the strain hardened material. The drawing stage continues until the press is at bottom dead center. With the operation now complete, the die opens and the blankholder travels upward to strip the drawn stamping off of the punch. Air vents provided inflat or female cavities of the punch allow air to travel under the material asit is lifted by the blankholder. The stamping will have a tendency to turn inside out due to vacuum in the absenceof air vents.4.Injection mold designThe plastic injection mold is in the present all plastics mold，uses the broadest mold, can take shape the complex high accuracy，plastic product. Under only is sketchily introduces.The design plastic injection mold first must have the certain，understanding to the plastic, the plastic principal constituent is a polymer. Like we often said the ABS plastic then is the propylene nitrile, the pyprolylene, the styrene three kind of monomers uses the emulsion, the main body or aerosol gathers the legitimate production,enable it to have three kind of monomers the high performance and may the compression molding, injects under the certain temperature and the pressure to the mold cavity, has the flow distortion, the obtaining cavity shape, after guarantees presses cooling to go against becomes the plastic product. The polymer member assumes the chain shape structure generally, the linear molecule chain and a chain molecule thought is the thermoplastic, may heat up the cooling processing repeatedly, but passes through heats up many members to occur hands over the association response,Xxx大学including forms netted the build molecular structure plastic usually is this, cannot duplicate injects the processing, also is the thermosetting plastics which said.Since is the chain shape structure, that plastic when processing contracts the direction also is with the polymer molecular chain under the stress function the orientation and the cooling contraction related, must be more than in the flow direction contraction its vertical direction in contraction. The product contraction also with the product shape, the runner, the temperature,guarantees presses factor and so on time and internal stress concerns.In the usual book provides the shrinkage scope is broad, considers is product wall thickness, the structure and the determination casts the temperature pressure size when the practical application and the orientation. The common product if does not have the core strut, the contraction correspondingly wants big. The plastic casts the mold basically to divide into the static mold and to move the mold.In the injection molding machine injection one side belt runner set is the static mold, the static mold has the runner wrap, the back, the template composition generally, the simple mold (is specially static mold does not have core mold) also to be possible not to use the back, straight took over the use of the thick template to be possible. The runner set is a standard letter generally, only if the special reason, does not suggest the cancellation. A runner set of use is advantageous in installs the mold, the replacement is convenient, does not need oneself to polish. Some special molds runner wrap may use to drill or with the taper line shears. When the partial molds must the static mold drawing of patterns, but also must add on the static mold drawing of patterns organization. Moves the mold the structure for to move the template generally, to move the mold back, the drawing of patterns organization as well as the mold foot and the installing equipment dead plate.In the drawing of patterns organization except escapes the material pole, but also has the position pole, the partial molds also must increase the spring by to realize for example function and so on automatic drawing of patterns. Also has the guide pillar, the cooling water pore, the flow channel and so on also is may not the few molds basic structure. Certainly, slanting leads the mold also to have slanting leads the box, the slanting guide pillar and so on. When is a product design mold, first must establish the mold the basic structure size by to prepare materials, speeds up the speed which the mold makes. The complex product should draw up the good product chart first, then arranges the mold the size. The present mold basically must carry on the heat treatment, raises the mold degree of hardness,enhances the mold service life. In front of the heat treatment,carries on the roughing first to the template: Drills the guide pillar hole, returns to the position hole (to move mold), the cavity hole,the screw aperture, a runner set of hole (static mold), pulls the material hole (to move mold), thecooling water pore and so on, the mill good flow channel, the cavity, some molds also should the mill good slanting lead the box and so on. The present ordinary precision mold template uses Cr12, Cr12Mov and some specialized molding tool steels generally,Degree of hardness and so on Cr12 cannot too be high, when HRC60 cracks frequently, template commonly used degree of hardness is about generally HRC55. Core degree of hardness may above HRC58. If the material is 3Cr2W8v, after the manufacture the again nitriding skin hardness, degree of hardness should be above HRC58, the nitrided level should thicker be better. The runner relates directly to models artistic, the runner design not good speech, is easy to have the flaw. In any has not prevented in the situation is very easy to produce the snake class. Regarding requests the high product, but also should design the overflow and the exhaust. The overflow place may use the roof bar, do not have the overflow edge on the template, only then not as for influence mold life.The design mold software more and more are also many, majority has very little used the pencil to draw up the mold chart.When design, if does not have the product chart, is very difficult in the complex mold chart to display the software charting the strong point. After the product chart draws up keeps a copy, again produces the manufacture graph using the size actuation or the proportion reproduce by pantograph. The blueprint preservation also is important, the most direct method is prints to be possible the long time preservation, but cannot revise; The preservation is does not have the safeguard in the floppy disk, possibly tomorrow will leave "" prompt and so on formatted "; The hard disk also is the expendable items, has problems as necessary; If has engraves recording machine to be best, engraves on the compact disc may; Now the network also has provided for us conveniently, causes your blueprint to be possible to preserve in world any place, looks like network hard disk performance and so on the myspace is stable, operation simple, the 300M space no matter what you use, but domestic I have used the hypothesized hard disk is not good, you have saved the thing obviously, it and so on refuses by "database connection wrong" to acknowledge actually. Must remind: The server also can appear the breakdown, preserves in oneself stand either the network hard disk data must at least in two stands or two national different websites, if your data needs to keep secret, you cannot keep secret the technology, that exempted!5. ABS AND PCABS engineering plastics polycarbonate (PC) more PC performance superiority, but its price is too high;Yakeli transparency best, but its Nairongji sexual deviation and impatienceshocks;ABS transparent lack of transparency;K- resins and more transparent soft, hardness too low. Z- polyester and high transparency, luster degrees high, particularly high resilience, high impact performance superiority, bending without evidence, chemical resistant outstanding performance, good liquidity, color resistant, easy processing shaped many advantages may replace PC, transparent acrylic, Yakeli, K- resins and other raw materials, and price more reasonable, transparent processing is the preferred target material.Z- polyester table for comparison with other commonly used plastic :Z-polymer Yakeli K- resins tabs PCZ-6008 Z-6006 Z-6002/4transparency (%) 91 92 90 70 68high impact J/m, 23 degrees 860 360 90 60 130 800-1000fracture productivity (%) 330 310 270 20 50 120bending modules volume, hydraulically 1800 1900 1800 2800 2300 2400ABS engineering plasticsABS resin is the reaction (a), butadiene (B) and chemical (S) of the copolymer three monomer, acrylic styrene resins maintained excellent performance of the processing shaped sexual vulnerability, and increase flexibility, strength (butadiene identity), corrosive resistant and tolerant (reaction fine performance), and high surface hardness, chemical resistance is good. at the same time by changing the ratio of the three above-mentioned group, the performance can be compared to change, the ABS engineering plastics broad use, mainly for mechanical, electrical, textile, automobile and shipbuilding industries.Polycarbonate (PC)Liquid is a new type of engineering plastics softer, softer performance of a fine motor insulation and mechanical properties, especially resistance to the most outstanding performance and high resilience, allowing the use of a broad temperature range (-100~130 degrees), transparent (as "transparent metal"), non-toxic, processing shaped convenience. It will not only replace some metal, but also alternative glass, timber. In recent years softer rapid development in machinery, automobile, aircraft, instrumentation, electrical, and other trades have a wide range of applications.ABS plasticABS plastic chemical name : acrylonitrile-butadiene - styrene copolymer English name : Acrylonitrile Butadiene Styrene weight : 1.05 grams / cubic shaped contraction rate : 0.4-0.7% shaped temperature : 200-240 degrees dry conditions : 80-90 degrees 2 hours features : 1, integrated performance better, higher impact strength, chemical stability, good call performance.2, and 372 plexiglass Rongjie of the good produced growing fast in recentinaugural pieces, and may surface chromium plating, painting.3, Gaokangchong, high heat, fire, enhancement, transparency level. 4, mobility than hips went over PMMA, PC, and other good, good flexibility. Uses : suitable for the production of general machinery parts, reduced friction wear-resisting parts, transmission parts, and telecommunications components.Shaped characteristics : 1.Amorphous materials, the mobile medium, large moisture absorption must be fully dry surface for the playing pieces luster to prolonged dry preheat 80-90 degrees, three hours.2.Are advised to take high-temperature materials, high-temperature state, but Liu Wen Yi excessive decomposition (decomposition temperature >270 degrees).More pieces of high precision, Mo Wenyi from 50-60 degrees high luster.More pieces of heat, called Wenyi from 60-80 degrees.3, seeking to resolve clip front, the need to improve the mobility of materials to take high Liu Wen, high-temperature modules, or changes in water level and other methods. 4, such as taking class or fire resistant material level, production will hold 3-7 days molding plastic decomposition from the surface, leading to mould surface illuminated, the need for timely warning screen, while additional exhaust components surface location.ABS resin production is the largest, most extensive polymer applications, the performance will PS,SAN,BS organically unified, both tough, hard, just as a fine mechanics performance. ABS is acrylonitrile, butadiene and styrene copolymer of 3.0 a representative reaction, B representative butadiene, styrene s representatives. ABS engineering plastics are generally opaque, appearance Chengqianxiangyashai, non-toxic, tasteless, commercial fasteners, hardware, just character, burning slow, a yellow flame, smoke, the burning of plastic softened, char, a special cinnamon smell, but no meltdown jumped phenomenon. ABS engineering plastics with excellent integrated performance, excellent impact strength, good size stability, electricity performance, resistance to abrasion, chemicals resisting sexual, Ransexing, shaped processing and mechanical processing better. Naishui ABS resins, inorganic salt, alkali and acids, Chunlei not dissolve in most solvents and hydrocarbons category, and easily dissolve in aldehyde, ketone, ester and certain polychlorinated hydrocarbons. ABS engineering plastics shortcomings : low thermal deformation temperature, flammable, Naihou sexual poor.Plastic injection molding plastic mouldPlastic injection molding plastic mould is now all the most widely used instrument to shape complex high-precision plastic products. This is only a rough description.Plastic injection mould design at the outset to have some understanding of plastic, the plastic is a major component of polymer. As we often say that the reaction is ABS plastic, butadiene, styrene monomer used three tanks, identity or suspended gather legitimate。
外文原文(注塑模具设计文献翻译)
Effect of gate size on the melt filling behavior and residual stress of injection moldedpartsPengcheng Xie a ,Fengxia Guo a ,Zhiwei Jiao a ,Yumei Ding a ,Weimin Yang a ,b ,⇑a College of Mechanical and Electrical Engineering,Beijing University of Chemical Technology,Beijing 100029,ChinabState Key Laboratory of Organic–Inorganic Composites,Beijing University of Chemical Technology,Beijing 100029,Chinaa r t i c l e i n f o Article history:Received 8March 2013Accepted 28June 2013Available online 20July 2013Keywords:MoldingVisualization Flow behavior Residual stressa b s t r a c tThis paper studies the effects of gate size on the cavity filling pattern and residual stress of injection molded parts.A total of three rectangular gates with different sizes were used.Experiments were carried out by using a dynamic visualization system.A flow visualization mold was specially designed and made for this study.A high-speed video camera was used to record the mold filling phenomena of cavities with different gate size and different processing parameters.In addition,a Stress Viewer was used to charac-terize the residual stress of molded samples.It was found that the undersized gate has many adverse effects on the filling behavior and residual stress of molded parts.With a larger gate,the cavity will be filled faster and residual stress of parts may be smaller.The result of the study also indicates that nozzle temperature and injection rate can significantly affect the above two aspects.Ó2013Elsevier Ltd.All rights reserved.1.IntroductionGating system design is a key link in the process of injection mold design,because as a channel to connect the runner and the cavity,the gate plays a very important role.The design of gate not only affects the melt filling process,but also concerns the demolding process and separation of products and waste,thus affecting the production costs and benefits [1].Gate size as an essential aspect of gate design has very important influence on the quality of part.A gate with suitable dimension should be able to ensure the plastic filling with fast speed and good liquidity [2].And at the packing stage,gate must remain open long enough to inject additional material into the cavity for shrinkage-compensating.Generally,the gate size is established by experience.Cross-sec-tion of gate is typically smaller than that of the runner and parts,thus parts can be easily separated from the runner without leaving a visible scar on the part.In addition,when the material in the gate drops below the freeze temperature,there is the end of packing,therefore,the gate dimension controls the packing time.From these points of view,the overlarge gate is not desirable.In recent years,a large number of studies on gate design were carried out.But there are limited published works on studies relat-ing to design of gate size:Tor et al.[2]used five rectangular gateswith different ratio of width and depth to the impacts of gate size on the quality of powder injection molding.By performing the analysis of weight and density on the samples molded for each of the five gates,they evaluated the impact of different gate size.Shen et al.[3]analyzed the optimal gate design of thin-walled injection molding by using control volume finite element method.Xie and Ziegmann [4]investigated the effect of gate dimension on micro injection molded weld line strength with polypropylene (PP)and high-density polyethylene (HDPE)and found out some relation-ship between gate size and the quality of micro-molded part.This paper aims to intuitively display the influence of gate size on melt flow behavior in cavity,as well as the relationship between gate size and residual stress of parts.As moldings are used in wider areas,higher requirements for precision of products have been constantly put forward.How to suppress the generation of product defects (e.g.jet,weld lines,air bubbles,flash,crazing,etc.)and maximize the dimensional accuracy of products has been an important subject for researchers.Observing the flow behavior as an effective method could help people know the generation princi-ple of defects,and further to find out the causes and even the solu-tions [5].The emergence of visualization injection molding method applied an effective way for observing the phenomenon of melt flow in the mold.Injection molding visualization technology is a technology that the injection molding process can be directly ob-served.It is essentially adding a system that can real-time monitor-ing the filling process and reproducing the melt flow behavior in a conventional injection molding process,thus making the injection molding process from the traditional sense of ‘‘invisible’’becomes ‘‘visualization’’and ‘‘repeatable’’.Up to now,visualization method0261-3069/$-see front matter Ó2013Elsevier Ltd.All rights reserved./10.1016/j.matdes.2013.06.071⇑Corresponding author at:College of Mechanical and Electrical Engineering,Beijing University of Chemical Technology,Beijing 100029,China.Tel./fax:+861064434734.E-mail address:yangwm@ (W.M Yang).has been widely used in multiple studies of injection.Yokoi has carried out a lot of research by this technique,for example,the study of molding process of two-color products,observation of flow front behavior duringfilling process with two-axis tracking system,analysis of thermoset phenolic resinflow behavior by Gate-Magnetization Method,and the study of meltfilling disci-pline of ultra-high speed injection molding[6–10],etc.In addition, by this method,Liu and Wu[11]compared the difference offilling process and molding parts between water-assisted and gas-as-sisted injection molding.Mehdi et al.[12]studied the bubbledynamics in foam injection molding.However,the visualization technology being applied to the gate size has not yet been found, in view of the successful application of it in above-mentioned areas,as well as the significant advantage it had shown,this study will use visualization techniques as one of the main means of research.Besides,defects in the products,such as warping and shrinkage, are detrimental to the quality and accuracy of the products[13]. Actually,an important factor causing these defects is residual stress.In general,the residual stress of injection molded products are divided into two Categories.One is the thermal residual stress, which is resulting during cooling period in the mold and after demolding[14].The other one is referred as residualflow stresses, which is due to the shear and normal stresses duringfilling and packing.Flow-induced stress is smaller than the former,but it could induce anisotropy of optical and some mechanical properties because of different molecular orientation in the directions of par-allel and perpendicular to theflow direction[15].Residual stress is not only the main cause of dimensional and shape inaccuracies of molded parts,but also responsible for environmental stress crack-ing[16,17].The dimension of gate influences the orientation of polymer molecule,fibers,and the mechanical and physical proper-ties of molding parts[18,19].Therefore,through comparing the residual stress of the products can provide the basis for the choice of gate size.Residual birefringence could be a valid measuring method for the polymer molecular orientation and residual stress [20],but it also can reflect a microscopic morphological structure of polymer products[21].Friedl[22]considered that the refractive index essentially contains all the information ofstatus characteristics of transparent injection products.In this paper,the visualization method was used toflow behavior in the case of different gate size.Throughthe differences offlow behavior with three gates underof injection parameters,the relationship between gatemeltfilling process will be drawn.And then,be used to measure the residual stresses in the molding experiment will be performed by Photo-elastic,whicheffect that the induced stresses inside a material willincoming light and form an interaction pattern.Thisbe related to the stress level and distribution inside the2.Experimental procedureThe injection experiment was conducted by the means injection molding.The emergence of visualizationing method applied an effective way for observing thenon of meltflow in the mold[5].The visual systemstudy including a injection molding machine,a visual mold,a high speed camera,a light and a data acquisition device.2.1.MaterialMaterial used in this study is an injection molding graded Polypropylene(PP,ST868M,from Chemical LCY,Taiwan),which is a random copolymer with ultra-high transparency,and its properties are listed in Table1.The recommended processing temperature ranges of190–270°C and the mold temperature is recommended between20and50°C.2.2.Part geometry and mold designThe mold cavity used in this paper is a tensile specimen with single gate.The geometries and dimensions of the tensile speci-mens were shown in Fig.1,which were designed and manufac-tured according to ISO527-2:2012[23].The gate of cavity is replaceable,three gates with different dimensions have been adopted in the experiment.Concretely,those gates have the same length(2mm)but different width and depth.According to the cross section size,they were respectively named as gate S(small), gate M(middle)and gate L(large),the actual sizes are shown in Ta-ble2.The middle gate size was selected based on experience val-ues,and then as the standard.The length and width of small gate and large gate were proportional changed and rounded.In order to facilitate the comparison,the small gate was made as small as possible,the cross-sectional edge length was as1/3times as the middle gate and into an integer of1Â1.Meanwhile,the large gate was expanded by the ratio of4/3times as the gate M,andfinal rounded to4Â3.Fig.2shows the photo of cavity plate used in the study,the cav-ity is processed on a removable patch,which could be tightly pressed on thefixed mold plate by positive pressure.When replac-ing the mold,people just need to loosen the screw then the embed-Table1General property of PP used in this study.Property Unit Globalene ST868M Density g/cm30.899MFI(meltflow rate)g/10cm18(230/2.16)Shrinkage% 1.3Tensile stress at yield MPa28Tensile strain at yield%12Heat deflection temperature°C88Table2Gate dimensions used in the experimental mold.Gate Small Middle Large Width(mm)134Depth(mm)1 2.53Length(mm)222Fig.1.Dimensions of tensile specimen.P.Xie et al./Materials and Design53(2014)366–372367the plastic molding processing is carried out in a closed flow chan-nel and cavity,the process of melt,mold filling,solidification and cooling are all invisible.Different to the conventional mold whose cavity is surrounded by metal,visual mold changed the cavity wall on the moving platen into a transparent quartz glass,and placed a mirror at a 45°angle in the other side of the glass.By the reflection of light,the phenomenon in the cavity can be observed from the outside.The rectangle in Fig.2shows the area that could be seen through the monitoring window.As shown in the figure,the length of monitoring window is smaller than the length of the article,so it to see the complete filling process through study.Fig.3shows the mold schematic.the melt filling process is nearly a transient the process to be seen by the naked eye This paper used a high-speed camera whose reach 17,500frames per second,and each moment of the filling process could be recorded clearly by it.The devices of visualization experiment are shown in Fig.4.2.3.Injection moldingAll specimens were prepared on an electric injection molding machine (GSK AE80).The maximum clamping force is 80tons,screw diameter is 32mm.The maximum injection velocity and volume can be provided is 300mm/s and 101cm 3.During the course of the experiment,corresponding to each set of experimen-tal parameters with different gates,more than 10shots were made before shooting to ensure that the process was stable.If no signifi-cation variation was observed during these runs,high-speed cam-era would be used to capture the melt filling process.Each set of parameters was shot five times,and the five specimens were col-lected for internal stress test.Table 3shows the experimental parameters and corresponding number.The packing pressure was always set to 80%of injection pressure,and packing time was 5s.The melting temperature was 240°C and mold tempera-ture was constantly at 35°C,original nozzle temperature was 190°C.3.Results discussion and analysis 3.1.Filling behaviorFig.5shows the flow behavior of melt front in the case of parameter (5)with gate S.In the initial stage of melt into the cav-ity,a small amount of material was straightly injected into the cav-ity and jetting occurred.And because of the decrease of temperature,the viscosity increased and the fluidity is reduced after the melt had flown through channel to the gate,a temporary filling hysteresis generated.Until a large enough pressure had been gradually built up,the low-temperature melt would be promoted into the cavity and moved forward,then the subsequent melt would flow smoothly through the gate and fill the cavity at a high-er speed.During the experiment process,it was found that sometimes the products obtained with gate S may be not fully formed,and increasing the rate and injection pressure can not completely solve the problem.The main reason is that the material in gate S had fro-zen before the cavity was filled completely.In order to obtain the full filled specimen,the method of improving the nozzle tempera-ture was tried,and the results showed that the nozzle temperature was a significant impact factor on the filling volume of small gate cavity.Fig.6is the filling volume of the parts shaped in the case of different injection pressure and nozzle temperature,it is obvious that the higher temperature of the nozzle,the greater the filling volume.The reason is that if the nozzle temperature is increased,the temperature of melt near the small gate will rise,thereby extending the gate solidification time,so that the melt filling quan-tity increases.Besides,increasing the injection pressure can also help to improve the filling volume.When using gate M and gate L,the melt fronts were smooth arcs,and there was no jetting or filling hysteresis occurred in the filling process.As shown in Fig.7,solid lines shows the regionFig.4.The equipments of visualization experiment.Fig.2.Photo of cavity plate.Table 3Experimental data and corresponding number.Inj.P (MPa)Inj.V (mm/s)408012010(1)(4)(7)30(2)(5)(8)50(3)(6)(9)Fig.3.Schematic of the visual mold.Design 53(2014)366–372can be directly observed,the wave front curve was derived directly from tracing the video capture,the contour shown in dashed line was inferred according to the flow pattern of the preceding para-graph.Through comparing between three schematic diagrams,it can be found that under the same processing parameters,a larger gate may cause a higher filling speed and there was hardly any short shot parts generated with gate M and gate L when the nozzle temperature was 190°C.The reason is that the volume flow rate of a large gate is generally higher than a small gate when the molding process is conducted in the same condition.As shown in Fig.8,through comparing the filling processes under different conditions,it can be concluded that the larger set of injection speed resulted in the faster filling rate.And there was no obvious relationship be-tween filling rate with injection pressure (Fig.9).On the whole,undersized gate like gate S will cause jetting and low filling speed.If molding process is conducted in condition of low injection rate or high injection pressure,the defect of shortshot will be able to generate.Therefore,for the filling behavior,undersized gate is disadvantageous.3.2.Residual stressThe residual stress in the specimens was examined by Stress Viewer R5.1(by Moldex3D,Fig.10),which is an instrument that could non-destructively and qualitatively observe the internal stress of transparent plastic parts.The instrument works by Brew-ster’s law of photo-elasticity.It uses the photo-elastic properties of plastic under stress to observe the variations of material birefrin-gence.When placing a transparent plastic sample between two polarized sheets and shining polarized light on it,the components of the light wave that are parallel and perpendicular to the direc-tion of the stress will propagate through the plastic with different speeds.Color fringes can be observed correspond to different speeds at that point,which in turn correspond to stress level,theFig.7.Filling process with three gates in the case of parameters (5).Fig.5.Filling process with gate S in the case of parameter (5).Fig.6.Specimens shaped by gate S with different nozzle temperature and injection pressure.principle is shown in Fig.11.From the color fringes patterns,the areas with higher density of color fringe lines higher stress inside can be learned.For a polymer material which has been subjected to stress and generated stress deformation,its refractive index of the light in the space will have a directional difference,in another words,the stress components of the plastic material in each directions are dif-ferent.As a result,the refractive index in these directions will also be different,and the difference will be proportional to the the for-mer.Therefore,by observing the light and dark fringes that were presented due to the different refractive index,the distribution and magnitude of residual stress can be known directly.With theoretic analysis and visualization techniques,Du et al.[24]once took rectangular plate cavity for the study,and observed the dynamic evolution process of residual stress during melt filling.They concluded that the residual stress near the point gate was sig-nificantly more than the fan gate.With the reduction of melt tem-perature or the increase of the holding pressure,the residual stress became larger.In this paper,the effects of various gate size andFig.10.Residual stress Viewer.Fig.11.Schematic diagram of birefringence.12.Residual stress distributions of specimens for three gates when injection rate was 30mm/s.9.Melt-flow-length of gate M with the injection speed of 30mms.(T-time,melt flow length)Melt-flow-length of gate M with the injection pressure of 40MPa.(T-time,flow length)parameters(including temperature,injection speed and injection pressure)on the residual stress were studied,and the discussion of the experimental results were as follows.As shown in Fig.12,when the injection rate was30mm/s and the nozzle temperature was190°C,the residual stress of speci-mens for three gates were significantly different.For ease of com-parison,the stress region had been divided into four parts according to the shape of the specimen.Stress of specimens shaped with gate S distributed much wider than specimens of the other two gates,the stress concentrations in the region of part2and part 3were particularly pared to gate S,residual stress of specimens shaped with gate M and L was much less than the for-mer.Difference between gate M and gate L was not obvious,but residual orientation,namely frozen in orientation[25,26].The chains with frozen orientation always have a development trend from high energy state to lower energy state,it means they may tend to curl,wound,or recrystallization,this will lead to inconsis-tent alignment direction and further generate internal stresses[26]. Therefore,when the meltflow rate is slower,the cooling rate will be faster,then the frozen in orientation will be more serious,thus the residual stress of products will be larger.That is why articles of gate S have the maximum residual stress and L has the minimum.Another set of contrasting results further demonstrate the influ-ence of temperature on the residual stress.As shown in Fig.14,in the case of injection rate of10mm/s,injection pressure of 120MPa,different nozzle temperature caused different residualFig.14.Residual stress distributions of specimens for gate S under different nozzle temperature.Fig.15.Residual stress distributions of specimens molded by gate M.Fig.13.Fig.13.Sketch of chains of a polymeric in different state[27]P.Xie et al./Materials and Design53(2014)366–372371the wall and in the center is larger than when the temperature was low,the cooling rate is uneven,made the difference of segment ori-entation became greater and thus the phenomenon occurred.In general,the residual stress will decline as the temperature rising, which is consistent with the conclusion of Du[24].In addition to the effect of gate size on residual stress,which also can be seen from Fig.12is that injection pressure has no sig-nificantly influence on the residual stress in this experiment.Fig.15shows the residual stress distribution of specimens molded by gate M.It can be found that the injection rate has a great influence on the residual stress.When the rate was10mm/ s,the residual stress distribution was the biggest and the difference with each other mainly lied in part1.The smallest stress was gen-erated in the case of50mm/s.This result suggests that a large speed is helpful to reducing the residual stress.Reason is that most of the polymer molecular chains are arranged along theflow direc-tion in thefilling process.Due to the faster injection rate resulted in the higher shear rate of the melt,it will lead to the higher orien-tation degree of the segment.Therefore,the preference consistency of products segment will be higher,while theflow residual stress will be small.From another point of view,due to the high injection rate,the temperature of melt in the cavity is relatively uniformly and high,according to the previous conclusions,it can be known that the thermal residual stress will also be small.Therefore,the total residual stress will be lower when the injection rate is higher.4.ConclusionsAccording to the results of injection molding visualization experiments and observations on residual stress,the following conclusions could be drawn.(1)Gate size is an important factor affecting thefilling behavior.The undersized gate will cause jetting and lowfilling speed, and is likely to produce short shot products.If the gate is appropriately enlarged,thefilling speed,flow stability and integrity of products will all be improved.Moreover,these effects are coupled with processing conditions,altering the injection speed and nozzle temperature will cause the change offilling behavior.(2)Gate can significantly impact the magnitude and distribu-tion of residual stress:A larger gate may generate smaller stress.Besides,the effect of injection speed and temperature on residual stress should not be ignored.The residual stress will be likely to reduce when the melt isfilling in a higher speed or a higher nozzle temperature.Through comparing between these three gates,it can be identi-fied in this paper that the undersized gate has many adverse effects on thefilling process and the residual stress.However,based on the traditional experience,the gate is not the larger the better.Fur-ther study is needed to be carried out in this aspect. AcknowledgementsThe authors are supported by the Laboratory of Advanced Poly-mer Processing.We gratefully acknowledge CoreTech System Co.,Ltd.(Moldex3D)and GSK CNC Equipment Co.,Ltd.for their gener-ous supply of the devices.Funding was provided by the National Natural Science Foundation of China(Grant Nos.51203009and 21174015).References[1]Pye RGW.Injection Mould Design.Harlow(Longman Scientific&Technical);1989.p.358.[2]Tor SB,Loh NH,Khor KA,Yoshida H.The effects of gate size in powder injectionmolding.Mater Manuf Processes1997;12(4):629–40.[3]Shen YK,Wu CW,Yuc YF,Chungc HW.Analysis for optimal gate design of thin-walled injection molding.Int Commun Heat Mass Trans2008;35(6):728–34.[4]Xie L,Ziegmann G.Effect of gate dimension on micro injection molded weldline strength with polypropylene(PP)and high-density polyethylene(HDPE).Int J Adv Manuf Technol2010;48(1–4):71–81.[5]Xie PC,Du B,Yan ZY,Ding YM,Yang WM.Visual experiment study on theinfluence of mold structure design on injection molding product’s defects.Adv Mater Res2010;87–88:31–5.[6]Yokoi H.Recent development of visualization analysis techniques in injectionmolding.Denso Tech Rev2006;11(2):3–13.[7]Yokoi H,Masuda N,Mitsuhata H.Visualization analysis offlow front behaviorduringfilling process of injection mold cavity by two-axis tracking system.J Mater Process Technol2002;130–131:328–33.[8]Ohta T,Yokoi H.Visual analysis of cavityfilling and packing process ininjection molding of thermoset phenolic resin by the gate-magnetization method.Polym Eng Sci2001;41(5):806–19.[9]Yokoi H.Visualization and measurement technologies for ultra-high-speedinjection molding phenomena.Prod Res2007;59:483–91.[10]Yoshimura Y,Endo M,Yokoi H.Visualization analysis of meltfilling behaviorfrom submarine-gate in ultra-high-speed injection molding.Prod Res 2009;61:985–8.[11]Liu SJ,Wu YC.Dynamic visualization of cavity-filling process influid-assistedinjection molding-gas versus water.Polym Test2007;26(2):232–42.[12]Mehdi M,Amir HB,Mohammad Rezavand SA,Amir P.Visualization of bubbledynamics in foam injection molding.J Appl Polym Sci2010;116(6):3346–55.[13]Demirer A,Soydan Y,Kapti AO.An experimental investigation of the effects ofhot runner system on injection moulding process in comparison with conventional runner system.Mater Des2007;28:1467–76.[14]Wang TH,Young WB.Study on residual stresses of thin-walled injectionmolding.Euro Polym J2005;41:2511–7.[15]Zoetelief WF,Douven LFA,Ingen Housz AJ.Residual thermal stresses ininjection molded products.Polym Eng Sci1996;36(14):1886–96.[16]Kamal MR,Lai-Fook RA,Hernandez-Aguilar JR.Residual thermal stresses ininjection moldings of thermoplastics:a theoretical and experimental study.Polym Eng Sci2002;42(5):1098–114.[17]Wimberger-Friedl R,de Bruin JG,Schoo HFM.Residual birefringence inmodified polycarbonates.Polym Eng Sci2003;43(1):62–70.[18]Fiske T,Gokturk HS,Yazici R,Kalyon DM.Effects offlow induced orientation offerromagnetic particles on relative magnetic permeability of injection molded composites.Polym Eng Sci1997;37(5):826.[19]Yamada K,Tomari K,Ishiaku US,Hamada H.Fracture toughness evaluation ofadjacentflow weld line in polystyrene by the SENB method.Polym Eng Sci 2005;45(8):1059–66.[20]Tumbull A,Maxwell AS,Pillai S.Residual stress in polymers evaluation ofmeasurement techniques.J Mater Sci1999;34(3):451–9.[21]Neves NM,Pouzada AS.The use of birefringence for predicting the stiffness ofinjection molded polycarbonate discs.Polym Eng Sci1998;38(10):1770–7. [22]Wimberger-Friedl R.The assessment of orientation,stress and densitydistributions in injection-molded amorphous polymers by optical techniques.Prog Polym Sci1995;20(3):369–99.[23]ISO527-2.Plastics—determination of tensile properties—Part2:Testconditions for moulding and extrusion plastics;2012.[24]Du B.Dynamic visualization experimental study of internal stress on theoptical products.Beijing University of Chemical Technology;2011.[25]Jansen KMB,Flaman AAM.The influence of surface heating on thebirefringence distribution in injection molded parts.Polym Eng Sci 1994;34(11):898–904.[26]Xu QJ,Yu SW.Calculation of residual stress in injection molded productionmolded products for polymer materials.Chinese J Theor Appl Mech 1998;30:157–67.[27]ten Grotenhuis SM,Piazolo S,Pakula T,Passchier CW,Bons PD.Are polymerssuitable rock analogs?Tectonophysics2002;350(1):35–47.372P.Xie et al./Materials and Design53(2014)366–372。
模具毕业设计外文翻译(英文+译文)
Injection MoldingThe basic concept of injection molding revolves around the ability of a thermoplastic material to be softened by heat and to harden when cooled .In most operations ,granular material (the plastic resin) is fed into one end of the cylinder (usually through a feeding device known as a hopper ),heated, and softened(plasticized or plasticized),forced out the other end of the cylinder, while it is still in the form of a melt, through a nozzle into a relatively cool mold held closed under pressure.Here,the melt cools and hardens until fully set-up. The mold is then opened, the piece ejected, and the sequence repeated.Thus, the significant elements of an injection molding machine become: 1) the way in which the melt is plasticized (softened) and forced into the mold (called the injection unit);2) the system for opening the mold and closing it under pressure (called the clamping unit);3) the type of mold used;4) the machine controls.The part of an injection-molding machine, which converts a plastic material from a sold phase to homogeneous seni-liguid phase by raising its temperature .This unit maintains the material at a present temperature and force it through the injection unit nozzle into a mold .The plunger is a combination of the injection and plasticizing device in which a heating chamber is mounted between the plunger and mold. This chamber heats the plastic material by conduction .The plunger, on each stroke; pushes unbelted plastic material into the chamber, which in turn forces plastic melt at the front of the chamber out through the nozzleThe part of an injection molding machine in which the mold is mounted, and which provides the motion and force to open and close the mold and to hold the mold close with force during injection .This unit can also provide other features necessary for the effective functioning of the molding operation .Movingplate is the member of the clamping unit, which is moved toward a stationary member. the moving section of the mold is bolted to this moving plate .This member usually includes the ejector holes and mold mounting pattern of blot holes or “T” slots .Stationary plate is the fixed member of the clamping unit on which the stationary section of the mold is bolted .This member usually includes a mold-mounting pattern of boles or “T” slots. Tie rods are member of the clamping force actuating mechanism that serve as the tension member of the clamp when it is holding the mold closed. They also serve as a gutted member for the movable plate .Ejector is a provision in the clamping unit that actuates a mechanism within the mold to eject the molded part(s) from the mold .The ejection actuating force may be applied hydraulically or pneumatically by a cylinder(s) attached to the moving plate, or mechanically by the opening stroke of the moving plate.Methods of melting and injecting the plastic differ from one machine to another and are constantly being implored .conventional machines use a cylinder and piston to do both jobs .This method simplifies machine construction but makes control of injection temperatures and pressures an inherently difficult problem .Other machines use a plasticizing extruder to melt the plastic and piston to inject it while some hare been designed to use a screw for both jobs :Nowadays, sixty percent of the machines use a reciprocating screw,35% a plunger (concentrated in the smaller machine size),and 5%a screw pot.Many of the problems connected with in ejection molding arise because the densities of polymers change so markedly with temperature and pressure. thigh temperatures, the density of a polymer is considerably cower than at room temperature, provided the pressure is the same.Therefore,if molds were filled at atmospheric pressure, “shrinkage” would make the molding deviate form the shape of the mold.To compensate for this poor effect, molds are filled at high pressure. The pressure compresses the polymer and allows more materials to flow into the mold, shrinkage is reduced and better quality moldings are produced.Cludes a mold-mounting pattern of bolt holes or “T” slots. Tie rods are members of the clamping force actuating mechanism that serve as the tension members of clamp when it is holding the mold closed. Ejector is a provision in the calming unit that actuates a mechanism within the mold to eject the molded part(s) form the mold. The ejection actuating force may be applied hydraulically or pneumatically by a cylinder(s) attached to the moving plate, or mechanically by the opening stroke of the moving plate.The function of a mold is twofold: imparting the desired shape to the plasticized polymer and cooling the injection molded part. It is basically made up of two sets of components: the cavities and cores and the base in which the cavities and cores are mounted. The mold ,which contains one or more cavities, consists of two basic parts :(1) a stationary molds half one the side where the plastic is injected,(2)Moving half on the closing or ejector side of the machine. The separation between the two mold halves is called the parting line. In some cases the cavity is partly in the stationary and partly in the moving section. The size and weight of the molded parts limit the number of cavities in the mold and also determine the machinery capacity required. The mold components and their functions are as following:(1)Mold Base-Hold cavity (cavities) in fixed, correctposition relative to machine nozzle.(2)Guide Pins-Maintain Proper alignment of entry into moldinterior.(3)Spree Bushing (spree)-Provide means of entry into moldinterior.(4)Runners-Conroy molten plastic from spree to cavities.(5)Gates-Control flow into cavities.(6)Cavity (female) and Force (male)-Control the size,shape and surface of mold article.(7)Water Channels-Control the temperature of mold surfacesto chill plastic to rigid state.(8)Side (actuated by came, gears or hydrauliccylinders)-Form side holes, slots, undercuts and threaded sections.(9)Vent-Allow the escape of trapped air and gas.(10)Ejector Mechanism (pins, blades, stripper plate)-Ejectrigid molded article form cavity or force.(11)Ejector Return Pins-Return ejector pins to retractedposition as mold closes for next cycle.The distance between the outer cavities and the primary spree must not be so long that the molten plastic loses too much heat in the runner to fill the outer cavities properly. The cavities should be so arranged around the primary spree that each receives its full and equal share of the total pressure available, through its own runner system (or the so-called balanced runner system).The requires the shortest possible distance between cavities and primary sprue, equal runner and gate dimension, and uniform culling.注射成型注射成型的基本概念是使热塑性材料在受热时熔融，冷却时硬化，在大部分加工中，粒状材料（即塑料树脂）从料筒的一端（通常通过一个叫做“料斗”的进料装置）送进，受热并熔融（即塑化或增塑），然后当材料还是溶体时，通过一个喷嘴从料筒的另一端挤到一个相对较冷的压和封闭的模子里。
注塑模具毕业设计外文翻译--立体光照成型的注塑模具工艺的综合模拟
附录2Integrated simulation of the injection molding process withstereolithography moldsAbstract Functional parts are needed for design verification testing, field trials, customer evaluation, and production planning. By eliminating multiple steps, the creation of the injection mold directly by a rapid prototyping (RP) process holds the best promise of reducing the time and cost needed to mold low-volume quantities of parts. The potential of this integration of injection molding with RP has been demonstrated many times. What is missing is the fundamental understanding of how the modifications to the mold material and RP manufacturing process impact both the mold design and the injection molding process. In addition, numerical simulation techniques have now become helpful tools of mold designers and process engineers for traditional injection molding. But all current simulation packages for conventional injection molding are no longer applicable to this new type of injection molds, mainly because the property of the mold material changes greatly. In this paper, an integrated approach to accomplish a numerical simulation of injection molding into rapid-prototyped molds is established and a corresponding simulation system is developed. Comparisons with experimental results are employed for verification, which show that the present scheme is well suited to handle RP fabricated stereolithography (SL) molds.Keywords Injection molding Numerical simulation Rapid prototyping1 IntroductionIn injection molding, the polymer melt at high temperature is injected into the mold under high pressure [1]. Thus, the mold material needs to have thermal and mechanical properties capable of withstanding the temperatures and pressures of the molding cycle. The focus of many studies has been to create theinjection mold directly by a rapid prototyping (RP) process. By eliminating multiple steps, this method of tooling holds the best promise of reducing the time and cost needed to create low-volume quantities of parts in a production material. The potential of integrating injection molding with RP technologies has been demonstrated many times. The properties of RP molds are very different from those of traditional metal molds. The key differences are the properties of thermal conductivity and elastic modulus (rigidity). For example, the polymers used in RP-fabricated stereolithography (SL) molds have a thermal conductivity that is less than onethousandth that of an aluminum tool. In using RP technologies to create molds, the entire mold design and injection-molding process parameters need to be modified and optimized from traditional methodologies due to the completely different tool material. However, there is still not a fundamen tal understanding of how the modifications t o the mold tooling method and material impact both the mold design and the injection molding process parameters. One cannot obtain reasonable results by simply changing a few material properties in current models. Also, using traditional approaches when making actual parts may be generating sub-optimal results. So there is a dire need to study the interaction between the rapid tooling (RT) process and material and injection molding, so as to establish the mold design criteria and techniques for an RT-oriented injection molding process.In addition, computer simulation is an effective approach for predicting the quality of molded parts. Commercially available simulation packages of the traditional injection molding process have now become routine tools of the mold designer and process engineer [2]. Unfortunately, current simulation programs for conventional injection molding are no longer applicable to RP molds, because of the dramatically dissimilar tool material. For instance, in using the existing simulation software with aluminum and SL molds and comparing with experimental results, though the simulation values of part distortion are reasonable for the aluminum mold, results are unacceptable, with the error exceeding 50%. The distortion during injection molding is due to shrinkage and warpage of the plastic part, as well as the mold. For ordinarily molds, the main factor is the shrinkage and warpage of the plastic part, which is modeled accurately in current simulations. But for RP molds, the distortion of the mold has potentially more influence, which have been neglected in current models. For instance, [3] used a simple three-step simulation process to consider the mold distortion, which had too much deviation.In this paper, based on the above analysis, a new simulation system for RP molds is developed. The proposed system focuses on predicting part distortion, which is dominating defect in RP-molded parts. The developed simulation can be applied as an evaluation tool for RP mold design and process optimization. Our simula tion system is verified by an experimental example.Although many materials are available for use in RP technologies, we concentrate on using stereolithography (SL), the original RP technology, to create polymer molds. The SL process uses photopolymer and laser energy to build a part layer by layer. Using SL takes advantage of both the commercial dominance of SL in the RP industry and the subsequent expertise base that has been developed for creating accurate, high-quality parts. Until recently, SL was primarily used to create physical models for visual inspection and form-fit studies with very limited func-tional applications. However, the newer generation stereolithographic photopolymers have improved dimensional, mechanical and thermal properties making it possible to use them for actual functional molds.2 Integrated simulation of the molding process2.1 MethodologyIn order to simulate the use of an SL mold in the injection molding process, an iterative method is proposed. Different software modules have been developed and used to accomplish this task. The main assumption is that temperature and load boundary conditions cause significant distortions in the SL mold. The simulation steps are as follows:1The part geometry is modeled as a solid model, which is translated to a file readable by the flow analysis package.2Simulate the mold-filling process of the melt into a pho topolymer mold, which will output the resulting temperature and pressure profiles.3Structural analysis is then performed on the photopolymer mold model using the thermal and load boundary conditions obtained from the previous step, which calculates the distortion that the mold undergo during the injection process.4If the distortion of the mold converges, move to the next step. Otherwise, the distorted mold cavity is then modeled (changes in the dimensions of the cavity after distortion), and returns to the second step to simulate the melt injection into the distorted mold.5The shrinkage and warpage simulation of the injection molded part is then applied, which calculates the final distor tions of the molded part.In above simulation flow, there are three basic simulation mod ules.2. 2 Filling simulation of the melt2.2.1 Mathematical modelingIn order to simulate the use of an SL mold in the injection molding process, an iterative method is proposed. Different software modules have been developed and used to accomplish this task. The main assumption is that temperature and load boundary conditions cause significant distortions in the SL mold. The simulation steps are as follows:1. The part geometry is modeled as a solid model, which is translated to a file readable by the flow analysis package.2. Simulate the mold-filling process of the melt into a photopolymer mold, which will output the resulting temperature and pressure profiles.3. Structural analysis is then performed on the photopolymer mold model using the thermal and load boundary conditions obtained from the previous step, which calculates the distortion that the mold undergo during the injection process.4. If the distortion of the mold converges, move to the next step. Otherwise, the distorted mold cavity is then modeled (changes in the dimensions of the cavity after distortion), and returns to the second step to simulate the melt injection into the distorted mold.5. The shrinkage and warpage simulation of the injection molded part is then applied, which calculates the final distortions of the molded part.In above simulation flow, there are three basic simulation modules.2.2 Filling simulation of the melt2.2.1 Mathematical modelingComputer simulation techniques have had success in predicting filling behavior in extremely complicated geometries. However, most of the current numerical implementation is based on a hybrid finite-element/finite-difference solution with the middleplane model. The application process of simulation packages based on this model is illustrated in Fig. 2-1. However, unlike the surface/solid model in mold-design CAD systems, the so-called middle-plane (as shown in Fig. 2-1b) is an imaginary arbitrary planar geometry at the middle of the cavity in the gap-wise direction, which should bring about great inconvenience in applications. For example, surface models are commonly used in current RP systems (generally STL file format), so secondary modeling is unavoidable when using simulation packages because the models in the RP and simulation systems are different. Considering these defects, the surface model of the cavity is introduced as datum planes in the simulation, instead of the middle-plane.According to the previous investigations [4–6], fillinggoverning equations for the flow and temperature field can be written as:where x, y are the planar coordinates in the middle-plane, and z is the gap-wise coordinate; u, v,w are the velocity components in the x, y, z directions; u, v are the average whole-gap thicknesses; and η, ρ,CP (T), K(T) represent viscosity, density, specific heat and thermal conductivity of polymer melt, respectively.Fig.2-1 a–d. Schematic procedure of the simulation with middle-plane model. a The 3-D surface model b The middle-plane model c The meshed middle-plane model d The display of the simulation result In addition, boundary conditions in the gap-wise direction can be defined as:where TW is the constant wall temperature (shown in Fig. 2a).Combining Eqs. 1–4 with Eqs. 5–6, it follows that the distributions of the u, v, T, P at z coordinates should be symmetrical, with the mirror axis being z = 0, and consequently the u, v averaged in half-gap thickness is equal to that averaged in wholegap thickness. Based on this characteristic, we can divide the whole cavity into two equal parts in the gap-wise direction, as described by Part I and Part II in Fig. 2b. At the same time, triangular finite elements are generated in the surface(s) of the cavity (at z = 0 in Fig. 2b), instead of the middle-plane (at z = 0 in Fig. 2a). Accordingly, finite-difference increments in the gapwise direction are employed only in the inside of the surface(s) (wall to middle/center-line), which, in Fig. 2b, means from z = 0 to z = b. This is single-sided instead of two-sided with respect to the middle-plane (i.e. from the middle-line to two walls). In addition, the coordinate system is changed from Fig. 2a to Fig. 2b to alter the finite-element/finite-difference scheme, as shown in Fig. 2b. With the above adjustment, governing equations are still Eqs. 1–4. However, the original boundary conditions inthe gapwise direction are rewritten as:Meanwhile, additional boundary conditions must be employed at z = b in order to keep the flows at the juncture of the two parts at the same section coordinate [7]:where subscripts I, II represent the parameters of Part I and Part II, respectively, and Cm-I and Cm-II indicate the moving free melt-fronts of the surfaces of the divided two parts in the filling stage.It should be noted that, unlike conditions Eqs. 7 and 8, ensuring conditions Eqs. 9 and 10 are upheld in numerical implementations becomes more difficult due to the following reasons:1. The surfaces at the same section have been meshed respectively, which leads to a distinctive pattern of finite elements at the same section. Thus, an interpolation operation should be employed for u, v, T, P during the comparison between the two parts at the juncture.2. Because the two parts have respective flow fields with respect to the nodes at point A and point C (as shown in Fig. 2b) at the same section, it is possible to have either both filled or one filled (and one empty). These two cases should be handled separately, averaging the operation for the former, whereas assigning operation for the latter.3. It follows that a small difference between the melt-fronts is permissible. That allowance can be implemented by time allowance control or preferable location allowance control of the melt-front nodes.4. The boundaries of the flow field expand by each melt-front advancement, so it is necessary to check the condition Eq. 10 after each change in the melt-front.5. In view of above-mentioned analysis, the physical parameters at the nodes of the same section should be compared and adjusted, so the information describing finite elements of the same section should be prepared before simulation, that is, the matching operation among the elements should be preformed.Fig. 2a,b. Illustrative of boundary conditions in the gap-wise direction a of the middle-plane model b of thesurface model2.2.2 Numerical implementationPressure field. In modeling viscosity η, which is a function of shear rate, temperature and pressure of melt, the shear-thinning behavior can be well represented by a cross-type model such as:where n corresponds to the power-law index, and τ∗ characterizes the shear stress level of the transition region between the Newtonian and power-law asymptotic limits. In terms of an Arrhenius-type temperature sensitivity and exponential pressure dependence, η0(T, P) can be represented with reasonable accuracy as follows:Equations 11 and 12 constitute a five-constant (n, τ∗, B, Tb, β) representation for viscosity. The shear rate for viscosity calculation is obtained by:Based on the above, we can infer the following filling pressure equation from the governing Eqs. 1–4:where S is calculated by S = b0/(b−z)2η d z. Applying the Galerkin method, the pressure finite-element equation is deduced as:where l_ traverses all elements, including node N, and where I and j represent the local node number in element l_ corresponding to the node number N and N_ in the whole, respectively. The D(l_) ij is calculated as follows:where A(l_) represents triangular finite elements, and L(l_) i is the pressure trial function in finite elements.Temperature field. To determine the temperature profile across the gap, each triangular finite element at the surface is further divided into NZ layers for the finite-difference grid.The left item of the energy equation (Eq. 4) can be expressed as:where TN, j,t represents the temperature of the j layer of node N at time t.The heat conduction item is calculated by:where l traverses all elements, including node N, and i and j represent the local node number in element l corresponding to the node number N and N_ in the whole, respectively.The heat convection item is calculated by:For viscous heat, it follows that:Substituting Eqs. 17–20 into the energy equation (Eq. 4), the temperature equation becomes:2.3 Structural analysis of the moldThe purpose of structural analysis is to predict the deformation occurring in the photopolymer mold due to the thermal and mechanical loads of the filling process. This model is based on a three-dimensional thermoelastic boundary element method (BEM). The BEM is ideally suited for this application because only the deformation of the mold surfaces is of interest. Moreover, the BEM has an advantage over other techniques in that computing effort is not wasted on calculating deformation within the mold.The stresses resulting from the process loads are well within the elastic range of the mold material. Therefore, the mold deformation model is based on a thermoelastic formulation. The thermal and mechanical properties of the mold are assumed to be isotropic and temperature independent.Although the process is cyclic, time-averaged values of temperature and heat flux are used for calculating the mold deformation. Typically, transient temperature variations within a mold have been restricted to regions local to the cavity surface and the nozzle tip [8]. The transients decay sharply with distance from the cavity surface and generally little variation is observed beyond distances as small as 2.5 mm. This suggests that the contribution from the transients to the deformation at the mold block interface is small, and therefore it is reasonable to neglect the transient effects. The steady state temperature field satisfies Laplace’s equation 2T = 0 and the time-averaged boundary conditions. The boundary conditions on the mold surfaces are described in detail by Tang et al. [9]. As for the mechanical boundary conditions, the cavity surface is subjected to the melt pressure, the surfaces of the mold connected to the worktable are fixed in space, and other external surfaces are assumed to be stress free.The derivation of the thermoelastic boundary integral formulation is well known [10]. It is given by:where uk, pk and T are the displacement, traction and temperature,α, ν represent the thermal expansion coefficient and Poisson’s ratio of the material, and r = |y−x|. clk(x) is the surfacecoefficient which depends on the local geometry at x, the orientation of the coordinate frame and Poisson’s ratio for the domain [11]. The fundamental displacement ˜ulk at a point y in the xk direction, in a three-dimensional infinite isotropic elastic domain, results from a unit load concentrated at a point x acting in the xl direction and is of the form:where δlk is the Kronecker delta function and μ is the shear modulus of the mold material.The fundamental traction ˜plk , measured at the point y on a surface with unit normal n, is:Discretizing the surface of the mold into a total of N elements transforms Eq. 22 to:where Γn refers to the n th surface element on the domain.Substituting the appropriate linear shape functions into Eq. 25, the linear boundary element formulation for the mold deformation model is obtained. The equation is applied at each node on the discretized mold surface, thus giving a system of 3N linear equations, where N is the total number of nodes. Each node has eight associated quantities: three components of displacement, three components of traction, a temperature and a heat flux. The steady state thermal model supplies temperature and flux values as known quantities for each node, and of the remaining six quantities, three must be specified. Moreover, the displacement values specified at a certain number of nodes must eliminate the possibility of a rigid-body motion or rigid-body rotation to ensure a non-singular system of equations. The resulting system of equations is assembled into a integrated matrix, which is solved with an iterative solver.2.4 Shrinkage and warpage simulation of the molded partInternal stresses in injection-molded components are the principal cause of shrinkage and warpage. These residual stresses are mainly frozen-in thermal stresses due to inhomogeneous cooling, when surface layers stiffen sooner than the core region, as in free quenching. Based onthe assumption of the linear thermo-elastic and linear thermo-viscoelastic compressible behavior of the polymeric materials, shrinkage and warpage are obtained implicitly using displacement formulations, and the governing equations can be solved numerically using a finite element method.With the basic assumptions of injection molding [12], the components of stress and strain are given by:The deviatoric components of stress and strain, respectively, are given byUsing a similar approach developed by Lee and Rogers [13] for predicting the residual stresses in the tempering of glass, an integral form of the viscoelastic constitutive relationships is used, and the in-plane stresses can be related to the strains by the following equation:Where G1 is the relaxation shear modulus of the material. The dilatational stresses can be related to the strain as follows:Where K is the relaxation bulk modulus of the material, and the definition of α and Θ is: If α(t) = α0, applying Eq. 27 to Eq. 29 results in:Similarly, applying Eq. 31 to Eq. 28 and eliminating strain εxx(z, t) results in:Employing a Laplace transform to Eq. 32, the auxiliary modulus R(ξ) is given by:Using the above constitutive equation (Eq. 33) and simplified forms of the stresses and strains in the mold, the formulation of the residual stress of the injection molded part during the cooling stage is obtain by:Equation 34 can be solved through the application of trapezoidal quadrature. Due to the rapid initial change in the material time, a quasi-numerical procedure is employed for evaluating the integral item. The auxiliary modulus is evaluated numerically by the trapezoidal rule.For warpage analysis, nodal displacements and curvatures for shell elements are expressed as:where [k] is the element stiffness matrix, [Be] is the derivative operator matrix, {d} is the displacements, and {re} is the element load vector which can be evaluated by:The use of a full three-dimensional FEM analysis can achieve accurate warpage results, however, it is cumbersome when the shape of the part is very complicated. In this paper, a twodimensional FEM method, based on shell theory, was used because most injection-molded parts have a sheet-like geometry in which the thickness is much smaller than the other dimensions of the part. Therefore, the part can be regarded as an assembly of flat elements to predict warpage. Each three-node shell element is a combination of a constant strain triangular element (CST) and a discrete Kirchhoff triangular element (DKT), as shown in Fig. 3. Thus, the warpage can be separated into plane-stretching deformation of the CST and plate-bending deformation of the DKT, and correspondingly, the element stiffness matrix to describe warpage can also be divided into the stretching-stiffness matrix and bending-stiffness matrix.Fig. 3a–c. Deformation decomposition of shell element in the local coordinate system. a In-plane stretchingelement b Plate-bending element c Shell element3 Experimental validationTo assess the usefulness of the proposed model and developed program, verification is important. The distortions obtained from the simulation model are compared to the ones from SL injection molding experiments whose data is presented in the literature [8]. A common injection molded part with the dimensions of 36×36×6 mm is considered in the experiment, as shown in Fig. 4. The thickness dimensions of the thin walls and rib are both 1.5 mm; and polypropylene was used as the injection material. The injection machine was a production level ARGURY Hydronica 320-210-750 with the following process parameters: a melt temperature of 250 ◦C; an ambient temperature of 30 ◦C; an injection pressure of 13.79 MPa; an injection time of 3 s; and a cooling time of 48 s. The SL material used, Dupont SOMOSTM 6110 resin, has the ability to resist temperatures of up to 300 ◦C temperatures. As mentioned above, thermal conductivity of the mold is a major factor that differentiates between an SL and a traditional mold. Poor heat transfer in the mold would produce a non-uniform temperature distribution, thus causing warpage that distorts the completed parts. For an SL mold, a longer cycle time would be expected. The method of using a thin shell SL mold backed with a higher thermal conductivity metal (aluminum) was selected to increase thermal conductivity of the SL mold.Fig. 4. Experimental cavity modelFig. 5. A comparison of the distortion variation in the X direction for different thermal conductivity; where “Experimental”, “present”, “three-step”, and “conventional” mean the results of the experimental, the presented simulation, the three-step simulation process and the conventional injection molding simulation, respectively.Fig. 6. Comparison of the distortion variation in the Y direction for different thermal conductivitiesFig. 7. Comparison of the distortion variation in the Z direction for different thermal conductivitiesFig. 8. Comparison of the twist variation for different thermal conductivities For this part, distortion includes the displacements in three directions and the twist (the difference in angle between two initially parallel edges). The validation results are shown in Fig.5 to Fig. 8. These figures also include the distortion values predicted by conventional injection molding simulation and the three-step model reported in [3].4 ConclusionsIn this paper, an integrated model to accomplish the numerical simulation of injection molding into rapid-prototyped molds is established and a corresponding simulation system is developed. For verification, an experiment is also carried out with an RPfabricated SL mold.It is seen that a conventional simulation using current injection molding software breaks down for a photopolymer mold. It is assumed that this is due to the distortion in the mold caused by the temperature and load conditions of injection. The three-step approach also has much deviation. The developed model gives results closer to experimental.Improvement in thermal conductivity of the photopolymer significantly increases part quality. Since the effect of temperature seems to be more dominant than that of pressure (load), an improvement in the thermal conductivity of the photopolymer can improve the part quality significantly.Rapid Prototyping (RP) is a technology makes it possible to manufacture prototypes quickly and inexpensively, regardless of their complexity. Rapid Tooling (RT) is the next step in RP’s steady progress and much work is being done to obtain more accurate tools to define the parameters of the process. Existing simulation tools can not provide the researcher with a useful means of studying relative changes. An integrated model, such as the one presented in this paper, is necessary to obtain accurate predictions of the actual quality of final parts. In the future, we expect to see this work expanded to develop simulations program for injection into RP molds manufactured by other RT processes.References1. Wang KK (1980) System approach to injection molding process. Polym-Plast Technol Eng 14(1):75–93.2. Shelesh-Nezhad K, Siores E (1997) Intelligent system for plastic injection molding process design. J Mater Process Technol 63(1–3):458–462.3. Aluru R, Keefe M, Advani S (2001) Simulation of injection molding into rapid-prototyped molds. Rapid Prototyping J 7(1):42–51.4. Shen SF (1984) Simulation of polymeric flows in the injection molding process. Int J Numer Methods Fluids 4(2):171–184.5. Agassant JF, Alles H, Philipon S, Vincent M (1988) Experimental and theoretical study of the injection molding of thermoplastic materials. Polym Eng Sci 28(7):460–468.6. Chiang HH, Hieber CA, Wang KK (1991) A unified simulation of the filling and post-filling stages in injection molding. Part I: formulation. Polym Eng Sci 31(2):116–124.7. Zhou H, Li D (2001) A numerical simulation of the filling stage in injection molding based on a surface model. Adv Polym Technol 20(2):125–131.8. Himasekhar K, Lottey J, Wang KK (1992) CAE of mold cooling in injection molding using a three-dimensional numerical simulation. J EngInd Trans ASME 114(2):213–221.9. Tang LQ, Pochiraju K, Chassapis C, Manoochehri S (1998) Computeraided optimization approach for the design of injection mold cooling systems. J Mech Des, Trans ASME 120(2):165–174.10. Rizzo FJ, Shippy DJ (1977) An advanced boundary integral equation method for three-dimensional thermoelasticity. Int J Numer Methods Eng 11:1753–1768.11. Hartmann F (1980) Computing the C-matrix in non-smooth boundary points. In: New developments in boundary element methods, CML Publications, Southampton, pp 367–379.12. Chen X, Lama YC, Li DQ (2000) Analysis of thermal residual stress in plastic injection molding. J Mater Process Technol 101(1):275–280.13. Lee EH, Rogers TG (1960) Solution of viscoelastic stress analysis problems using measured creep or relaxation function. J Appl Mech 30(1):127–134.14. Li Y (1997) Studies in direct tooling using stereolithography. Dissertation, University of Delaware, Newark, DE..。
模具毕业设计英译汉（Injection_molding）
模具毕业设计英译汉（Injection_molding）Injection moldingInjection molding (British English: moulding) is a manufacturing process for producing parts from both thermoplastic and thermosetting plastic materials. Material is fed into a heated barrel, mixed, and forced into a mold cavity where it cools and hardens to the configuration of the mold cavity.After a product is designed, usually by an industrial designer or an engineer, molds are made by a moldmaker (or toolmaker) from metal, usually either steel or aluminum, and precision-machined to form the features of the desired part. Injection molding is widely used for manufacturing a variety of parts, from the smallest component to entire body panels of cars.ApplicationsInjection molding is used to create many things such as wire spools, packaging, bottle caps, automotive dashboards, pocket combs, and most other plastic products available today. Injection molding is the most common method of part manufacturing. It is ideal for producing high volumes of the same object.Some advantages of injection molding are high production rates, repeatable high tolerances, the ability to use a wide range of materials, low labor cost, minimal scrap losses, and little need to finish parts after molding. Some disadvantages of this process are expensive equipment investment, potentially high running costs, and the need to design moldable parts.EquipmentPaper clip mold opened in molding machine; the nozzle is visible at rightMain article: Injection molding machineInjection molding machines consist of a material hopper, an injection ram or screw-type plunger, and a heating unit. They are also known as presses, they hold the molds in which the components are shaped. Presses are rated by tonnage, which expresses the amount of clamping force that the machine can exert. This force keeps the mold closed during the injection process. Tonnage can vary from less than 5 tons to 6000 tons, with the higher figures used in comparatively few manufacturing operations. The total clamp force needed is determined by the projected area of the part being molded. This projected area is multiplied by a clamp force of from 2 to 8 tons for each square inch of the projected areas. As a rule of thumb, 4 or 5 tons/in2 can be used for most products. If the plastic material is very stiff, it will require more injection pressure to fill the mold, thus more clamp tonnage to hold the mold closed. The required force can also be determined by the material used and the size of the part, larger parts require higher clamping force.MoldMold or die are the common terms used to describe the tooling used to produce plastic parts in molding.Since molds have been expensive to manufacture, they were usually only used in mass production where thousands of parts were being produced. Typical molds are constructed from hardened steel, pre-hardened steel, aluminum, and/or beryllium-copper alloy. The choice of material to build a mold from is primarily one of economics; in general, steel molds cost more to construct, but their longer lifespan will offset the higher initial cost over a higher number of parts made before wearing out. Pre-hardened steel molds are less wear-resistant and are used for lower volume requirements or larger components. The typicalsteel hardness is 38-45 on the Rockwell-C scale. Hardened steel molds are heat treated after machining. These are by far the superior in terms of wear resistance and lifespan. Typical hardness ranges between 50 and 60 Rockwell-C (HRC). Aluminum molds can cost substantially less, and, when designed and machined with modern computerized equipment, can be economical for molding tens or even hundreds of thousands of parts. Beryllium copper is used in areas of the mold that require fast heat removal or areas that see the most shear heat generated. The molds can be manufactured either by CNC machining or by using Electrical Discharge Machining processes.Mold DesignStandard two plates tooling –core and cavity are inserts in a mold base – "Family mold" of 5 different partsThe mold consists of two primary components, the injection mold (A plate) and the ejector mold (B plate). Plastic resin enters the mold through a sprue in the injection mold, the sprue bushing is to seal tightly against the nozzle of the injection barrel of the molding machine and to allow molten plastic to flow from the barrel into the mold, also known as cavity The sprue bushing directs the molten plastic to the cavity images through channels that are machined into the faces of the A and B plates. These channels allow plastic to run along them, so they are referred to as runners.The molten plastic flows through the runner and enters one or more specialized gates and into the cavity geometry to form the desired part.The amount of resin required to fill the sprue, runner and cavities of a mold is a shot. Trapped air in the mold can escape through air vents that are ground into the parting line of the mold. If the trapped air is not allowed to escape, it is compressedby the pressure of the incoming material and is squeezed into the corners of the cavity, where it prevents filling and causes other defects as well. The air can become so compressed that it ignites and burns the surrounding plastic material. To allow for removal of the molded part from the mold, the mold features must not overhang one another in the direction that the mold opens, unless parts of the mold are designed to move from between such overhangs when the mold opens (utilizing components called Lifters).Sides of the part that appear parallel with the direction of draw (The axis of the cored position (hole) or insert is parallel to the up and down movement of the mold as it opens and closes)are typically angled slightly with (draft) to ease release of the part from the mold. Insufficient draft can cause deformation or damage. The draft required for mold release is primarily dependent on the depth of the cavity: the deeper the cavity, the more draft necessary. Shrinkage must also be taken into account when determining the draft required.If the skin is too thin, then the molded part will tend to shrink onto the cores that form them while cooling, and cling to those cores or part may warp, twist, blister or crack when the cavity is pulled away. The mold is usually designed so that the moldedpart reliably remains on the ejector (B) side of the mold when it opens, and draws the runner and the sprue out of the (A) side along with the parts. The part then falls freely when ejected from the (B) side. Tunnel gates, also known as submarine or mold gate, is located below the parting line or mold surface. The opening is machined into the surface of the mold on the parting line. The molded part is cut (by the mold) from the runner system on ejection from the mold. Ejector pins, also known as knockout pin,is a circular pin placed in either half of the mold (usually the ejector half), which pushes the finished molded product, or runner system out of a mold.The standard method of cooling is passing a coolant (usually water) through a series of holes drilled through the mold plates and connected by hoses to form a continueous pathway. The coolant absorbs heat from the mold (which has absorbed heat from the hot plastic) and keeps the mold at a proper temperature to solidify the plastic at the most efficient rate.To ease maintenance and venting, cavities and cores are divided into pieces, called inserts, and sub-assemblies, also called inserts, blocks, or chase blocks. By substituting interchangeable inserts, one mold may make several variations of the same part.More complex parts are formed using more complex molds. These may have sections called slides, that move into a cavity perpendicular to the draw direction, to form overhanging part features. When the mold is opened, the slides are pulled away from the plastic part by using st ationary “angle pins” on the stationary mold half. These pins enter a slot in the slides and cause the slides to move backward when the moving half of the mold opens. The part is then ejected and the mold closes. The closing action of the mold causes the slides to move forward along the angle pins.Some molds allow previously molded parts to be reinserted to allow a new plastic layer to form around the first part. This is often referred to as overmolding. This system can allow for production of one-piece tires and wheels.2-shot or multi-shot molds are designed to "overmold" within a single molding cycle and must be processed on specialized injection molding machines with two or moreinjection units. This process is actually an injection molding process performed twice. In the first step, the base color material is molded into a basic shape. Then the second material is injection-molded into the remaining open spaces. That space is then filled during the second injection step with a material of a different color.A mold can produce several copies of the same parts in a single "shot". The number of "impressions" in the mold of that part is often incorrectly referred to as cavitation. A tool with one impression will often be called a single impression(cavity) mold.A mold with 2 or more cavities of the same parts will likely be referred to as multiple impression (cavity) mold.Some extremely high production volume molds (like those for bottle caps) can have over 128 cavities.In some cases multiple cavity tooling will mold a series of different parts in the same tool. Some toolmakers call these molds family molds as all the parts are related.Effects on the material propertiesThe mechanical properties of a part are usually little affected. Some parts can have internal stresses in them. This is one of the reasons why it's good to have uniform wall thickness when molding. One of the physical property changes is shrinkage. A permanent chemical property change is the material thermoset, which can't be remelted to be injected again.Tool MaterialsTool steel or beryllium-copper are often used. Mild steel, aluminum, nickel or epoxy are suitable only for prototype or very short production runs.Modern hard aluminum (7075 and 2024 alloys) with proper mold design, can easily make molds capable of 100,000 or more part life.Geometrical PossibilitiesThe most commonly used plastic molding process, injection molding, is used to create a large variety of products with different shapes and sizes. Most importantly, they can create products with complex geometry that many other processes cannot. There are a few precautions when designing something that willbe made using this process to reduce the risk of weak spots. First, streamline your product or keep the thickness relatively uniform. Second, try and keep your product between 2 to20 inches.The size of a part will depend on a number of factors (material, wall thickness, shape,process etc.). The initial raw material required may be measured in the form of granules, pellets or powders. Here are some ranges of the sizes.MachiningMolds are built through two main methods: standard machining and EDM. Standard Machining, in its conventional form, has historically been the method of building injection molds. With technological development, CNC machining became the predominant means of making more complex molds with more accurate mold details in less time than traditional methods.The electrical discharge machining (EDM) or spark erosion process has become widely used in mold making. As well as allowing the formation of shapes that are difficult to machine, the process allows pre-hardened molds to be shaped so that no heat treatment is required. Changes to a hardened mold by conventional drilling and milling normally require annealing to soften the mold, followed by heat treatment to harden it again. EDM is a simple process in which a shaped electrode, usuallymade of copper or graphite, is very slowly lowered onto the mold surface (over a period of many hours), which is immersed in paraffin oil. A voltage applied between tool and mold causes spark erosion of the mold surface in the inverse shape of the electrode.CostThe cost of manufacturing molds depends on a very large set of factors ranging from number of cavities, size of the parts (and therefore the mold), complexity of the pieces, expected tool longevity, surface finishes and many others. The initial cost is great, however the piece part cost is low, so with greater quantities the overall price decreases.Injection processSmall injection molder showing hopper, nozzle and die area With Injection Molding, granular plastic is fed by gravity from a hopper into a heated barrel. As the granules are slowly moved forward by a screw-type plunger, the plastic is forced into a heated chamber, where it is melted. As the plunger advances, the melted plastic is forced through a nozzle that rests against the mold, allowing it to enter the mold cavity through a gate and runner system. The mold remains cold so the plastic solidifies almost as soon as the mold is filled.Injection Molding CycleThe sequence of events during the injection mold of a plastic part is called the injection molding cycle. The cycle begins when the mold closes, followed by the injection of the polymer into the mold cavity. Once the cavity is filled, a holding pressure is maintained to compensate for material shrinkage. In the next step, the screw turns, feeding the next shot to the front screw.This causes the screw to retract as the next shot is prepared. Once thepart is sufficiently cool, the mold opens and the part is ejected.Molding trialWhen filling a new or unfamiliar mold for the first time, where shot size for that mold is unknown, a technician/tool setter usually starts with a small shot weight and fills gradually until the mold is 95 to 99% full. Once this is achieved a small amount of holding pressure will be applied and holding time increased until gate freeze off (solidification time) has occurred. Gate solidification time is an important as it determines cycle time, which itself is an important issue in the economics of the production process. Holding pressure is increased until the parts are free of sinks and part weight has been achieved. Once the parts are good enough and have passed any specific criteria, a setting sheet is produced for people to follow in the future. The method to setup an unknown mold the first time can be supported by installing cavity pressure sensors. Measuring the cavity pressure as a function of time can provide a good indication of the filling profile of the cavity. Once the equipment is set to successfully create the molded part, modern monitoring systems can save a reference curve of the cavity pressure. With that it is possible toreproduce the same part quality on another molding machine within a short setup time.Tolerances and SurfacesMolding tolerance is a specified allowance on the deviation in parameters such as dimensions, weights, shapes, or angles, etc. To maximize control in setting tolerances there is usually a minimum and maximum limit on thickness, based on the process used.Injection molding typically is capable of tolerances equivalent to an IT Grade of about 9–14. The possible toleranceof a thermoplastic or a thermoset is ±0.008 to ±0.002 inches. Surface finishes of two to four microinches or better are can be obtained. Rough or pebbled surfaces are also possible.Lubrication and CoolingObviously, the mold must be cooled in order for the production to take place. Because of the heat capacity, inexpensiveness, and availability of water, water is used as the primary cooling agent. To cool the mold, water can be channeled through the mold to account for quick cooling times. Usually a colder mold is more efficient because this allows for faster cycle times. However, this is not always true because crystalline materials require the opposite: a warmer mold and lengthier cycle time.InsertsMetal inserts can be also be injection molded into the workpiece. For large volume parts the inserts are placed in the mold using automated machinery. An advantage of using automated components is that the smaller size of parts allows a mobile inspection system that can be used to examine multiple parts in a decreased amount of time. In addition to mounting inspection systems on automated components, multiple axial robots are also capable of removing parts from the mold and place them in latter systems that can be used to ensure quality of multiple parameters. The ability of automated components to decrease the cycle time of the processes allows for a greater output of quality parts.Specific instances of this increased efficiency include the removal of parts from the mold immediately after the parts are created and use in conjunction with vision systems. The removal of parts is achieved by using robots to grip the partonce it has become free from the mold after in ejector pins have been raised. The robot then moves these parts into either a holding location or directly onto an inspection system, depending on the type of product and the general layout of the rest of the manufacturer's production facility. Visions systems mounted on robots are also an advancement that has greatly changed the way that quality control is performed in insert molded parts. A mobile robot is able to more precisely determine the accuracy of the metal component and inspect more locations in the same amount of time as a human inspector.注塑成型注射制模（Injection moldin）是一种生产由热塑性塑料或热固性塑料所构成的部件的过程。
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附录外文资料与中文翻译外文资料：China's mold industry and its development trend The mold is the manufacturing industry important craft foundation, in our country, the mold manufacture belongs to the special purpose equipment manufacturing industry. China although very already starts to make the mold and the use mold, but long-term has not formed the industry. Straight stabs 0 centuries 80's later periods, the Chinese mold industry only then drives into the development speedway. Recent years, not only the state-owned mold enterprise had the very big development, the three investments enterprise, the villages and towns (individual) the mold enterprise's development also quite rapid .Although the Chinese mold industrial development rapid, but compares with the demand, obviously falls short of demand, its main gap concentrates precisely to, large-scale,complex, the long life mold domain. As a result of in aspect and so on mold precision, life, manufacture cycle and productivity, China and the international average horizontal and the developed country still had a bigger disparity, therefore, needed massively to import the mold every year .The Chinese mold industry except must continue to sharpen the productivity, from now on will have emphatically to the profession internal structure adjustment and the state-of-art enhancement. The structure adjustment aspect, mainly is the enterprise structure to the specialized adjustment, the product structure to center the upscale mold development, to the import and export structure improvement, center the upscale automobile cover mold forming analysis and the structure improvement, the multi-purpose compound mold and the compound processing and the laser technology in the mold design manufacture application, the high-speed cutting, the superfinishing and polished the technology, the information direction develops .The recent years, the mold profession structure adjustment and the organizational reform step enlarges, mainly displayed in, large-scale, precise, complex, the long life, center the upscale mold and the mold standard letter development speed is higher than the common mold product; The plastic mold and the compression casting mold proportion increases; Specialized mold factory quantity and its productivity increase; "The three investments" and the private enterprise develops rapidly; The joint stock system transformation step speeds up and so on. Distributes from the area looked, take Zhujiang Delta and Yangtze River delta as central southeast coastal area development quickly to mid-west area, south development quickly to north. At present develops quickest, the mold produces the most centralized province is Guangdong and Zhejiang, places such as Jiangsu, Shanghai, Anhui and Shandong also has a bigger development in recent years .Although our country mold total quantity had at present achieved the suitable scale, the mold level also has the very big enhancement, after but design manufacture horizontal overall rise and fall industry developed country and so on Yu De, America, date, France, Italy many. The current existence question and the disparity mainly display in following several aspects:(1) The total quantity falls short of demandDomestic mold assembling oneself rate only ,about 70%. Low-grade mold , center upscale mold assembling oneself rate only has 50% about .(2) The enterprise organizational structure, the product structure, the technical structure and the import and export structure does not gather In our country mold production factory to be most is from the labor mold workshop which produces assembles oneself (branch factory), from produces assembles oneself the proportion to reach as high as about 60%, but the overseas mold ultra 70% is the commodity mold. The specialized mold factory mostly is "large and complete", "small and entire" organization form, but overseas mostly is "small but", "is specially small and fine". Domestic large-scale, precise, complex, the long life mold accounts for the total quantity proportion to be insufficient 30%, but overseas in 50% above 2004 years, ratio of the mold import and export is 3.7:1, the importand export balances the after net import volume to amount to 1.32 billion US dollars, is world mold net import quantity biggest country .(3) The mold product level greatly is lower than the international standardThe production cycle actually is higher than the international water broad product level low mainly to display in the mold precision, cavity aspect and so on surface roughness, life and structure .(4) Develops the ability badly, economic efficiency unsatisfactory.Our country mold enterprise technical personnel proportion low the level is lower, also does not take the product development, frequently is in the passive position in the market. Our country each mold staff average year creation output value approximately ,ten thousand US dollars, overseas mold industry developed country mostly 15 to 20 thousand US dollars, some reach as high as 25 to 30 thousand US dollars, relative is our country quite part of molds enterprises also continues to use the workshop type management with it, truly realizes the enterprise which the modernized enterprise manages fewTo create the above disparity the reason to be very many, the mold long-term has not obtained the value besides the history in as the product which should have, as well as the most state-owned enterprises mechanism cannot adapt the market economy, but also has the following several reasons: .(1) Country to mold industry policy support dynamics also insufficientlyAlthough the country already was clear about has promulgated the mold profession industrial policy, but necessary policy few, carried out dynamics to be weak. At present enjoyed the mold product increment duty enterprise nation 185, the majority enterprise still the tax burden is only overweight. The mold enterprise carries on the technological transformations introduction equipment to have to pay the considerable amount the tax money, affects the technology advancement, moreover privately operated enterprise loan extremely difficult .(2) Talented person serious insufficient, the scientific research development and the technical attack investment too urineMold profession is the technology, the fund, the work crowded industry, along with the time progress and the technical development, grasps the talented person which and skilled utilizes the new technology exceptionally short, the high-quality mold fitter and the enterprise management talent extremely is also anxious. Because the mold enterprise benefit unsatisfactory and takes insufficiently the scientific research development and the technical attack, the scientific research unit and the universities, colleges and institutes eye stares at is creating income, causes the mold profession invests too few in the scientific research development and the technical attack aspect, causes the mold technological development step not to be big, progresses not quick .(3) The craft equipment level to be low, also necessary is not good, the use factor lowrecent years our country engine bed profession progressed quickly, has been able to provide the quite complete precision work equipment, but compared with the overseas equipment, still had a bigger disparity. Although the domestic many enterprises have introduced many overseas advanced equipment, but the overall equipment level low are very more than the overseas many enterprises. As a result of aspect the and so on system and fund reason, introduces the equipment not not necessary, the equipment and the appendix not necessary phenomenon are extremely common, the equipment utilization rate low question cannot obtain the comparatively properly solution for a long time .(4) Specialization, standardization, commercialized degree low, the cooperation abilityBecause receives "large and complete" "small and entire" the influence since long ago, mold specialization level low, the specialized labor division is not careful, the commercialized degree is low. At present domestic every year produces mold, commodity mold minister 40% About, other for from produce uses for oneself. Between the mold enterprise cooperates impeded, completes the comparatively large-scale mold complete task with difficulty. Mold standardization level low, moldstandard letter use cave rare is low also to the mold quality, the cost has a more tremendous influence, specially has very tremendous influence .(5) To the mold manufacture cycle) the mold material and the mold correlation technology fallsThe mold material performance, the quality and the variety question often can affect the mold quality, the life and the cost, the domestically produced molding tool steel and overseas imports the steel products to compare has a bigger disparity. Plastic, plate, equipment energy balance, also direct influence mold level enhancement .At present, our country economy still was at the high speed development phase, on the international economical globalization development tendency is day by day obvious, this has provided the good condition and the opportunity for the our country mold industry high speed development. On the one hand, the domestic mold market will continue high speed to develop, on the other hand, the mold manufacture also gradually will shift as well as the transnational group to our country carries on the mold purchase trend to our country extremely to be also obvious. Therefore, will take a broad view the future, international, the domestic mold market overall development tendency prospect will favor, estimated the Chinese mold will obtain the high speed development under the good market environment, our country not only can become the mold great nation, moreover certainly gradually will make the powerful nation to the mold the ranks to make great strides forward. "15" period, the Chinese mold industry level not only has the very big enhancement in the quantity and the archery target aspect, moreover the profession structure, the product level, the development innovation ability, enterprise's system and the mechanism as well as the technology advancement aspect also can obtain a bigger development .The mold technology has gathered the machinery, the electron, chemistry, optics, the material, the computer, the precise monitor and the information network and so on many disciplines, is a comprehensive nature multi-disciplinary systems engineering. The mold technology development tendency mainly is the mold product to larger-scale, preciser, more complex and a more economical direction develops,the mold product technical content unceasingly enhances, the mold manufacture cycle unceasingly reduces, the mold production faces the information, is not having the chart, is fine, the automated direction develops, the mold enterprise to the technical integration, the equipment excellent, is producing approves the brand, the management information, the management internationalization direction develops. Our country mold profession still will have to enhance from now on the general character technology had :(1) To establish in the CAD/CAE platform the advanced mold design technology, enhances modernization which the mold designed, information, intellectualization, standardized level .(2) Establishes in the CAM/CAPP foundation the advanced mold processing technology and the advanced manufacture technology unifies, raises the automated level and the production efficiency which the mold processes .(3) The mold production enterprise's information management technology. For example PDM (product data management), ERP (enterprise resource management), MIS (mold manufacture management information system) and information network technology the and so on INTERMET platform application, the promotion and the development .(4) Are high speed, Gao Jing, the compound mold processing technology research and the application. For example the ultra fine ramming mold manufacture technology, the precise plastic and the compression casting mold manufacture technology and so on .(5) Enhances the mold production efficiency, reduces the cost and reduces the mold production cycle each kind of fast economical mold manufacture technology .(6) The advanced manufacture technology application. For example hot technology and so on flow channel technology, gas auxiliary technology, hypothesized technology, nanotechnology, rapid scanning technology, reversion project, parallel project in the mold research, the development, the processing process application .(7) The raw material the simulation technology which forms in the mold .(8) The advanced mold processing and the appropriation equipment research and the development .(9) The mold and the mold standard letter, the important auxiliary standardizedtechnology .(10) The mold and its the product examination technology.(11) High quality, the new mold material research and the development and itsthe correct application .(12) The mold production enterprise's modern management technology □Mold profession in "十15" period needs to solve the key essential technologyshould be the mold information, the digitized technology and precise, ultra fine,high speed, the highly effective manufacture technology aspect breakthrough Along with the national economy total quantity and the industry producttechnology unceasing development, all the various trades and occupations to the molddemand quantity more and more big, the specification more and more is also high.Although mold type many, but its development should be with emphasis both canmeet the massive needs, and has the comparatively high-tech content, specially atpresent domestic still could not be self-sufficient, needs the massive imports themold and can represent the development direction large-scale, precise, is complex,the long life mold. The mold standard letter type, the quantity, the level, theproduction a and so on have the significant influence to the entire mold professiondevelopment. Therefore, some important mold standard letters also must theprioritize, moreover its development speed should quickly to the mold developmentspeed, like this be able unceasingly to raise our country mold standardization level,thus improves the mold quality, reduces the mold production cycle, reduces the cost.Because our country mold product holds the bigger price superiority in theinternational market, therefore regarding the exportation prospect good moldproduct also should take key develops. According to the above required quantity big,the technical content is high, represents the development direction, the exportprospect good principle choice prioritize product, moreover chooses the product tohave at present to have the certain technology base, belongs has the condition, hasthe product which the possibility develops .According to "十15" the mold profession development plan, "十15" the period mold product development mainly has following several kind of the automobile cover mold(1)Ramming mold to occupyThe mold total quantity dish with emphasis above 40%. Automobile cover mold mainly for automobile necessary, also includes for the agriculture with the vehicle, the project machinery and the farm machinery necessary cover mold, it has the very big representation in the ramming mold, the mold mostly is large and middle scale, structure complex, the specification is high. For the passenger vehicle necessary cover mold, the request is in particular higher, may represent the ramming mold the level. This kind of mold our country had the certain technology base, already for middle-grade passenger vehicle necessary, but the level is not high, the ability is insufficient, at present satisfying rate only has one about the half. Center the upscale passenger vehicle cover mold main dependence import, has become the bottleneck which the automobile develops, enormous influence vehicle type development .(2)The precise ramming moldMulti- locations level was entering the mold and fine represents the ramming mold development direction, the precision request life request has been extremely high, mainly for the electronics industry, the automobile, the instrument measuring appliance, the electrical machinery electric appliance and so on formed a complete set. These two kind of molds, domestic had the suitable foundation, and has introduced the overseas technology and the equipment, the individual enterprise produces the product has achieved the world level, but the majority of enterprises still had a bigger disparity, the supply total quantity insufficient, the import were very many(3) The large-scale precise plastic moldPlastic mold accounts for the mold total quantity 10%, moreover this proportion also is rising. In the plastic mold necessary large-scale casts the mold for the automobile and the electrical appliances, necessary models for the integratedcircuit seals the mold, for the electronic information industry and the machinery and the packing necessary multilayer, the multi- cavities, the multi- material qualities, the multicolor precise note , and saves water the agricultural necessary plastic different molding for the new building materials to squeeze out the mold and the pipeline and the nozzle mold and so on, at present although had the suitable technology base and fast is developing, but the technical level and overseas still had a bigger disparity, the total quantity falls short of demand, Every year import amount reaches several hundred million US dollar.(4) The main mold standard to imitateeAt present domestically to have an greater output the mold standard letter mainly is the mold frame, the guidance, the throwout lever pushes the tube, the elastic part and so on. These products not only the domestic necessary massive need, the exportation prospect very is also good, should continue vigorously to develop. The nitrogen cylinder and the hot flow channel part main dependence import, should raise the level in the existing foundation, forms the standard and organization scale production.(5) The other high-tech content moldsOccupiesin the mold total quantity green 8% compression casting mold, large-scale thin wall precise compression casting technology content high, the difficulty is big. The magnesium alloy compression casting mold at present although just started, but the prospects for development were good, have the representation. The meridian rubber tire mold also is the development direction, detachable mold technology difficulty is biggest. With fast takes shape some fast pattern making technologies and the corresponding fast economical mold which the technology unifies has the very good prospects for development. These high-tech content molds in "十15" period also should the prioritize .中文翻译：我国模具工业现状及发展趋势模具是制造业的重要工艺基础，在我国，模具制造属于专用设备制造业。