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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。

外文翻译---一个注射模填充模拟的几何方法

本科毕业论文外文翻译外文译文题目（中文）：一个注射模填充模拟的几何方法学院: 机械自动化学院专业: 模具设计与制造学号:学生姓名:指导教师:日期: 2009.12International Journal of Machine Tools & Manufacture 45 (2005) 115–124A geometric approach for injection mould filling simulationC.K. Au*School of Mechanical and Production Engineering, Nanyang Technological University, 50Nanyang Ave, 639798 SingaporeReceived 15 March 2004; received in revised form 7 June 2004; accepted 15 June 2004国际期刊机床与制造45 (2005) 115-124一个注射模填充模拟的几何方法C.K. Au南洋理工大学机械生产工程学院，新加坡南阳路50号，639798 标准版本2004年3月15;修订版本2004年6月7;正常版本2004年6月15号摘要本文讨论一个关于研究起源于点源的流阵面在带障碍的有界腔内流动规律几何技巧方法。

该技术是基于这样的假设塑料零件壁厚与流速成正比。

复杂注塑模具的腔内的流动是由四种基本流型，即吸收，折射，衍射和合并。

结合这四个流动模式在注塑成型法迅速产成填充样式在塑料生产发展期方案设计阶段有益的。

虽然讨论的应用背景是塑料注射成型，但这个技术在许多领域也是适用的。

与行业一样重要的大部分工作的工具和模具在过去20年来很大程度上是发展的，这就是对具体的边界条件运用现成的仿真或优化。

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。

塑料注射成型外文文献翻译、中英文翻译、外文翻译

塑料注射成型外文文献翻译、中英文翻译、外文翻译外文翻译原文：Injection MoldingMany different processes are used to transform plastic granules, powders, and liquids into product. The plastic material is in moldable form, and is adaptable to various forming methods. In most cases 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 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 hydraulics, barrel temperaturevariations, 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 repeatable and fully automaticcycle. Molders strive to reduce or eliminate rejected parts in molding production. For injection molding of high precision optical 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 ejectionPlastic granules are fed into the hopper and through an in the injection cylinder where they are carried forward by the rotating screw. The rotation of the screw forces the granules under high pressure against the heated walls of the cylinder causing them to melt. As the pressure building up, the rotating screw is forced backward until enough plastic has accumulated to make the shot. The injection ram (or screw) forces molten plastic from the barrel, through the nozzle, sprue and runner system, and finally into the mold cavities. During injection, the mold cavity is filled volumetrically. When the plastic contacts the cold mold surfaces, it solidifies (freezes) rapidly to produce theskin layer. Since the core remains in the molten state, plastic follows through the core to complete mold filling. Typically, the cavity is filled to 95%~98% during injection. Then the molding process is switched over to the packing phase.Even as the cavity is filled, the molten plastic begins to cool. Since the cooling plastic contracts or shrinks, it gives rise to defects such as sink marks, voids, and dimensional instabilities. To compensate for shrinkage, addition plastic is forced into the cavity. Once the cavity is packed, pressure applied to the melt prevents molten plastic inside the cavity from back flowing out through the gate. The pressure must be applied until the gate solidifies. The process can be divided into two steps (packing and holding) or may be encompassed in one step(holding or second stage). During packing, melt forced into the cavity by the packing pressure compensates for shrinkage. With holding, the pressure merely prevents back flow of the polymer malt.After the holding stage is completed, the cooling phase starts. During, the part is held in the mold for specified period. The duration of the cooling phase depends primarily on the material properties and the part thickness. Typically, the part temperature must cool below the material’s ejection temperature. While cooling the part, the machine plasticates melt for the next cycle.The polymer is subjected to shearing action as well as the condition of the energy from the heater bands. Once the short is made, plastication ceases. This should occur immediately before the end of the cooling phase. Then the mold opens and the part is ejected.When polymers are fabricated into useful articles they are referred to as plastics, rubbers, and fibers. Some polymers, forexample, cotton and wool, occur naturally, but the great majority of commercial products are synthetic in origin. A list of the names of the better known materials would include Bakelite, Dacron, Nylon, Celanese, Orlon, and Styron.Previous to 1930 the use of synthetic polymers was not widespread. However, they should not be classified as new materials for many of them were known in the latter half of the nineteenth century. The failure to develop them during this period was due, in part, to a lack of understanding of their properties, in particular, the problem of the structure of polymers was the subject of much fruitless controversy.Two events of the twentieth century catapulted polymers into a position of worldwide importance. The first of these was the successful commercial production of the plastic now known as Bakelite. Its industrial usefulness was demonstrated in1912 and in the next succeeding years. T oday Bakelite is high on the list of important synthetic products. Before 1912 materials made from cellulose were available, but their manufacture never provided the incentive for new work in the polymer field such as occurred after the advent of Bakelite. The second event was concerned with fundamental studies of the nature polymers by Staudinger in Europe and by Carohers, who worked with the Du Pont company in Delaware. A greater part of the studies were made during the 1920’s. Staudinger’s work was primarily fundamental. Carother’s achievements led t o the development of our present huge plastics industry by causing an awakening of interest in polymer chemistry, an interest which is still strongly apparent today.The Nature of ThermodynamicsThermodynamics is one of the most important areas ofengineering science used to explain how most things work, why some things do not the way that they were intended, and why others things just cannot possibly work at all. It is a key part of the science engineers use to design automotive engines, heat pumps, rocket motors, power stations, gas turbines, air conditioners, super-conducting transmission lines, solar heating systems, etc.Thermodynamics centers about the notions of energy, the idea that energy is conserved is the first low of thermodynamics. It is starting point for the science of thermodynamics is entropy; entropy provides a means for determining if a process is possible.This idea is the basis for the second low of thermodynamics. It also provides the basis for an engineering analysis in which one calculates the maximum amount of useful that can be obtained from a given energy source, or the minimum amount of power input required to do a certain task.A clear understanding of the ideas of entropy is essential for one who needs to use thermodynamics in engineering analysis. Scientists are interested in using thermodynamics to predict and relate the properties of matter; engineers are interested in using this data, together with the basic ideas of energy conservation and entropy production, to analyze the behavior of complex technological systems.There is an example of the sort of system of interest to engineers, a large central power stations. In this particular plant the energy source is petroleum in one of several forms, or sometimes natural gas, and the plant is to convert as much of this energy as possible to electric energy and to send this energy down the transmission line.Simply expressed, the plant does this by boiling water andusing the steam to turn a turbine which turns an electric generator.The simplest such power plants are able to convert only about 25 percent of the fuel energy to electric energy. But this particular plant converts approximately 40 percent;it has been ingeniously designed through careful application of the basic principles of thermodynamics to the hundreds of components in the system.The design engineers who made these calculations used data on the properties of steam developed by physical chemists who in turn used experimental measurements in concert with thermodynamics theory to develop the property data.Plants presently being studied could convert as much as 55 percent of the fuel energy to electric energy, if they indeed perform as predicted by thermodynamics analysis.The rule that the spontaneous flow of heat is always from hotter to cooler objects is a new physical idea. There is noting in the energy conservation principle or in any other law of nature that specifies for us the direction of heat flow. If energy were to flow spontaneously from a block of ice to a surrounding volume of water, this could occur in complete accord with energy conservation. But such a process never happens. This idea is the substance of the second law of thermodynamics.Clear, a refrigerator, which is a physical system used in kitchen refrigerators, freezers, and air-conditioning units must obey not only the first law (energy conservation) but the second law as well.To see why the second law is not violated by a refrigerator, we must be careful in our statement of law. The second law of thermodynamics says, in effect, that heat never flowsspontaneously from a cooler to a hotter object.Or, alternatively, heat can flow from a cooler to a hotter object only as a result of work done by an external agency. We now see the distinction between an everyday spontaneous process, such as the flow of heat from the inside to the outside of a refrigerator.In the water-ice system, the exchange of energy takes place spontaneously and the flow of heat always proceeds from the water to the ice. The water gives up energy and becomes cooler while the ice receives energy and melts.In a refrigerator, on the other hand, the exchange of energy is not spontaneous. Work provided by an external agency is necessary to reverse the natural flow of heat and cool the interior at the expense of further heating the warmer surroundings.译文：塑料注射成型许多不同的加工过程习惯于把塑料颗粒、粉末和液体转化成最终产品。

文献翻译-注塑模具

附页1：英文及中文翻译英文1.Example 24,Injection Mold for an Angle FitingIf ejectors are located behind movable side sores or slides ,the ejector plate return safety checks whether the ejectors have been returned to the molding position.If this is not the case,the molding cycle is interrupted.This safety requires a switch on the mold that is actuated when the ejector plate is in the retracted position. The ejector plate return safety thus functions only if the molding cycle utilizes platen preposition, i.e..,after the molded parts have been ejected, the clamping unit closes to the point at which the ejector plate is returned to the molding position by spring force. Only then does the control system issue the “close mold”command. In molds requiring a long ejector stroke, spring return of the ejector plate is often not sure enough. For such cases, there is an ejector return mechanism that fulfills this function.Attachment of the ejector plate return safety is shown in Figs.1 to 7.This single-cavity mold is used to produce an angle fitting.Two long side cores meet at an angle of 90°.The somewhat shorter side core is pulled by a cam pin,while the longer core is pulled by a slide.The difficulty is that blade ejectors are located under the two cores and must be returned to the molding position after having Ejected the finished part before the two cores are set as the mold closes and possibly damage the blade ejectors .Possible consequences include not only broken blade ejectors but also a damaged cavity. Either of these could result in a lengthy interruption of production. For this reason, a helical spring that permits operation with platen prepostion is placed on the ejector rod. This spring then returns the ejector plate .To ensure proper operation, a microswitch is mounted to the clamping plate,while a pin that actuates the switch is mounted in the ejector plate.After connecting the cable with the switch housing of the movable clamping plate,the ejector plate return safety is complete.Example 25,Mold for Bushings with Concealed Gating2．Example 25, Mold for Bushings with Concealed GatingAflanged bushing is to be injection molded in such a way that any remnants ofthe gate are concealed or as inconspicuous as possible.The bushing would normally require a two-plate mold with a single parting line,The molded part would then be released and ejected along its axis, which coincides with the opening direction of the mold. The gate would be located on the outer surface of the flange since it is in contact with the mold parting line.In order to satisfy the requirement for an “invisible”gate,the cavities (two rows of four) are placed between slides carrying the cores even though there are no undercuts.From a central sprue the melt flows through conical runners in the cores to pinpoint gates located on the inner surface of the bushings. As the slides move during opening of the mold the gates are cleanly sheared off flush with the adjacent part surface. The flexibility of the plastic selected is sufficient to permit release of the end of the runner from the angled runner channel.The parts are now free and can drop out of the mold.3. Example 26,Injection Mold for the Valave Housing of a Water-Mixing Tap Made from PolyacetalA valve housing had to be designed and produced for a water-mixing tap.The problem when designing the tool resulted from the undercuts in four directions.Originally occurring considerable differences in wall thicknesses have been eliminated during optimization. Demands for high precision of the cylindrical vave seat in parti-cular wer negatively influenced by various recesses in the wall and adjoining partitions,which favored sink marks and ovalness.Polyaceta (POM) had been chosen as molding materia.The complete molded part had to have homogeneous walls,and be free from flow lines if at all possible, as it would be subjected to ever-changing contact with hot and cold water during an estimated long life span.Inadequately fused weld lines would be capable of developoing into weak spots and wer therefore to be avoided at all cost.Provision has been made for an electrically heated sprue bushing in order to avoid a long sprue,provide better movement energies for the melt and maintain its temperature until it enters the cavity.The resultant very short runner leads to the gate on the edge of the pipelike housing, to be hidden by a part that is subsequently fitted to cover it.The gating,the predetermined mold temperature,the wall thickness at the critical positions and the resultant shrinkage have been employed as the basis for dimensioning the part-forming components.Two cores each cross in the pipe-shaped housing,i.e.one core each penetrates another core.This obviously presents a danger spot should the minutest deviation occur from the specified time and movement-based coordination as well as from the accuracy in the mold.The hollow cores are kept in position by mechanical delay during the first phase of mold opening,while the crossing cores are each withdrawn by an angle pin . Mechanical actuation has been preferred over a hydraulic or pneumatic one in this case in order to exclude the danger of a sequencing error (the so-called human factor) during set-up and operation.The cores consist of a beryllium-copper alloy. They are cooled by heat conducting pins.4．Example 29,Injection Mold for the Housing of a Polypropylene Vegetable DicerMolded PartThe housing accommodates a cutting disc that is driven by a hand crank . The shaft of the crank drive is located in a bore in the housing. The underneath of the housing has a recess for accommodating a suction cap to attach the device to a table. The top of the housing has a filling shaft which supplies the cutting disc with the vegetables to be diced. A feed hopper will be attached to this filling shaft.The molded part weighs 386 g.MoldThe mold was designed so that the dicing chamber lies in the mold-opening direction.The housing base,the filling shaft and two other apertures are ejected with the aid of splits ,a core puller and slides.The slide,moved by the angle pin,forms the inside contour of the housing base .In the closed position,the split shoulder lies against punch and so forms the bore for attaching the suction cap to the housing base .The cylindrical slide lies in the mold parting line and each half is enclosed by the mold plates and.Guide strips lead the slide on the mold plate. The slide supports itself against the effect of the cavity pressure via the adjusting plate and the wedge. Bending of the wedge is prevented by the adjusting plate and the mold plate. The vegetable filling shaft and the passage to the dicing chamber are formed by the mobile core. Its movement is provided by the angle pin.Figure 7 shows the core guide in the guide strip.The inserted core is locked via the wedge and adjusting plate .The guide strip forms a rectangular opening in theside wall of the housing which lies half over and half under the mold parting line. It is moved by two angle pins and is locked in the closed state by two bolts. A guide strip which is bolted and doweled to the mold plate is guided in a T-solt.Finally, a slit has to be formed in the housing wall that penetrates a reinforcement there. Rectangular aperture and reinforcement are formed by the slide which is actuated by the angle pin and locked by the wedge.Two bars serve to guide the slide on the mold plate. Since the angle pins traverse out from the slide ,the core and the guide bars on mold opening, each is provided with ball catches that keep these guide elements in the “open” position. Bars and rolls support the plate on the clamp plate.Runner System/GatingThe sprue bushing lies on the axis of the housing bore, which accommodates the blade drive shaft.The end of the sprue bushing forms the face of an eye inside the dicing chamber that is a part of the crankshaft mount. A core pin protrudes into the bore of the sprue bushing and divides the sprue into three pinpoint gates.Mold Temperature ControlThe coolant is guided in bores and cooling channels in the mold plates, inserts and punches.The splits and offer sufficient space for accommodating cooling channels..Part Release/EjectionOn mold opening,the angle pins on the fixed mold side push the splits ,cores and slides on the moving side so far outward that they release the undercuts of the housing. The molded part remanis on the moving mold side.Ejector pins and ejector sleeve push the molded part out of the ejector-side mold cavities and off core pin. Since the ejector pins are contour-forming,they must be secured against twisting . On mold closing, the ejector system is brought into the injection molding position by ejector-plate return pins and buffer pins,and so too are the splits ,cores and slides by their respective angle pints.译文1．注塑模具角度为拟合如果喷射器是可移动的侧后面疮或幻灯片位于顶针板返回安全的喷射器是否已返回成型，这是不是这样，成型周期检查中断。

中英文文献翻译-注塑成型机

英文原文Injection molding machineInjection molding machine is plastic machine for short. It uses the thermal physical propertiesof plastics, the material from the hopper into the barrel, is barreled by heating coil heat, so the material will be melted, which is arranged by the external force under the action of the motor driving the rotation of the screw in the barrel. The material in the screw under the action of the screw groove, along the forward delivery and compaction, dual role the material in the heating and shear under gradually plasticizing, melted and homogenized, when the screw rotates, the material in the screw channel friction and shear force, the molten material is pushed to the screw head. At the same time, the screw with backward in the material, the screw head forming material storage space, completing the plasticizing process, then, screw in the injection cylinder piston thrust under the action of high speed, high pressure, in the material storage chamber, the melt through the nozzle to the mold cavity injection, cavity melt after pressing, cooling, solidification, mold in the mold closing mechanism of action next, open mold, and through the ejection device to finalize the design good products fall from the top die.Configuration according to the clamping member and the injection component type has horizontal, vertical, angle type three(1) Horizontal injection molding machine: horizontal injection molding machine is the most common type. Its characteristic is the center line injection assembly and clamping assembly center line of concentric or consistent, also with the parallel to the mounting surface. It has the advantages of low center of gravity, steady work, mold installation, operation and repair, which are convenient, the mold opening big, small occupied space height; but covers an area of large. (2) Vertical injection molding machine: its characteristic is clamping device and injection device of the axis line arrangement and perpendicular to the ground. It also has the advantages of small occupied area, convenient assembly and disassembly of insert mold, easy installation, since the bucket into the material plasticization is evenly, easy to realize automation and machine automation line management. The disadvantage of it is the top product is not easy to fall off automatically, it often needs manual or other method to take out, and is not easy to realize full automatic operation and large products injection; machine height, feeding, inconvenient repair. (3) Angle type injection molding machine: injection device and a molding device axis are arranged vertically. According to the injection assembly center lines are vertical, horizontal and relative position of the vertical and horizontal installation, recumbent points: ① horizontal vertical, injection assembly line and plane parallel, and mold assembly center line and the base of vertical and horizontal, vertical; injection assembly center line and the surface vertical, and die assembly center line and the reference surface. The advantages of angle type injection machine has theadvantages of both horizontal and vertical injection molding machine, special apply to the mold opening side gate asymmetric geometry products.At present, the injection device are common cylinder form and double cylinder form, I plant the injection molding machine is double cylinder form, and is directly driven by a hydraulic motor of screw in injection molding. Because of different manufacturers, different types of machine components are not the same; the following will make a concrete analysis of our factory with machine.The working principle is: the plastic, screw in plastic parts in the drive the main shaft to rotate through the hydraulic motor, spindle end is connected with the screw, and the other end of the hydraulic motor key connection, screw rotation, plasticity and melt classified pushed to the storage chamber cylinder front, at the same time, screw back in the reaction material, and through the thrust bearing the thrust seat back, pulling the piston rod through the nut straight back. To complete the measurement, injection, the injection cylinder rod chamber oil inlet through the bearing to push the piston rod to complete the action, the rod chamber piston oil inlet to push the piston rod and screw and finish the injection.The work principle of screw plasticizing components: performs, screw rotation, from the material inlet into the screw groove material advancing continuously forward, heating ring through the barrel wall of the heat transfer to the spiral groove material, solid material in the dual role of external heating and screw rotational shear, and through the thermal process functional section of screw, achieving the plasticizing and melting, melting away the check ring around the screw head, front end through the channel into the screw, and generates backpressure, push the screw after the shift measurement complete melt, at the time of injection screw up, piston effect, with rapid advancement, in the cylinder, will melt reservoir material in the chamber through the nozzle into the mold.Screw plasticizing components generally have the following characteristics:The screw has two functions of plasticizing and injection;The screw in plastic, only for the plasticThe plastics in plasticizing process, thermal process through than extrusion;The screw on the plasticizing and injection were to occur, axial displacement, and screw in working state of intermittent when to stop, thus forming a non - stability of screw plasticizing process.(1) ScrewScrew is a key component of plastic parts, direct contact with plastic, plastic through the effective length of the screw channel, after the heat for a long time, must go through 3 states (glass, behavior, viscous state) transformation, geometric parameters, geometry, length of functional section of screw will directly affect the transmission efficiency and the plasticizing quality of plastic, will ultimately affect the quality of injection molding cycle and product.Compared with the extrusion screw, plastic screw has the following characteristics:The injection screw length-diameter ratio and compression ratio is small;Screw groove of injection screw is section of the deep;The injection screws feeding sections is longer, and are short;The injection screw work, plasticizing capacity and melt temperature will vary with the axial displacement screw and change.(I) classification, screwInjection screw according to the plastic adaptability, can be divided into general and special screw, general also called conventional screw, can be processed with low viscosity, most of the thermoplastic, civil plastic crystalline and amorphous and engineering plastics, is the most basic form of the screw, and the corresponding and special screw, is used to process with ordinary screw processing hard plastic; according to the screw structure and geometry characteristics, can be divided into conventional screw and screw, the conventional screw is also known as the three section screw, is the basic form of the screw, screw form has many kinds, such as separation screw, screw, wavy shunt screw, no metering section of screw.The conventional screw thread effective length is usually divided into feeding sections (conveying), the compression section (Plastics segment), and metering section (averaging period), according to the plastic properties of different, can be divided into gradual, mutation type and general type screw.The tapered screw: compression long, plasticizing energy transfer for PVC relaxation, poor thermal stability of plastic.The mutant compression screw: short, plasticizing energy conversion is more acuteness, used for polyolefin, PA crystalline plastics.The general purpose screw: adaptability is strong, and can be suitable for processing a variety of plastic, avoid frequent replacement of the screw, increase production efficiency.DS screw diameter, screw diameter directly affect the plasticizing capacity, will directly affect the injection volume, therefore, injection volume of injection molding machine the screw diameter is large.L/ds - screw length to diameter ratio. L is the effective length of screw thread part of the screw, the ratio of length to diameter is larger, the length of that thread, directly affect the thermal process of material in the screw, the ability to influence the absorption of energy, while the energy source has two parts: one part is the external heating coil to the barrel, and another part is friction thermal and shear heat generated by the rotation of the screw, the external mechanical energy conversion, therefore, L/ds directly affect the melting effect of material and melt, but if L/ds is too large, the transmission torque increase, increased energy consumption.L1 - feeding length. The feeding section is also called conveying or feed section, in order to improve the transport capacity, screw groove surface must be smooth, the length of the L1 shallensure that the material conveying length too short enough, because L1 will lead to premature melting material, thus it is difficult to guarantee the transportation conditions of stabilizing pressure, will be difficult to ensure the screw later. Plastic under their own gravity from the hopper to slip into the screw, screw rotation, the thrust surface friction in the barrel and screw groove under the action of the material is compressed into a solid, nut intensive, the relative motion along the direction of the thread, this section, plastic solid state, namely the glass state.The depth of screw channel H1 - feed section. H1 deep, is receiving materials, improving the feeding quantity and plasticizing capacity, but will affect the shear strength of material plasticization and screw root, general H1 ≈ (0.12 ~ 0.16) ds.L3 - melting length. Melting section called homogeneous section or the measuring section, melt further homogenization, uniform temperature in the channel of L3 segment, uniform composition, the formation of good quality of melt, the length of L3 is helpful to melt in the screw groove fluctuations, stable pressure, causes the material to feed evenly extruded from the screw head, so it is also called the metering section. L3 short time, help to improve the general screw plasticizing capacity, L3= (4 ~ 5)ds.H3 - melting section of spiral groove depth, H3 small, shallow groove, improves the plasticizing effect of plastic melt, to melt homogenization, but H3 is too small will lead to higher shear rate, and shear heat is too large, causing degradation of the molecular chain, the effect of melt quality,; conversely, if the H3 is too large, the perform, enhanced flow screw back pressure generated, will reduce the plasticizing capacity.L2 - plasticizing period (compression) length of thread. The tapered space material continuously under compression, shear and mixing effect, material from the L2 point, molten pool increased, to the point of weld pool has been occupying the entire screw groove, the material from the glass state through viscoelastic state transition to a viscous state, namely this segment, the plastic is state of coexistence in the particles with a molten body. The length of L2 will affect the transformation of the material from the glassy to viscous flow state, is too short will not change, plugging in the terminal segment of the L2 formation of high pressure, torque or axial force of solid material; too long will increase the screw torque and unnecessary consumption, general L2= (6 ~ 8) ds. For the crystalline plastics, material melting point, melting a narrow range, L2 can be shorter, generally (3 ~ 4) ds, for heat-sensitive plastic, this section Kvetching.S - Pitch, the size effect of helix angle, thus affecting the transport efficiency of screw, general S ≈ ds.E - Compression ratio. ε =h1/h3, namely the feeding section of spiral groove depth H1 and the melting section of spiral groove depth ratio of h3. E, will enhance the shear effect, but will weaken the plasticizing capacity, generally speaking, ε slightly smaller as well, to help improve the plasticizing capacity and increase the adaptability to raw materials, for crystalline plastics, the compression ratio is 2.6~3.0. For low viscosity and thermal stability of plastic, can choose thehigh compression ratio and high viscosity; thermal sensitivity plastic, should choose low compression rate.(2) The screw headIn the injection screw, screw head is: the plastic, can be good plastic melt and releasing to the storage chamber, and in high pressure injection, and can effectively close the melt front screw head, prevent backflow.The screw head is divided into two categories, with check ring and not the inverse ring with the check, the check ring, a plastic screw, melt homogenizing section will check ring away, through the gap formation and the screw head, into the storage chamber, injection pressure, melt screw the head of the formation of thrust, the non-return valve return channel plugging, prevent backflow. For some high viscosity materials such as PMMA, PC, AC or poor thermal stability of PVC material, in order to reduce the retention time of shearing and material, can not check ring, but this injection will produce reflux, prolonging holding time.On the screw head requirements:The screw head to be flexible smooth;The check ring and the cylinder to be suitable with the gap, to prevent melt flow, and flexible; The existing flow section is enough, but also to ensure the check ring face a return force, making fast closed at the time of injection;The structure should be easy disassembly, convenient cleaning;The direction of the screw thread screw and screw in screw head instead, prevent a plastic screw head loose.(3) Cylinder(I), the barrel structureCylinder is an important part of plastic parts; interior screw is arranged outside the heating coil, under complex stress and thermal stress.(II), the feeding portStructure feeding port directly affects feed effect and plastic parts of the feeding ability, injection molding machine most by gravity feed material in hopper, simple manufacture, but feed the negative; the feed material and the screw contact angle, contact area is large, can improve the feed efficiency, is not easy in the hopper into bridge hole.(III), cylinder wall thicknessCylinder wall thickness is of sufficient strength and stiffness, because the barrel to melt and gas pressure, and the barrel length to diameter ratio, cylinder requires enough heat capacity, so the cylinder walls have a certain thickness, otherwise it is difficult to ensure that the temperature stability; but if it is too thick, barrel bulky, waste material, the thermal inertia of large, slow temperature rise, temperature regulation of delay larger.(IV), cylinder clearanceCylinder gap refers to the single gap barrel wall and screw diameter, the gap is too large, plasticizing capacity is reduced, injected back into the discharge increases, injection time, causing material degradation in the process; if it is too small, the thermal expansion effect on the screw and barrel friction, energy consumption increased, even death card, this gap delta = (0.002~0.005) ds.(V), the material heating and cooling tubeInjection molding machine barrel heating with electric resistance, ceramic heating, cast aluminum heating, should be reasonably arranged according to the application and processing of materials, commonly used has the resistance heating and ceramic heating, to comply with the requirements of injection molding process, the barrel to subsection control, small 3, large machine 5.Cooling refers to the feeding mouth is cooling, because the feeding mouth if the temperature is too high, the solid in the feeding mouth "bridge", blocking the outlet, thus affecting the transport efficiency of feed section, so the cooling water jacket is arranged in the cooling it. Our factory is through the cooling circulating water cooling of the feed inlet.(4) Nozzle(I) function of spray nozzleThe nozzle is an important part of connecting plasticizing device and mold flow; nozzle has a variety of functions:The perform, establishment of backpressure, degassed, prevent melt salivation, improve plasticizing capability and measurement precision;The injection mold, forming the contact pressure and the main cast, keep good contact with pouring nozzle sleeve, forming a closed channel, to prevent the plastic melt under high pressure overflow;injection, establish the melt pressure, shear stress, and the pressure head into the velocity head, the increase of shear rate and temperature, enhance mixing and homogenizing;Changing the nozzle structure to match the mold and plasticizing device, a new type of flow channel or injection system;The nozzle also bears the thermostat, thermal insulation and cutting function;The reducing melts in the import and export of the viscoelastic effect and the eddy loss, in order to stabilize its flow;The holding pressure, easy to mold products of feeding, and the cooling shaping increased reflow resistance, reduce or prevent the melt in the cavity to return.(II) The basic form, nozzleNozzle can be divided into straight-through nozzle, locking type nozzle, hot runner nozzle and the flow nozzle, the present stage our factory are straight-through nozzle.Straight-through nozzle is the nozzle is widely applied, its characteristic is the direct and main casting mold nozzle spherical contact, the nozzle radius and the channel than the mold to be small, injection pressure, melt directly through the mold runner system is filled into the cavity, fast speed, low pressure loss, manufacturing and installation are all relatively convenient.Locking type nozzle is mainly to solve the problem through the nozzle salivation, suitable for low viscosity polymer (such as PA) processing. In the closing the nozzle plastic, prevent melt salivation phenomenon, and when the injection and injection pressure to open, so that melt into the mold cavity.2 injection cylinderIts working principle is: the injection cylinder into the oil, the piston drives the piston rod and the bearing is arranged on the thrust seat, drive screwPush the screw forward or backward. Through the nut piston rod head, can adjust the timing of two parallel to the axial position of the piston rod and the injection screw axial position.3 thrust bearingInjection, thrust bearing thrust shaft driven by screw injection; while the plastic, the oil motor drive screw rotation to achieve thrust shaft drives the perform.4 cylindersWhen a moving oil cylinder into the oil, forward seat injection or the back action, and to ensure the injection nozzle and mould the main cast set of circular arc closely contact, the injection pressure can seal the melt.The 5 part accuracy requirements for injectionAfter the assembly, the components are arranged on the machine frame, must ensure that the nozzle and mold water sleeve is tightly bonding, in order to prevent overflow, the center line of injection parts requirements and the clamping parts of the center line of concentric; in order to ensure the accuracy of injection screw and barrel inner hole, must ensure that the two injection cylinder bore and the center cylinder hole is parallel with the center line of symmetry; in the horizontal plane, parallelism and symmetry for the center of a moving oil cylinder two guide holes also must ensure that the vertical machine, it must ensure that the two seat moving oil cylinder hole and a cylinder positioning the center hole is parallel with the center line of symmetry. Factors affecting the location accuracy of hole and shaft are associated parts size precision, geometric accuracy, precision and assembly precision.Each kind of plastic, has an ideal plastic processing temperature range, should control the processing temperature of barrel, which is close to the temperature range. Granular plastic from the hopper into the barrel, the first will arrive at a feeding section, in the feeding section will appear dry friction, when the plastic is heated, melting is not uniform, very easy to cause the barrel wall and screw wear surface. Similarly, the compression section and the entire segment, if the molten state disorder plastic uneven will result in increased wear.Speed should be adjusted properly. The friction force of these substances on the metal material is often much larger than the molten plastic. In the plastic injection molding, if using high speed in the shear stress on the plastic at the same time, it will also strengthen correspondingly more torn fibers, the torn fibers containing sharp end, to wear a large force to increase. Inorganic minerals on the surface of metal high-speed taxiing, the scraping is not a small role. So the speed should not be too high.In addition to check in plastic debris, the original purchase fresh plastic and no debris, but after weighing, transport, drying, mixing, especially to add recycling back material, there may be mixed with debris. Small as metal filings, as big as a heating ring nut clip, or clusters of warehouse key, mixed into the barrel had occurred, the screw damage is self-evident. (barrel of course also damage), therefore must install the magnetic iron material, strict management and monitoring. Moisture in plastics has a certain effect on the wear surface of the screw. If the plastic in injection unprecedented will eliminate all residual moisture, moisture into the screw compression section, they formed before melt blend in molten plastic with high temperature and high pressure "steam particles", with the injection process screw propulsion, from homogeneous section until the screw head, these "steam" particle, pressure drop and expansion in the injection process, the impurities such as a fine grain, rubbing on the wall damage. In addition, for some types of plastic, under high temperature and high pressure, the water may become a catalyst for cracking of plastic, harmful impurities can corrode the metal surface. Therefore, the drying work plastic injection before, not only has a direct relationship to the product quality, but also affects the service life of the screw.中文译文注塑成型机注塑成型机简称注塑机。

模具设计外文翻译--注射／压缩流体组合模塑的数值模拟

附录二：外文翻译原件及翻译稿Numerical simulation of injection/compression liquid composite moldingPart 1. Mesh generationK.M. Pillai a, C.L. Tucker III, F.R a. Phelan Jr ba Department of Mechanical and Industrial Engineering, University of Illinois,1206 W. Green Street, Urbana, IL61801, USAb Polymer Composites Group, Polymers Division, Building 224, Room B108, National Institute ofStandards and Technology, Gaithersburg, MD20899, USAAccepted 14 June 1999───────────────────────────────────────AbstractThis paper presents a numerical simulation of injection/compression liquid composite molding, where the fiber preform is compressed to a desired degree after an initial charge of resin has been injected into the mold. Due to the possibility of an initial gap at the top of the preform and out-of-plane heterogeneity in the multi-layered fiber preform, a full three-dimensional (3D) flow simulation is essential. We propose an algorithm to generate a suitable 3D finite element mesh, starting from a two-dimensional shell mesh representing the geometry of the mold cavity. Since different layers of the preform have different compressibility, and since properties such as permeability are a strong function of the degree of compression, a simultaneous prediction of preform compression along with the resin flow is necessary for accurate mold filling simulation. The algorithm creates a coarser mechanical mesh to simulate compression of the preform, and a finer flow mesh to simulate the motion of the resin in the preform and gap. Lines connected to the top and bottom plates of the mold, called spines, are used as conduits for the nodes. A method to generate a surface parallel to a given surface, thereby maintaining the thickness of the intermediate space, is used to construct the layers of the preform in the mechanical mesh. The mechanical mesh is further subdivided along the spines to create the flow mesh. Examples of the three-dimensional meshes generated by the algorithm are presented. 1999 Elsevier Science Ltd. All rights reserved.Keywords: Liquid composite molding (LCM); E. Resin transfer molding (RTM)───────────────────────────────────────1. IntroductionLiquid composite molding (LCM) is emerging as an important technology to make net-shape parts of polymer-matrix composites. In any LCM process, a preform of reinforcing fibers is placed in a closed mold, then a liquid polymer resin is injected into the mold to infiltrate the preform. When the mold is full, the polymer is cured by a crosslinking reaction to become a rigid solid. Then the mold is opened to remove the part. LCM processes offer a way to produce high-performance composite parts using a rapid process with low labor requirement.This paper deals with a particular type of LCM process called injection/compression liquid composite molding (I/C-LCM). In I/C-LCM, unlike other types of LCM processes, the mold is only partially closed when resin injection begins. This increases the cross-sectional area availablefor the resin flow, and decreases flow resistance by providing high porosity in the reinforcement. Often, the presence of a gap at the top of the preform further facilitates the flow. After all of the resin has been injected, the mold is slowly closed to its final height, causing additional resin flow and saturating all portions of the preform. The I/CLCM process fills the mold more rapidly, and at a lower pressure than the other LCM processes that use injection alone.Complete filling of the mold with adequate wetting of the fibers is the primary objective of any LCM mold designer; incomplete filling in the mold leads to production of defective parts with dry spots. There are many factors which affect the filling of the mold: permeability of the preform, presence of gaps in the mold to facilitate resin flow, arrangement of inlet and outlet gates, injection rates of resin from different inlet ports, etc. Often it is not possible for the mold designer to visualize and design an adequate system for resin infusion by intuition alone, and mold filling simulations are used to optimize mold performance. The situation in I/C-LCM is more complex than ordinary LCM because of compression of the mold during the filling operation. As a result, numerical simulation of the mold filling process in I/C-LCM becomes all the more important.I/C-LCM fiber preforms frequently comprise layers of different reinforcing materials such as biaxial woven fabrics, stitch-bonded uniaxial fibers, random fibers. Each type of material has a unique behavior as it is compressed in the mold. When such different materials are layered to form the preform, each of them will compress by different amounts as the mold is closed. This behavior is illustrated in Fig. 1, which shows a small piece of a mold. Here the lighter center layer deforms much more than the darker outer layer as the mold is closed.(B) After compression (A) Before compressionFig. 1. Uneven deformation of preform layers under compression.Capturing this deformation behavior during compression is critical to the accuracy of any I/C-LCM process model. Resin flows through the preform at all stages of compression, and the porosity and permeability of the preform are critical in determining the resin flow. The ratio of deformed volume to initial volume determines the porosity of each preform layer, and from this one can determine the layer's permeability, either from a theoretical prediction or a correlation of experimental data. Because of this strong coupling between the state of compression in a preform layer and its permeability, computations for fluid flow and preform compression have to be done simultaneously for mold filling simulations in I/C-LCM.Significant steps have already been taken to computationally model the mold filling in the I/C-LCM process. A computer program called crimson, is capable of isothermal mold fillingsimulation which involves simultaneous fluid flow and preform compression computations in the flow domain. But the initial capacity of crimson is limited to two-dimensional (2D) planar geometries where prediction of preform compression is straightforward. Deformation of the preform is modeled using the incremental linearized theory of elasticity; the mathematics simplifies due to reduction in the number of degrees of freedom (DOF) associated with displacement from the usual three to one along the thickness direction. However parts made by the I/C-LCM process typically have complicated three-dimensional shapes and this reduction of the mathematical complexity is no longer possible. The present paper describes our effort to expand the capability of crimson by enabling it to tackle any arbitrary non-planar three dimensional (3D) mold geometry.Most injection molding simulation programs read for the mold geometry in the form of a shell mesh. Even if it were possible to transmit the full geometrical information about the mold through a 3D mesh, it still is difficult to incorporate all the information of relevance to the process engineer. The latter needs to know the thicknesses of various layers of fiber mats and their corresponding porosities at each time step. As a result, it is very important that elements representing different layers of preform in the 3D finite element mesh fall within separate layered regions. Overlap of an element onto more than one region is not acceptable as the element has to carry the material properties, such as porosity, permeability, of only one fiber mat. Mesh-generators in state-of-the-art commercial software such as PATRAN are not designed to generate such a 3D mesh. Consequently, we decided to create a preprocessor suitable for I/C-LCM mold filling simulation.The objectives of this paper are to introduce basic ideas about modeling mold filling in 3D I/C-LCM parts, and to introduce an algorithm to generate a 3D finite element mesh from a given 2D shell mesh for preform and flow computations. In subsequent papers, we will model finite deformation of preform using the non-linear theory of elasticity, and use this information to model resin flow in an I/C-LCM mold.2. Generating a 3D mesh from the given 2D shell meshOur aim is to develop a preprocessor that can generate 3D finite element meshes for flow computations starting from a 2D shell mesh. We wish to allow the I/C-LCM process engineer to include all relevant information such as thicknesses of the layers of the preform, thickness of the gap, into the mesh.A - open gap everywhere C - just touching / partly compressedD - fully compressed everywhere B - open gap / just touchingFig. 2. A schematic describing the various stages of the compression/injection molding process. The top plate of the mold moves along theclamping vector, while the bottom plate is stationary. Stages A–C arethree possible starting positions of the top plate. Stage D shows the finalconfiguration of the mold when it is fully compressed.Fig.2 describes the three possible starting mold configurations (A-C) for a typical angular part geometry. Case A represents the starting configuration for the open mold injection/compression (I/C) molding, with ample gap between the top plate and preform. Cases B and C occur when the gap is partly or completely eliminated before the start of the injection process. In the former, the preform is completely uncompressed with gaps at a few places. In the latter, the gap is removed at the cost of partial compression of the preform in certain regions. In the present paper, mesh generation for configuration A only will be addressed. Once this mesh is created, cases B and C can be generated by solving for the mechanical compression of the preform.As we shall see in the subsequent papers, six-noded wedge elements and eight-noded brick elements are adequate for modeling both the resin flow and preform compression. Our mesh generation algorithm is designed to generate such elements from the three- and four-noded triangular and quadrilateral elements of the shell mesh.2.1. Mechanical and flow meshesDevelopment of the 3D mesh for flow computations from a given 2D shell mesh, representing the part geometry, is divided into two stages. In the first stage, an intermediate mechanical mesh is created, where the number of layers of elements equals the number of fiber mats in the lay-up, with the thickness of the mats equal to the height of those elements. Such a coarse mesh is adequate to track deformation of the mats during compression of the mold. In the second stage, the mechanical mesh is further subdivided along the thickness direction to create a more refined mesh, called the flow mesh, which is used for flow calculations.3. Basic concepts of mesh generation algorithmWe first introduce two basic ideas that form the backbone of our mesh generation algorithm: spines and parallel surfaces.3.1. Use of spinesOne of the salient features of our mesh generation technique is the use of spines to track the nodes of the 3D mechanical mesh. This is similar to the use of spines in the free boundary problems where they have been used to adapt the computational mesh with time. These spines are lines connecting node points of the top mold surface to their counterparts of the bottom mold surface.4. AlgorithmThe main actions carried out in our mesh generation algorithm are as follows:1. Read data describing the 2D shell mesh. The mesh data is read, along with the information important for process modeling such as direction of clamping, properties of fiber mats, initial gap provided at the top of the preform.2. Construct the upper surface of the final part. The upper surface is generated parallel to the input 2D shell mesh which represents the bottom, immovable surface of the mold. The inputthicknesses between the given and upper surfaces are taken to be the final thickness of the I/C-LCM mold (equal to the desired part thickness).5. Examples and discussionA computer program has been developed to implement the mesh generation algorithm, and tested for its efficacy and robustness. In the following sections, examples of the creation of 3D computational meshes from 2D shell meshes are presented. Since the thicknesses in the I/C-LCM parts are much smaller than their other dimensions, realistic meshes are relatively thin. To highlight important features of the algorithm, the thicknesses of the meshes are scaled up in the following examples. In each example, a gap that is a certain fraction of the total thickness of the uncompressed preform is provided between the upper surface of the preform and the top mold plate.6. Summary and conclusionsIn this paper, we present a methodology to create 3D finite element meshes for modeling mold filling in I/CLCM. We propose the concept of predicting preform compression using the coarse mechanical mesh, and predicting fluid flow using the finer flow mesh. A mesh-generating algorithm, to create the mechanical and flow meshes from a given shell mesh, is presented. This algorithm incorporates information about the position of fiber mat interfaces in a multi-layered preform, which is crucial for accurate modeling of the filling process. A technique to create surfaces parallel to any arbitrary shell mesh surface enables us to represent the interfaces accurately. Further, the use of spines in mesh generation reduces the number of unknowns at each node from three to one. The algorithm is used successfully to create the mechanical and flow meshes from two different shell meshes; its robustness is demonstrated by creating a 3D mesh from a shell mesh for an arbitrary mold shape. The need to refine the shell mesh in the region of a step change in the thickness of the mold is the main limitation of the algorithm. In subsequent papers, we will use the mechanical and flow meshes to simulate preform compression and resin flow during mold filling in I/C-LCM.注射／压缩流体组合模塑的数值模拟第一部分网格生成K.M. Pillai a, C.L. Tucker III, F.R a. Phelan Jr ba伊利诺斯大学机械工业工程系1206 W. Green Street, Urbana, IL61801, USAb国家标准与技术研究所，聚合物部，聚合物合成组Building 224, Room B108,Gaithersburg, MD 20899,USA收稿日期：1999年6月14日───────────────────────────────────────摘要文章介绍了注入模型中的树脂在一次初填充后其纤维预型件被压缩到所需的程度时，注射／压缩流体组合模塑的一种数值模拟。

模具塑料注射成型外文翻译外文文献英文文献

模具塑料注射成型外文翻译外文文献英文文献XXXThere are many different processing methods used to convert plastic pellets。

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thermoplastic materials XXX。

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XXX account for 30% of all XXX suitable for mass n。

when raw materials XXX in a single step of n。

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n machiningis not required for such products。

The us products produced include toys。

automotive parts。

household items。

and electronic consumer goods.Because plastic n molds have many variable nships。

it is a complex and us processing process。

The success of XXX appropriate steps。

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and increase product quality.XXX operator is to produce products that e first-rate products in the shortest time。

模具外文翻译外文文献英文文献注塑模

模具外文翻译外文文献英文文献注塑模The Injection Molding1、The injection moldingInjection molding is principally used for the production of the thermoplastic parts,although some progress has been made in developing a method for injection molding some thermosetting materials.The problem of injection a method plastic into a mold cavity from a reservoir of melted material has been extremely difficult to solve for thermosetting plastic which cure and harden under such conditions within a few minutes.The principle of injection molding is quite similar to that of die-casting.The process consists of feeding a plastic compound in powered or granular form from a hopper through metering and melting stages and then injecting it into a mold.After a brief cooling period,the mold is opened and the solidified part ejected.Injection-molding machine operation.The advantage of injection molding are：（ⅰ）a high molding speed adapter for mass production is possible；（ⅱ）there is a wide choice of thermoplastic materials providing a variety of useful properties；（ⅲ）it is possible to mold threads,undercuts,side holes,and large thin section.2、The injection-molding machineSeveral methods are used to force or inject the melted plastic into the mold.The most commonly used system in the larger machines is the in-line reciprocating screw,as shown in Figure 2-1.The screw acts as a combination injection and plasticizing unit.As the plastic is fed to the rotating screw,it passes through three zones as shown：feed,compression,and metering.After the feed zone,the screw-flight depth is gradually reduced,force theplastic to compress.The work is converted to heat by conduction from the barrel surface.As the chamber in front of the screw becomes filled,it forces the screw back,tripping a limit switch that activates a hydraulic cylinder that forces the screw forward and injects the fluid plastic into the closed mold.An antiflowback valve presents plastic under pressure from escaping back into the screw flight.The clamping force that a machine is capable of exerting is part of the size designation and is measured in tons.A rule-of-thumb can be used to determine the tonnage required for a particular job.It is based on two tons of clamp force per square inch of projected area.If the flow pattern is difficult and the parts are thin,this may have to go to three or four tons.Many reciprocating-screw machines are capable of handing thermosetting plastic materials.Previously these materials were handled by compression or transfer molding.Thermosetting materials cure or polymerize in the mold and are ejected hot in the range of 375°C～410°C.T hermosetting parts must be allowed to cool in the mold in order or remove them without distortion. Thus thermosetting cycles can be faster.Of course the mold must be heated rather than chilled,as with thermoplastics.3、Basic Underfeed MouldA simple mould of this type is shown in Figure3-1,and the description of the design and the opening sequence follows.The mould consists of three basic parts,namely：the moving half,the floating cavity plate and the feed plate respectively.The moving half consists of The moving mould plate assembly,support block,backing plate,ejector assembly and the pin ejection system.Thus the moving half in this design is identical with the moving half of basic moulds.The floating cavity plate,which may be of the integer or insert-bolster design,is located on substantial guide pillars（not shown）fitted in the feed plate.These guide pillars must be of sufficient length to support the floating cavity plate over its full movement and still project to perform the function of alignment between the cavity and core when the mould is being closed.Guide bushes are fitted into the moving mould plate and the floating cavity plate respectively.The maximum movement of the floating cavity plate is controlled by stop or similar device.The moving mould plate is suitably bored to provide a clearance for the stop bolt assembly.The stop bolts must be long enough to provide sufficient space between the feed plate and the floating cavity plate for easy removal of the feed system.The minimum space provide for should be 65mm just sufficient for an operator to remove the feed system by hand if necessary.The desire operating sequence is for the first daylight to occur between the floating cavity plate.This ensures the sprue is pulled from the sprue bush immediately the mouldis opened.T o achieve this sequence,springs may be incorporated between the feed plate and the floating cavity plate.The springs should be strong enough to give an initial impetus to the floating cavity plate to ensure it moves away with the moving half.It is normal practice to mount the springs on the guide pillars（Figure3-2）and accommodate them in suitable pocket in the cavity plate.The major part of the feed system（runner and sprue）is accommodated in the feed plate to facilitate automatic operation,the runner should be of a trapezoidal form so that once it is pulled from the feed plate is can easily beextracted.Note that if a round runner is used,half the runner is formed in the floating cavity plate,where it would remain,and be prevented from falling or being wiped clear when the mould is opened.Now that we have considered the mould assembly in the some detail,we look at the cycle of operation for this type of mould.The impressions are filled via the feed system（Figure3-1（a））and after a suitable dwell period,the machine platens commence to open.A force is immediately exerted by the compression springs,which cause the floating cavity plate to move away with the moving half as previously discussed.The sprue is pulled from the sprue bush by the sprue puller.After the floating cavity plate has moved a predetermined distance,it is arrested by the stop bolts.The moving half continues to move back and the moldings,having shrunk on to the cores,are withdrawn from the cavities.The pin gate breaks at its junction with the runner（Figure3-1（b））.The sprue puller,being attached to the moving half,is pulled through the floating cavity plate and thereby release the feed system which is then free to fall between the floating cavity plate and the feed plate.The moving half continues to move back until the ejector system is operated and the moldings are ejected （Figure3-1（c））.When the mould is closed,the respective plates are returned to their molding position and the cycle is repeated.4、Feed SystemIt is necessary to provide a flow-way in the injection mould to connect the nozzle（of the injection machine）to each impression.This flow-way is termed the feed system.Normally thefeed system comprises a sprue,runner and gate.These terms applyequally to the flow-way itself,and to the molded material which is remove from the flow-way itself in the process of extracted the molding.A typical feed system for a four-impression,two plate-type mould is shown in Figure4-1.It is seen that the material passes through the sprue,main runner,branch runner and gate before entering the impression.As the temperature of molten plastic is lowered which going through the sprue and runner,the viscosity will rise;however,the viscosity is lowered by shear heat generated when going through the gate to fill the cavity.It is desirable to keep the distance that the material has to travel down to a minimum to reduce pressure and heat losses.It is for this reason that careful consideration must be given to the impression layout gate’s design.4.1.SprueA sprue is a channel through which to transfer molten plastic injected from the nozzle of the injector into the mold.It is a part of sprue bush,which is a separate part from the mold.4.2.RunnerA runner is a channel that guides molten plastic into the cavity of a mold.4.3.GateA gate is an entrance through which molten plastic enters the cavity.The gate has the following function：restricts the flow and the direction of molten plastic；simplifies cutting of a runner and moldings to simplify finishing of parts；quickly cools and solidifies to avoid backflow after molten plastic has filled up in the cavity.4.4.Cold slug wellThe purpose of the cold slug well,shown opposite the sprue,is theoretically to receive the material that has chilled at the front of nozzle during the cooling and ejection phase.Perhaps of greater importance is the fact that it provides position means whereby the sprue bush for ejection purposes.The sprue,the runner and the gate will be discarded after a part is complete.However,the runner and the gate are important items that affect the quality or the cost of parts.5、EjectionA molding is formed in mould by injecting a plastic melt,under pressure,into animpression via a feed system.It must therefore be removed manually.Furthermore,all thermoplastic materials contract as they solidify,which means that the molding will shrink on to the core which forms it.This shrinkage makes the molding difficult to remove. Facilities are provided on the injection machine for automatic actuation of an ejector system,and this is situated behind the moving platen.Because of this,the mould’s ejector system will be most effectively operated if placed in the moving half of the mould,i.e. the half attached to the moving platen.We have stated previously that we need to eject the molding from the core and it therefore follows that the core,too,will most satisfactorily be located in the moving half.The ejector system in a mould will be discussed under three headings,namely：（ⅰ）the ejector grid;（ⅱ）the ejector plate assembly; and（ⅲ）the method of ejection.5.1、Ejector gridThe ejector grid（Figure5-1）is that part of the mould which supports the mould plate and provides a space into which theejector plate assembly can be fitted and operated.The grid normally consists of a back plate on to which is mounted a number of conveniently shaped “support blocks”.The ejector plate assembly is that part of the mould to which the ejector element is attached.The assembly is contained in a pocket,formed by the ejector grid,directly behind the mould plate.The assembly（Figure5-2）consists of an ejector plate,a retaining plate and an ejector rod.One end of this latter member is threaded and it is screwed into the ejector plate.In this particular design the ejector rod function not only as an actuating member but also as a method of guiding the assembly.Note that the parallel portion of the ejector rod passes through an ejector rod bush fitted in the back plate of the mould.5.2、Ejection techniquesWhen a molding cools,it contracts by an amount depending on the material being processed.For a molding which has no internal form,for example,a solid rectangular block,the molding will shrink away from the cavity walls,thereby permitting a simple ejection technique to be adopted.However,when the molding has internal form,the molding,as it cools,will shrink onto the core and some positive type of ejection is necessary.The designer has several ejection techniques from which to choose，but in general,the choice will be restricted depending upon the shape of the molding.The basic ejection techniques are as follows：（ⅰ）pin ejection（ⅱ）sleeve ejection（ⅲ）stripper plate ejection and（Ⅳ）air ejection.Figure 2-1aFigure 2-1bFigure 3-1Figure 3-2Figure 4-1aFigure 4-1bFigure 5-1Figure 5-2注塑模1、注塑模尽管成型某些热固性材料的方法取得了一定的进步，但注塑模主要（还是）用来生产热塑性塑件。

三维CAD注射模具设计外文翻译文献

三维CAD注射模具设计外文翻译文献(文档含中英文对照即英文原文和中文翻译)翻译:三维CAD知识在注塑模设计系统中的应用一、介绍近年来，塑料制品制造业发展迅速。

注射成型是一种非常流行的塑料零件成型方法。

注塑模具对产品质量和高效加工具有重要意义。

模具制造企业为了保持竞争优势，希望通过实现设计过程的自动化来缩短模具设计和制造的周期。

因此，计算机辅助注射模设计系统（caimds）的开发逐渐成为工业界和学术界研究的热点。

最近发表的论文表明，自动化模具设计的研究主要集中于单个组件的模具工艺。

例如，翁等人以及拉维集中研究送料系统；王等人主要研燃油喷射系统；其他人则关注整体设计。

通用注塑模系统的研究可分为两个领域：功能、概念、模具初步设计和模具自动生成算法。

注塑模具的功能、概念和初步设计主要用于前模设计。

此类设计包括选择一个合适的模架、安排型腔布局、设计分流道以及设计浇口，目的是为了对于一个特定的要求提出大量不同的产品理念。

布里顿等人通过提出功能-环境-行为-结构模型，从功能的角度解决了注塑模具设计的问题。

这项研究制造出了很多设计的互换件。

科斯塔和杨提出了产品范围模型，以支持不同设计案例中设计信息的再利用。

产品范围模型的总体结构大致是从设计功能方面定义的，该功能的设计与各系列设计方案以及潜在方案与知识链之间的内在联系息息相关。

叶等人提出了一种自动化初始设计的算法，能够计算出型腔数并自动化地设计出型腔。

注塑模具的初始设计涉及对模具组件广泛的实验知识。

因此，许多研究人员采用以实验知识为基础的方法。

他们开发了一些基于实验知识的系统，用于推荐塑料材料的选择、捕捉注塑模具零件的设计特征、分析塑性、自动生成模具设计过程和开发产品模具设计。

这类系统包括Geres和plassex（阿格拉沃尔和瓦苏德万),eimpplan-1（秦和王),cadfeed(翁等人),icad(辛魁格兰那),ikmould(莫克等人)以及卓克索大学的知识库系统(曾等人)。

模具制造专业外文翻译--注射成型应用

外文原文Injection Molding ApplicationsIntroductionThe use of plastic tooling in injection molding occurs within the field of Rapid Tooling (RT), which provides processes that are capable of producing injection mold tooling for low volume manufacturing at reduced costs and lead times. Such tooling allows the injection molding of parts in the end-use materials for functional prototype evaluation, short series production, and the validation of designs prior to hard tooling commitment. The term Rapid Tooling is somewhat ambiguous – its name suggests a tooling method that is simply produced quickly. However, the term is generically associated with a tooling method that in some form involves rapid prototyping technologies.Investigation and application of Stereo lithography (SL) to produce mold cavities for plastic injection molding primarily began in the 1990s. Initially the process was promoted as a quick route to soft tooling for injection molding (a tool to produce a relative low number of parts). The advantages of this have been somewhat diluted as other mold production technologies, such as high speed machining, have progressed,but other unique capabilities of the process have also been demonstrated.Stereo lithography has several process capabilities that are particularly advantageous for injection mold tooling, but we should also appreciate that is accompanied by some significant restrictions. This chapter introduces several aspects of the process accompanied by a discussion of its pros and cons, along with examples of work by different parties (Fig. 1).Fig. 1 Injection molding insert generated by stereo lithography, shown with part1. Mold ProductionIn order to discuss the main topic; the direct production of mold cavities, it is first necessary to differentiate this from the indirect route. This is not a significant topic since SL merely provides the master pattern which, irrespective of the process used to produce this, has little influence on the subsequent injection molding.1.1 Indirect Mold ProductionThe indirect methods involve the use of an initial geometry that has been produced by SL. This geometry is utilized as a pattern in a sequence of process steps that translate into a tool which may be made of a material different to that of the pattern.Cast epoxy tooling represents a common indirect plastic RT method for injection molding. The process begins with a 3D model (i.e. CAD) of the part to be molded.Subsequently this model is produced by SL to provide a master pattern around which the mold will be formed. Traditionally, the part is produced solely without provision for parting lines, gating, etc. Such ancillaries are generated by manual methods (i.e. by fixing additional features to the part). However, the advent of easier CAD manipulation allows the model to be produced including such features.Once the complete master pattern has been produced, the mold halves are created by casting epoxy around the pattern, thus recreating a negative profile of the pattern.The epoxy may include fillers in attempts to improve strength and thermal properties of the mold. Such fillers include metal and ceramic particles in various forms.1.2 Direct Mold ProductionThe direct methods involve a SL system directly generating the tooling cavityinserts in its native material. The accuracy of the SL RP process results in insertsthat require few further operations prior to their use in injection molding. Like allRP related techniques the process is dependent on a 3D CAD model of the intended geometry. Unlike indirect techniques, the whole tool insert is generated by SL and so a 3D CAD representation of the whole tool insert is required. This involves creating negatives of the part to form the mold insert bodies, plus the provisions for gating, part ejection, etc. Previously, this extra CAD work would have represented more work required in the preparation. Such input is now minimized as modern CAD manipulation packages (e.g. Materialise’s Magics software) allow the automation of such activities. Once generated, the cavity inserts need to be secured in a bolster to withstand clamping forces and to provide alignment to the mold halves.It should also be mentioned that direct SL tooling for injection molding has also been referred to as Direct AIM. This term was given to the process by 3D Systems(SL system manufacturers) and refers to Direct ACES Injection Molding. (ACES stands for “Accurate Clear Epoxy Solid,” which is a SL build style).2. The Requirement of the ProcessThe introduction of rapid prototyping has allowed engineers and designers togenerate physical models of parts very early in the design and developmentphase. However, the requirements of such prototypes have now progressed beyond the validation of geometry and onto the physical testing and proving of the parts.For such tests to be conducted, the part must be produced in the material and manner (process) that the production intent part will be. For injection molding, this situation highlights the requirement of a rapid mold-making system that can deliver these parts within time and cost boundaries.Stereo lithography provides a possible solution to this by providing the rapid creation of a mold. A negative of the part required plus gating and ejection arrangements are generated in 3D CAD to create a tool that is fabricated by SL.This provides an epoxy mold from which it is possible to produce plastic parts by injection molding.Both Luck et al. and Roberts and Ilston evaluated SL in comparison with other direct RP mold-generating techniques for producing a typical development quantity of moldings. The SLmolding process was found to be a superior alternative for producing design-intent prototypes.It has also been noted that other alternative techniques involve additional steps to the process, therefore becoming less direct and not really RT. Other advantages of the process have been highlighted beyond the prototype validation phase. Since the tool design has been verified, the lead-time and cost involved in the manufacture of production tooling is also often reduced as the tool design has already beenproven.During the early years of SL it was never envisaged that such a RT method would be possible. At first glance the application of SL for injection mold tooling seems unfeasible due to the low thermal conductivity and limited mechanical properties of epoxy, especially at high temperatures. The glass transition temperature of SL materials available was only ~60_C, while the typical temperature of an injected polymer is over 200_C. Despite these supposed limits, successful results were achieved by SL users worldwide, including the Danish Technological Institute, Ciba Geigy, Fraunhofer Institute, the Queensland Manufacturing Institute, and Xerox Corporation.3. Mold Design ConsiderationsIn terms of the mold’s actual cavity design, relatively little information exists on the specific requirements of SL tooling. The early white paper issued by 3DSystems suggests the incorporation of a generous draft angle, but does not statethe amount and recommends the use of a silicone based release agent (every shot) in an attempt to prevent the parts sticking to the inserts. Work has been conducted that quantifies the effects of draft angle on the force exerted on SL tools upon ejection of a molding. It has been shown that an increase in tooling draft angle results in a lower force required to remove a part from the tool. However, the effect of draft angle variation on ejection force is minimal and little compensation for the deviation from intended part geometry caused by the addition or removal of material required to form the draft.Work has been conducted to establish the cause of core damage during molding.This found that damage was not related to pressure, but to the size of the core features. Smaller core features were broken due to a shearing action caused by polymer melt movement.Experimentation has revealed two modes of wear during the material flow within the cavity. These modes were abrasive at medium flow points (i.e. sharp corners),and ablative at highflow points (i.e. injection points). Other work has also emphasized the importance of the material flow influenced by mold design, identifying gating, and parting line shut off areas as points of potentially high wear.Fig. 2 Parts requiring different gating arrangements according to molding material4. injectionlaser system’s degree of curing is dependent upon the pulse frequency and the hatch spacing. Generally a continuous mode laser system allows for greater energy exposure.With respect to post-curing operations it should be noted that the amount of curing is not greatly affected by UV environment exposure. If thermal post curing is tobe used it should also be noted that a large majority of warpage occurs during this stage, which may be a concern if thin walled sections are in existence.The layer thickness of each build slice dictates the SL part’s roughness on surfaces parallel to the build direction. When this surface roughness is parallel to a mo lded part’s direction of ejection it has a resultant effect on the force required to remove the part from the mold which in turn applies a force to the insert which could result in damage. This surface roughness and the ejection forces experienced,correspond linearly to the build layer thickness. The solution is to re-orientate the SL build direction or employ a lesser layer thickness.4.1 Injection MoldingDuring molding, a release agent should be frequently used to lower the force experienced by the too l due to part ejection. In the author’s experience, a siliconelike agent is the most successful. Low-injection pressures and speeds should be used whenever feasible. Much lower settings are feasible in comparison to some forms of metal tooling due to SL heat transfer characteristics as discussed within this section.Early recommendations for SL injection molding stated that since damage occurs during part ejection it was appropriate to allow as much cooling prior to mold opening as possible. This reduced the tendency of the parts to stick to the inserts . The author has trialled this approach, which often leads to greater success, but the part-to-part cycle times are extremely long.More recent work has demonstrated that it is advantageous to eject the part as soon as possible (when part strength allows) before the bulk mass of cavity features have exceeded their glass transition point, when their physical strength is greatly reduced. This greatly reduces the heat transmitted into the tool and the cycle time for each part. Subsequently, it is also critical to monitor the mold temperature throughout the molding cycle to avoid exceeding the glass transition temperature (Tg) of epoxy, where tool strength is reduced. This entails each molding cycle beginning with the epoxy insert at ambient temperature and the part being ejected prior to Tg of the majority of the inserts volume being reached. This has been achieved in practice by inserting thermocouples from the rear of the cavity insert into the most vulnerable mold features such that the probe lies shortly beneath the cavity surface. Allowing the polymer to remain for sufficient time within the mold, while also avoiding critical Tg, is possible due to the very low thermal conductivity of SL materials.In addition, the low thermal conductivity of SL materials has been demonstrated to be advantageous in this application for injection mold tooling. It has been shown that the low thermal conductivity of SL tooling allows the use of low injection speeds and temperatures which are required due to the limited mechanical properties of SL materials. Traditional metal tooling needs these high pressures and speeds to prevent the injected polymer freezing prior to the mold completely filling.This is due to the rapid cooling of the injection melt when it comes into contact with the high thermal conductivity mold surface. Also, the SL tooling process has shown itself to be capable of producing parts that would not be possible under the same conditions using a metalmold. The thermal characteristics of SL tooling have made it possible to completely mold crystalline polyether ether ketone (PEEK), which has an injection temperature of 400_C (752_F).An equivalent steel mold would require a premolding temperature of about 200_C(392_F). An impeller geometry was successfully molded with vastly lower injection speeds and pressures were utilized, as shown in the Table 1 and Fig. 3.Table 10.1 Polyether ether ketone molding variables in SL mold vs. steel moldFig. 3 PEEK impeller molded by stereo lithography toolsA particularly illustrative account of the cooling conditions is shown in the above image. It can be seen that the polymer is primarily gray in color where it contacts SL surfaces indicating crystalline formation. Whereas where it comes into contact with the steel ejector pins it is brown, indicating localized amorphous areas. This is due to the difference in heat transfer of the two materials and hence the cooling rate experienced by the contacting polymer.5. Process ConsiderationsVarious polymers have been successfully molded by SL injection molding. These include polyester, polypropylene (PP), polystyrene (PS), polyamide (PA), polycarbonate,PEEK, acrylonitrile styrene acrylate, and acrylonitrile butadiene styrene.The greatest material limitation encountered has been the use of glass filled materials. All evidence indicates that the SL molding technique does not cope well with glass filled materials due to severe problems of abrasion to the SL cavity surface. This leads to poor quality, inaccurate parts, and undercuts in the cavity, which eventually result in the destruction of the SL insert. This abrasive nature has been quantified with a comparative SL molding study of PA 66 and PA 66 with 30% glass fiber content. The PA 66 enabled 19 shots prior to damage, while the glass filled variant allowed only 6 shots before the same level of damage was incurred . These findings are supported by work conducted by the author, with PA 66 with a 30% glass fiber content inducing high mold wear. However, it has been demonstrated that appropriate choices in mold design and process variables reduced the rate of wear. The use of appropriate settings has allowed the successful molding of a low number of partsas large as 165 _ 400 _ 48 mm (6.5 _ 16 _ 2 in.) with high geometrical complexity in PA66 with 30% glass content. The tool and parts are shown in Figs. 4 and 5.6 .Molded Part PropertiesDuring the course of my work with SL tooling, I have endeavored to investigate and pursue the most important aspect of tooling and molding; it is a means to an end.The end is the molded parts themselves. These are the products and if they are unsuitable, then tool performance is entirely irrelevant. Early work examining the resultant parts produced by the SL injection process described them only as being of a poor quality, effected by warping, and requiring a longer time to solidify due to the mold’s poor heat transfer producing a nonuniform temperature distribution. Other work also noted that using diffe ring materials in a mold’s construction (i.e. a steel core and a SL cavity) led to warping of the part due to the different thermal conductivities of the mold materials .Fig. 4 Large stereolithography molding toolFig. 5 Subsequent parts produced in polyamide 66 (30% glass fiber) The low thermal conductivity, and hence the low cooling rate, of the mold has a significant influence on the material properties of the molded parts. It was shown that parts from an epoxy mold exhibit a higher strength, but a lower elongation;around 20% in both cases .The differing mechanical properties of parts produced from SL molds as compared to thosefrom metal tools is also demonstrated in other work . This showed that the parts manufactured by SL molding had a lesser value of Young’s Modulus compared to those produced in a steel mold but possessed a greater maximum tensile strength and percentage elongation at break. These different part properties were attributed to a slow rate of heat transfer of the tool. This slow rate of heat transfer produces longer part cooling times giving a greater strength but less toughness.Research performed at Georgia Institute of Technology further investigated the mechanical properties of parts produced by the SL molding process. This work showed that noncrystalline and crystalline thermoplastic parts produced by the SL molding technique displayed differing mechanical characteristics than parts from traditional molds. Noncrystalline material parts possessed similar all-round mechanical properties compared to those produced in identical steel molds. However, crystalline thermoplastic parts demonstrated higher tensile strength, higher flexural strength, and lower impact properties compared to those manufactured in identical steel molds. More so with crystalline polymers than with amorphous materials, the mechanical properties of the plastic parts are influenced by the cooling conditions. These differing effects on mechanical properties have been demonstrated with PS (amorphous) and PP (crystal line). When the respective part’s mechanical properties were compared when produced by steel and by SL molds, the PS parts showed very little change while the PP parts demonstrated a great difference . In addition to differences in mechanical properties it has also been identified that some polymers exhibit different shrinkage according to the cooling conditions of the part during molding. These works indicate that crystalline polymers are susceptible to greater shrinkage when subjected to a slow cooling time.These differences in part properties have been attributed to the degree of crystallinity developed in the molded parts. This has been demonstrated by microscopic comparisons of parts produced by SL and metal alloy tooling. This revealed the spherulites (a crystal structure consisting of a round mass of radiating crystals) to be considerably larger from the SL tooling parts due to the higher temperatures and slower cooling involved during molding.In the wider field of general injection molding and plastics research, work has been conducted to identify and assess the variables that influence parts properties. These papers report a common theme, they identify the thermal history of the part to be a critical variable responsible for the parts resulting attributes. Recent work has shown that the slower molded part cooling imposed by SL tooling provides an opportunity to make some variations in the molding parameters for crystallinepolymers which allow the control of critical morphological factors (level of crystallinity). The subsequent level of crystallinity dictates many of the resultant part properties. The process modifications in this work were realized without changes to the machine, tool, or molded material (i.e. external cooling control, different polym er etc). This demonstrates a possible “tailoring” of molded part properties that would allow certain desirable part properties to be altered.These revelations demonstrate an advantage of SL tooling that was shown to not be possible in metal tooling. In summary, we must consider that the thermal characteristics of SL molds have an influence on the morphological structure of some parts. This may lead to a difference in the morphology of parts from SL tools as compared to those from metal tools. Such morphological differences can affect the shrinkage and mechanical properties of the molded part. When using SL tooling, one must decide if these differences are critical to the functionality of the part.7. ConclusionIn conclusion, SL molding is a viable process for some, but by no means all,injection molding tooling applications. Most important, is that the user should beinformed of the alternate design and processing requirements compared to conventional tooling, and be aware of the difference in resultant part characteristics, thus enabling realistic expectations and a more assured project outcome.注射成型应用摘要在快速成型领域中塑料模具在注塑成型时的应用，它在生产过程中可以制造出小批量生产降低成本和缩短时间的注塑模具。

模具注射成型毕业论文中英文对照资料外文翻译文献

模具注射成型中英文对照资料外文翻译文献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 plasticated),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 storke; pushes unmelted 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 .Moving plate 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 moldmounting 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 .Thismember 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 whenit is holding the mold closed.They also serve as a gutde 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 storke of the moving plate.Methods of melting and injecting the plastic differ from one machine to another and are constantly being improred .couventional 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 plastcating 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 jection molding arises because the densities of polymers change so markedly withtemperature and pressure.Athigh temperatures,the density of a polymer is considerably cower than at room temperature,provided the pressure is the same.Therefore,if modls 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 machanism that serve as the tension members of clamp when it is holding the mold closed.Ejector is a provision in the claming unit that actuates a mechanism within the mold to eject themolded 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 morecavities,consists of two basic parts :(1) a stationary molds half one the side where the plastic is injected,(2)Amoving 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 moldintrior .(3)Sprue Bushing(sprue)-Provide means of entry into moldinterior .(4)Runners-Conrey molten plastic from sprue to cavities .(5)Gates-Control flow into cavities.(6)Cavity(female) and Force(male)-Contorl the size,shapeand 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 sprue 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 sprue 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 colling.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。

模具设计与制造专业外文翻译--气辅注射成型

外文原文：Gas-Assisted Injection MoldingInjection molding is a very popular operation for production of commercial plastic parts with its sophisticated control and superior surface details. However, it has limitations, such as long cycle time for parts with thick sections due to slow cooling. Also packing of thick sections can produce sink marks on the part surface. Large thin parts can have warpage because the residual stress and strain induced during filling and packing. Thus traditional injection molding can be modified to solve these kinds of problems, also to improve the quality of the part and lower the cost of production.Currently, gas-assisted injection molding is in use and being developed worldwide. In the US, the process is known as Gas-Assisted Injection Molding (GAIM); it is also called Gas Injection Technique (GIT) in Europe (see Fig.4.3.1). This process is developed for the production of hollow plastic parts with separate internal channels. It is unique because it combines the advantages of conventional injection molding and blow molding while differing from both. GAIM offers a cost effective means of producing large, smooth surfaced and rigid parts using lower clamping pressure with little or no finishing. By introducing the gas before complete filling, numerous problems such as warpage, sink marks, and high filling pressure are mostly overcome. Moreover, the process gives great benefits in terms of higher stiffness-to-weight ratio than the solid parts with the same overall dimensions due to the elimination of material placed inefficiently near the neutral axis of the cross section, thus increasing the freedom of part design.In comparison with conventional injection molding, the gas-assisted process is more critical in terms of process control, especially for multi-cavity applications. The quality of the part is determined by both tool and process variables such as degree of under-fill, gas injection conditions, and mold temperature, thus indicating the importance of process control. The process is attracting many molders due to the demand for highly automated production of gas-assisted injection molded parts.The gas-assisted injection molding process is the most rapidly growing fieldwith considerable work going on in the field of controls and the process development. Research interest is drawn towards the development of new gas injection units, the study of the process variable, the efficiency of the production process, and advantages offered by the new process. Many different companies are offering gas injection-molding units with the various options, which are mainly pressure controlled or volume controlled processes.In gas injection molding, the mold is partially filled with molten thermoplastic, and an inert gas, usually nitrogen, is injected into the plastic. Gas is injected into the molten thermoplastic material using either of two procedures. In one method, a measured volume of gas is pressurized in a container. A valve is opened to allow the gas to flow into the polymer, and a piston is activated to force all gas from the container into the mold. As the gas expands in the mold, its pressure drops. A second method holds gas pressure, rather than gas volume, constant. The gas rapidly travels down the thickest-and therefore the hottest-section of the part, advancing the melt front and filling and packing the mold. Additional plastic volume may be displaced by the pressurized gas as the material shrinks. After the plastic cools, the gas is allowed to escape, leaving a molded plastic part containing internal voids.The standard GAIM process can be divided into four partial steps. The first step is a stage of melts injection [Fig.4.3.2 (a)]. The cavity is partially filled with a defined amount of melt. The required volume is empirically determined by performing filling studies in order to avoid blowing the gas through at the flow front and to ensure an ideal blowhole volume. Typically the polymer fills thecavity between 75%~95% before the meltand gas transition.The gas inlet phase is the second stage,which is shown in Fig. 4. 3. 2(b). Gas maybe added at any point in time either duringor shortly after melts injection. The gas canenter only if the gas pressure exceeds themelt pressured. In the interior of the moldedpart, the gas expels the melt from the plasticnucleus until the remainder of the cavity iscompletely filled. Gas injection pressuresrange from 0.5~30Mpa (70~4500psi).At the gas holding pressure phase, [Fig.4.3.2(c)] the gas continues to push thepolymer melt into the extremities of thecavity of the molded article acts as a holdingpressure to compensate for path of leastresistance as it pushes through the polymer.The final stage is a gas return for recycling or a gas release to atmosphere [Fig.4. 3. 2 (d)]. After the gas holding phase, the gas pressure in the molded article is released to the outside by suitable gas return and/ or by pressure release.A. Advantages of the GAIM processGas injection provides a solution to a number of problemsthat occurs in conventional injection molding.(1) Reducing stress and warpageWith gas, the pressure is equal everywhere throughout the continuous network of hollow channels. When designed properly, these provide an internal runner system within the part, enabling the applied pressure, and therefore the internal stress gradients, to be reduced markedly. This reduces a part’s tendency to warp.(2) Elimination of sink marksSink marks resulting from ribs or bosses on the backside of a part have long been a problem. These surface marks result from the volume contraction of the melt during cooling. Sink marks can be minimized or eliminated if a hollow gas channel can be directed between the front surface of the part and the backside detail. With gas injection, the base of the rib made somewhat thicker to help direct the gas channel. With a gas channel at the base of a rib, material shrinks are away from the inside surface of the channel as the molded part cools because the material is the hottest at the center. Therefore, no sink mark occurs on the outside surface as the part shrinks during cooling.(3) Smooth surfaceUnlike structural foam, gas injection permits lighter weight and saves material ina structurally rigid part. With gas holding, a good surface quality can be achieved.(4) Reduced clamp tonnageIn conventional injection, the highest pressure occurs during the packing phase. The maximum injection pressure is significantly lower in GAIM and a controlled gas pressure through a network of hollow channels is used to fill out the mold. This means that clamp tonnage requirements can be reduced by as much as 90%.(5) Elimination of external runnersOne of the best features of gas injection is that flow runners can be built right into the part. Frequently, all external runners (both hot and cold) can be eliminated, even on a larger and complex part. These benefits include the reduced tooling costs, the lower quantities of regrind from runners, and the improvement of temperature control over the plastic melt. Often the internal runners can improve the flow pattern in the mold and eliminate or control knit-line location resulting from multiple injections from multiple injection gates. In addition to serving as flow channels, the ribs and thick sections can provide structural rigidity when required.(6)Permitting different wall thicknessA constant wall thickness is maintained in the plastic parts. With gas injection, this design rule is flexible. Different wall thicknesses are possible if gas channels are designed into the part at the transition points. This permits uniform materialflows in the mold and avoids the high stresses and warpage that normally result from this sort of geometry.(7) Cycle time ReductionCompared with structural foam, gas-injection parts do not have the same inherent insulating characteristics, so that cycle times are faster-reportedly even faster than would be conventional injection of the same part with no hollow sections.(8) Resin savingGas assist plays a direct role in part-weight saving in the conversion of current tools. The main factor in reducing weight is that the part cavity is never completely filled. Another major contributor to resin saving is scrap reduction. With proper tool design, gas assisted allows scrap-free startups and production runs.B. Disadvantages of the GAIM processAll processes have their disadvantages, but those of GAIM and GAIMIC (Gas-assisted injection molding with internal-water cooling) appear relatively minor compared with their significant advantages.(1) Large hollow sectionsGIAM is not well suited for thin-walled hollow parts such as bottles or tanks. However, the thin-wall part has also tried out for some specific applications.(2) Vent holeThe gas must be vented prior to opening the mold, leaving a hole somewhere on the part. Normally this can be placed in a non-visible location, but if appearance or function is affected or secondary operations are required, it may be necessary to seal the hole.(3) Mold temperature controlSince wall thickness along the gas flow channel is a function of cooling rate, consistent wall thickness requires precise mold temperature control.(4) Surface blushThe gas channel may leave surface blush, which arises from differences in surface gloss leaves. The tendency for blush is a function of processing conditionsand types of plastics.(5) Unique designThe unique part design and mold design required in most cases to fully utilize that GAIM might be considered by some to be a disadvantage. The gas part design takes a relatively longer time than with the conventional injection molding process.(6)Extra cost of controllerIn order to control the gas injection, the process requires extra equipment. Gas-assisted injection molding with internal cooling requires a system for controlling the gas and the water, an expense not required with traditional injection molding.C. Types of process defects in the GAIMFingering, gas bubbles, hesitation lines, burning of resin, witness line cold slug, and gas blowout are typical defects normally encountered in GAIM.Fingering, or gas permeation, is a common problem encountered in GAIM. In fingering, gas escapes from the gas channel and migrates into undesired areas of the part. Severe gas fingering can result in significant reduction n in part stiffness, impact strength and reliabitity of the final molded part. During the gas holding phase, the transitional region between the gas channel and the flat area is possible for fingers to form within the flat area. In this case, the main cause of the fingering effect is the higher its shrinkage potential, and hence the greater danger of the fingering effect. In order to largely exclude the fingering effect through design, it is necessary to implement the following criteria: a basic wall thickness of 4mm or greater should be avoided for flat areas, a material with favorable solidification behavior should be selected, and the lowest possible gas pressure should be applied.Gas bubbles are caused by fingering. When fingering occurs, gas sometimes gets trapped in the thin-wall sections of the part where the gas is unable to fully vent. These trapped gases can cause bubbles that will still be in the gas core after the mold is opened.Hesitation lines appear on the surface of a part produced by GAIM when theshort shot of resin stops in the cavity, then starts moving again as the gas completes the fill.Burning of the resin can appear on either the outer surface of the part or within the gas channel itself. Burning of the part surface can be caused by gas pressure that is too high or by insufficient venting of the mold. Burning, the resin within the hollow sections of the part is also possible. Burning within the gas channel can cause gas injection pins to become plugged.On thin-walled parts molded in certain resins, a witness line, or gloss-level change, can occur over the gas channel. Excessive gas pressure can also cause witness lines over gas channels.When gas is injected through the molding machine nozzle, cold slugs of resin may occur on the part surface. A cold slug is caused when a small amount of unmelted resin is injected into the part.Gas blowout occurs when there is not enough resin in the cavity to hold the gas inside the part. If the part is short, gas will migrate to the non-filled area of the cavity and blow through. When blowout occurs, the part will sometimes look like a short shot.Most cases of defects are produced by the interface of the gas and the melt. These problems can be overcome by internal water-cooling between the interface of the gas and the melt.中文译文：气辅注射成型注射成型是一种很普通的生产方法，用于加工那种生产时难以控制和有复杂表面的商业塑件。

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。

注射模小型抽芯机构的设计外文翻译、中英文翻译、外文文献翻译

翻译原文一：Design of Small Core DrawingMechanism for Injection MouldWu Guang ming(Dongguan Science and Technical School, of Guang Dong province Dongguan 523000)Abstract: Four kinds of small and nimble core drawing mechanism for injection mould of case type plastic items are introduced in details.Key words: injection mould, core drawing, sliding blockCase type plastic items play an important role in the production of modern plastic-electronic items. In general, knots sometimes together with a bolt are used to enhancer and smooth the surface of the electronic products. A mould often holds several work pieces, and core drawing is used many times in just one work piece. If we use traditional outside slanting pillar or inside slanting slide block in core drawing, the mechanism of the mould would be very complicated. In practice,Figure 11. moving die insert2. moving die pate3. spring4. core slide block5. fixed die insert6. fixed die plate7. lock insert block8. center pin 9. spring 10.fixed plate of moving dieaccording to the property that the stroke of core drawing of plastic items is very short, several kinds of core drawing mechanisms are designed as follows.1 Outside core drawing mechanismOutside core drawing mechanism as in Fig.1 is similar to traditional slanting pillar core drawing mechanism, Because of the short stroke of core drawing, slanting pillar is removed. Lock insert block 7 and core slide block 4 serve together to accomplish the action of reset and lock. When the mould is opened, moving die and fixed die are parted and core slide block 4 finishes core drawing under control of spring 3. Center pin 8 is used to locate the core slide block. Core slide block 4 has T guide way machined to ensure the accuracy of core drawing movement.Figure 21. moving die insert2. center pin3. core slide block4. fixed die insert5. lock insert6. fixed die plate7. spring8. moving die plate2 Inside core drawing mechanismSlanting slide block detached core drawing or drawing or slanting thimble are often used in traditional inside core drawing mechanisms. It is hard to machine.Because the distance of friction movement of slanting slide pole is long, and friction device is hidden in the middle of the mould, it is difficult to lubricate and the slanting slide pole tends to be easily worn down. Slanting slide block inside drawing mechanism in Fig.2 solves this problem well. When the dies are closed, core slide block 3 resets under the influence of lock insert 5. When the dies are opened, block 3 and lock insert 5 is parted and block 3 finishes core drawing under control of spring 7. Center pin 2 is used to locate the core slide block. The whole mechanism is dependent and easy to machine.3 Compound mechanism that core draws inside and outside at the same timeWhen a mould holds several different work-pieces and has to be core drawn inside and outside at the same time, compound core drawing mechanism illustrated in Fi.3 can be used. The picture shows the state when the dies are closed. TheFigure 31.moving die insert2.spring3. outside core insert4. fixed die insert5.fixed die plate6. lock insert7. fixed die insert8. moving die insert9.inside core insert 10. core slide block 11. center pin 12. moving die plateslants of lock insert 6 and core slide block 10 cooperate to reset and lock the core. When the dies are opened, core slide block 10 finishes inside and outside core drawingat the same time under control of spring 2. The position is limited by center pin 11. To make the core easily machined and conveniently maintained, the core can be made to be assembled. When two different cases need core drawing outside at the same time, compound mechanism in Fig.4 can be used. With the use of two slanting insert blocks, the mechanism is simplified, and the strength condition on lock insert is greatly improved.4 A simplified core drawing mechanismFor outside core drawing whole mould space is not so large, a simplified mechanism as shown in Fig.5 can be used. When the dies are closed, slanting slide block 3 oppresses spring 6 and resets under the influence of fixed die insert 1.Figure 41. moving die insert2. fixed die plate3. spring4. moving die plate5. spring6. core slide block7. fixed die insert8. fixed die plate9. lock insert 10. fixed die insert 11. core slide block12.spring 13.spring 14.moving die insertTwo guide pins 5 serve to guide. When the dies are opened, moving die insert 1 is parted from moving plate 4 and slanting slide block 3 slides up along guide pin 5 to finish core drawing under influence of spring 6. Core drawing is accomplished in one instant so that the time of opening mould is shortened and the productivityis improved. This kind of core drawing mechanism can be changed to be used for fixed mould core drawing.It has been proved by practice that core drawing mechanisms illustrated above are simple and dependent. We are easy to maintain and the production costs are greatly reduced. But in practice we must check the elasticity of springs from time to time in case they are out of use.Figure 51. fixed die insert2. moving die insert3. slanting slide block4. moving die plate5. guide pin6. spring7. blot译文一：注射模小型抽芯机构的设计吴光明东莞理工学校（广东东莞52300）摘要：介绍了外壳类塑件注射模设计生产中，行程较短抽芯的几种简单、灵巧的抽芯机构，可为类似塑件的注射模设计提供帮助。

A geometric approach for injection mould filling simulation外文文献翻译

本科毕业论文外文文献及译文文献、资料题目：A geometric approach for injectionmould filling simulation文献、资料来源：International Journal of MachineTools & Manufacture 45 (2005) 115–124文献、资料发表日期：2004.6.15院（部）：材料科学与工程学院专业：材料成型及控制工程班级：成型081姓名：刘振海学号：2008101186指导教师：徐淑波翻译日期： 2018.3.22中文译文：注塑模具充料模拟的几何方法摘要该报告研究在带有障碍物的模具粘结空腔中从注塑口开始形成物料流的几何技术。

为了解决这些障碍物所带来的问题，往往需要进行大量的计算。

这项技术基于这样的假设：物料的流动速度与被注塑的塑料零件的壁厚成正比。

物料在注塑模腔中的复杂流动模式是由四种类型的基本流动模式组合而成的，即吸收模式、折射模式、绕射模式和合并模式。

把这四种流动模式结合起来，可迅速生成物料在注塑模具中的充型模式。

在塑料产品开发过程的概念设计阶段，掌握充型模式是很有用的。

虽然所讨论的应用范围是塑料注塑，但是这项技术可应用于许多领域。

关键词：流方面；成型充填模拟；注射成型。

1、介绍成形制造操作需要塑料和聚合物的模具或模具金属、液体或工作表。

和工业同样重要的是，大部分的工具的工作，在过去的二十年中的模具是发展很大程度上，这就是说，应用到特定边界条件下关闭模拟或优化程序。

智力，在现象层面，很多已经完成流动熔体在模具型腔中的模型。

流体流动问题的解决办法是提供充足的有限元方法和数值积分计划等的各种技术。

然而，在微粒水平（如原子或分子的相互作用），有大量的当前活动。

也许是受生物技术和纳M 技术发展前景的刺激，生物学家，化学家，材料科学家和物理学家正在研究' '分子动力学与活力。

'多体问题'为表现形式，这样一个挑战已被许多杰出的科学家公认，从牛顿时期一直到现在。

注塑模具中英文对照外文翻译文献

中英文对照资料外文翻译Integrated 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 createlow-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 one thousandth 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 fundamental understanding of how the modiﬁcations to 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 opti mization. Our simulation system is veriﬁed by an experimental example.Although many materials are available for use in RP technologies, we concentrate on usingstereolithography (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 geo metry 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 iterativemethod 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. Rap id 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..。

中英文翻译模板-注射成型技术以及住塑优化经典资料

Injection mold design and the new-type injekt by shaping technologeThe 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, 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, therunner, 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. Injection Molding . Injection molding is principally used for the production of thermolplastic part ,although some progress has been made in developing a method for injection molding some thermosetting materials .The problem of injecting a melted plastic into a mold cavity from a reservoir of melted material has been extremely difficult to solve for thermosetting plastics which cure and harden under such conditions within a few minutes 。

注塑模具设计英文参考文献

注塑模具设计英文参考文献Injection molding is a widely used manufacturing process used to produce complex and precise components. The design of injection molding molds plays a crucial role in ensuring high-quality molded products. This article provides a review of the existing literature on injection molding mold design.The first key component of an injection mold is the cavity and core. The cavity is the space in which the plastic material is molded, while the core forms the internal shape of the product. The design of the cavity and core depends on the geometry and complexity of the molded part. Several strategies are used to ensure that the cavity and core align precisely, such as the use of locating rings and holes. The design of gating, venting, and runner also plays a crucial role in the mold design process. Gates are the entry points of the molten material into the mold, while the runner delivers the molten material to the cavity. The venting system ensures the escape of gases that are generated during the molding process and helps reduce defects such as air bubbles.The second critical component of injection molding mold design is the cooling system. The cooling system removes heat from the molten plastic and the mold to control the temperature of the molded product. The cooling channels are typically designed to follow the contour of the mold cavity and core and are positioned in such a way that they can cool the plastic material uniformly. Several studies have been conducted on the effect of cooling channel design on the quality of the molded part. For example, the use of conformal cooling channels, which are channels that follow the contour of the mold cavity, has been shown to reduce cycletime and improve part quality.The third critical component of injection molding mold design is the ejection system. The ejection system ejects the molded product from the mold after it has cooled and solidified. The design of the ejection system depends on the shape and geometry of the molded product, the location of the gate and runner, and the molding material. Several strategies are used to ensure that the ejection system operates smoothly, such as the use of ejector pins, the use of hydraulic ejection systems, and the use of air ejection systems.Finally, several simulation tools are used to optimize the mold design process. These tools can be used to predict the behavior of the plastic material during the injection molding process. Simulation tools can also be used to optimize the cooling system and reduce cycle time.In conclusion, injection molding mold design is a complex process that involves the design of the cavity and core, gating and venting, cooling system, and ejection system. These components must be designed to ensure that the molded product is of high quality and is produced efficiently. Several simulation tools are available to optimize the mold design process and reduce costs. The literature on injection molding mold design provides valuable insights into the design of molds for various applications.。

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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。

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。

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。

典型地，在注塑过程中模具型腔被填充至95%~98%。

然后模具成型过程将进行至压紧阶段。

当模具型腔充满的时候，熔融的塑料便开始冷却。

由于塑料冷却过程中会收缩，这增加了收缩痕、气空、尺寸不稳定性等瑕疵。

为了弥补收缩，额外的塑料就要被压入型腔。

型腔一旦被填充，作用于使物料熔化的压力就会阻止模具型腔中的熔融塑料由模具型腔浇口处回流。

压力一直作用到模具型腔浇口固化。

这个过程可以分为两步（压紧和定型），或者一步完成（定型或者第二阶段）。

在压紧过程中，熔化物通过补偿收缩的保压压力来进入型腔。

固化成型过程中，压力仅仅是为了阻止聚合物熔化物逆流。

固化成型阶段完成之后，冷却阶段便开始了。

在这个阶段中，部件在模具中停留某一规定时间。

冷却阶段的时间长短主要取决于材料特性和部件的厚度。

典型地，部件的温度必须冷却到物料的喷出温度以下。

冷却部件时，机器将熔化物塑炼以供下一个周期使用。

高聚物受剪切作用和电热丝的能量情况影响。

一旦喷射成功，塑炼过程便停止了。

这是在冷却阶段结束之前瞬间发生的。

然后模具打开，部件便生产出来了。

2.3.2注塑模具注塑模具与它们的生产出来的产品一样，在设计、精密度和尺寸方面各不相同。

热塑性模具的功能主要是把可塑性聚合物制成人们想要的形状，然后再将模制部件冷却。

模具主要由两个部件组成：（1）型腔和型芯，（2）固定型腔和型芯的底座。

模制品的尺寸和重量限制了模具型腔的数量，同时也决定了所需设备的能力。

从模具成型过程考虑，模具设计时要能安全合模、注射、脱模的作用力。

此外，浇口和流道的设计必须允许有效的流动以及模具型腔均匀填充。

图2-2举例说明了典型注射模具中的部件。

模具主要由两部分组成：固定部分（型腔固定板），熔化的聚合物被注入的旁边；在注塑设备结尾或排出旁边的瓣合（中心板）部分。

模具这两部分之间的分隔线叫做分型线。

注射材料通过一条叫做浇口的中心进料通道被转运。

浇口位于浇口轴套的上面，它逐渐缩小（锥形）是为了促进模具打开时浇注材料的释放。

在多型腔模具中，主流道将高分子聚合熔化物提供到流道系统中，流道系统通过浇口流入每个模具型腔。

中心板支撑主型芯。

主型芯的用途是确立部件的内部结构。

中心板有一个支持或支撑板。

支撑板反过来被背对注塑模顶杆空间的U型结构的柱子支撑，注塑模顶杆空间由背面的压板和垫块组成。

被固定在中心板上的U型结构，为也被叫做脱模行程的顶出行程提供了空间。

在固化的过程中，部件从主型芯周围收缩以至于当模具打开的时候，部件和浇口随着瓣合机构一起被带出来。

接着，中央的起模杆被激活，引起脱模板向前移动以至于顶杆能够推动部件离开型芯。

带有冷却通道的上下模被提供，冷却通道通过冷却水循环流通来吸收热塑性高分子聚合熔融物传递给模具的热量。

模具型腔也包含好的通风口（对于5毫米而言，通风口应该为0.02到0.08毫米）来确保填充过程中没有空气滞留在模具型腔内。

1-顶杆2-顶出板3-导套4-导柱5-下顶针板6-脱件销7-复位杆8-限位杆9-导柱10-导柱11-型腔板12-浇口套13-塑料工件14-型芯现在使用的有六种基本注射模具类型。

它们是：（1）双板模；（2）三板模；（3）热流道模具；（4）绝热保温流道模具；（5）温流道模具；和（6）重叠压塑模具。

图2-3和图2-4阐明了这六种基本注射模具类型。

1.双板模一个双板模具由每块都带有型腔和型芯的两块平板组成。

平板被固定在压板上。

瓣合机构包含工件自动拆卸机构和流道系统。

所有注射模具的基本设计都有这个思想。

双板模具是用来制作要求大型浇口制品的最合理的工具。

2.三板模这种类型的模具由三块板组成：（1）固定板或压板被连接到固定压盘上，通常包含主流道和分流道；（2）当模具打开的时候，包含分流道和浇口中间板或型腔固定板是被允许浮动的；（3）活动板或阳模板包含模制件和用来除去模制件的顶出装置。

当按压进行打开的时候，中间板和活动板一起移动，因此释放了主流道和分流道系统和清除了浇口处模制品的赘物。

当模具打开的时候，这种设计类型的模具使分离流道系统和模制件变成了可能。

这种模具设计让点浇口浇注系统能够运用。

3.热流道模具在这个注射模具的流程中，分流道要保持热的，目的是使熔融的塑料一直处于流动的状态。

实际上，这是一个“无流道”模具流程，有时候它也被叫做无流道模具。

在无流道模具中，分流道被包含在自己的板中。

热流道模具除了模塑周期中模具的分流道部分不被打开这点外，其他地方与三板注射模具相似。

加热流道板与剩下的冷却部分的模具是绝缘的。

分流道中除了热加板，模具中剩余部分是一个标准的两板模具。

无流道模具相比传统的浇口流道模具有几个优点。

无流道模具没有模具副产品（浇口，分流道，主流道）被处理或者再利用，也没有浇口与制件的分离。

周期仅仅要求制件被冷却和从模具中脱离。

在这个系统中，从注射料筒到模具型腔，温度能够达到统一。

4.绝热保温流道模具绝热流道模具是热流道模具的一种演变。

在这种类型的模具中，分流道材料的外表面充当了绝缘体来让熔融材料通过。

在隔热的模具中，通过保留自己的温度使模具中的物料一直是熔化的。

有时候，一个分料梭和热探测器被加入模具中来增加柔韧性。

这种类型的模具对于多孔中心浇口的制件来说是理想的。

5.温流道模具它是热流道模具的一种演变。

在这种模具中，流道而不是流道板被加热。

这是通过电子芯片嵌入探测器实现的。

6.重叠压塑模具重叠压塑注射模具顾名思义。

一个多重两板模具其中的一块板被放在另一块板的上面。

这种结构也可以用在三板模具和热流道模具上。

两板重叠结构使单一的挤压输出量加倍，与一个型腔数量相同的两板模具相比，还减少了一半的合模压力。

这种方式也被叫做“双层模塑”。

2.3.3压膜机1.传统的注塑机在这个流程中，塑料颗粒或粉末被倒入一个机器料斗中，然后被送入加热料筒室。

一个活塞压缩物料，迫使物料渐进地通过加热料筒中物料被分料梭慢慢散开的加热区域。

分料梭被安装在料筒的中心，目的是加速塑料体中心的加热。

分料梭也有可能被加热，以便塑料能够内外一起被加热。

物料从加热料斗流经喷嘴进入模具。

喷嘴是料斗和模具之间的密封装置它被用来阻止因为剩余压力而引起的物料泄露。

模具在注塑机的末端被夹具夹紧闭合。

对于聚苯乙烯而言，机器末端两三吨的压力通常用在之间和流道系统中每个小的投影面积上。

传统的活塞式机器是唯一能生产斑点部分的类型的机器。

另一种类型的注塑机将塑料材料充分地混合，以至于仅有一种颜色被生产出来。

2.柱塞式预塑机这种机器使用了分料梭活塞加热器来预塑塑料颗粒。

塑料颗粒变成熔化状态之后，液态的塑料被倒入一个蓄料室，直到塑料准备好被压入模具。

这种类型的机器比传统的机器生产零件的速度更快，因为在制件冷却的时间中，模具腔被填满进行喷射。

由于注射活塞在流动的物料中工作，因此在压缩颗粒的时候没有压力损失。

这种现象能够应用在带有更多投影面积的大型制件上。

柱塞式预塑机的其他特点与传统的单一活塞式注塑机是一样的。

图2-5举例说明了柱塞式预塑机。

3.螺杆式预塑机在这种注塑机中，用挤压机来塑化塑料物料。

旋转的螺杆使塑料芯块向前，提供给挤压机料筒的加热内壁。

熔融的，塑化的物料从挤压机移动到一个蓄料室，然后通过注射活塞移动到模具中。

螺杆的应用有以下优势：（1）便于物料更好的混合及塑料溶化后的剪切作用；（2）流动物料硬度的范围更广及热敏材料可以流动；（3）能在更短的时间内进行色泽改变；（4）模具制件中的应力更小4.往复式螺杆注塑机这种类型的注塑机使用了一个水平的挤压机来代替加热室。

螺杆的旋转使塑料物料向前移动通过挤压机料筒。

随着物料流经带螺杆的加热料筒，物料从颗粒状态变为塑料熔融状态。

螺杆往复的过程中，传递给模制物料的热量是由螺杆和挤压机的料筒壁之间的摩擦和传导引起的。

当物料向前移动的时候，螺杆返回到在挤压机料筒前方决定物料容量的行程开关处。

在这个时候，与典型挤压机类似的挤压过程结束了。

当物料注射到模具中，螺杆向前移动来转移料筒中的物料。

在这个注塑机中，螺杆既充当活塞，又充当螺杆。

模具中的浇口截面冻结阻止回流之后，螺杆开始旋转并且向后移动，进行下一个周期。

图2-5展示了往复式螺杆注塑机。

这种形式的注塑有几个优点。

它更有效地塑化热敏感材料，由于螺杆的混合作用更快地混合色泽。

给材料加热的文都能够更低，并且整个周期时间可以更短。

第一篇英文原文2.3 Injection Molds2.3.1 Injection MoldingInjection molding is principally used for the production of thermoplastic parts, and it is also one of the oldest. Currently injection-molding accounts for 30% of all plastics resin consumption. Typical injection-molded products are cups, containers, housings, tool handles, knobs, electrical and communication components (such as telephone receivers), toys, and plumbing fittings.Polymer melts have very high viscosities due to their high molecular weights; they cannot be poured directly into a mold under gravity flow as metals can, but must be forced into the mold under high pressure. Therefore while the mechanical properties of a metal casting are predominantly determined by the rate of heat transfer from the mold walls, which determines the grain size and grain orientation in the final casting, in injection molding the high pressure during the injection of the melt produces shear forces that are the primary cause of the final molecular orientation in the material. The mechanical properties of the finished product are therefore affected by both the injection conditions and the cooling conditions within the mold.Injection molding has been applied to thermoplastics and thermosets, foamed parts, and has been modified to yield the reaction injection molding (RIM) process, in which the two components of a thermosetting resin system are simultaneously injected and polymerize rapidly within the mold. Most injection molding is however performed on thermoplastics, and the discussion that follows concentrates on such moldings.A typical injection molding cycle or sequence consists of five phases (see Fig. 2-1):(1) Injection or mold filling;(2) Packing or compression;(3) Holding;(4) Cooling;(5) Part ejection.Fig. 2-1 Injection molding processPlastic pellets (or powder) are loaded into the feed hopper and through an opening in the injection cylinder where they are carried forward by the rotating screw. The rotation of the screw forces the pellets under high pressure against the heated walls of the cylinder causing them to melt. Heating temperatures range from 265 to 500 °F. As the pressure builds up, the rotating screw isforced backward until enough plastic has accumulated to make the shot. The injection ram (or screw) forces molten plastic from the barrel, through the nozzle, sprue and runner system, and finally into the mold cavities. During injection, the mold cavity is filled volumetrically. When the plastic contacts the cold mold surfaces, it solidifies (freezes) rapidly to produce the skin layer. Since the core remains in the molten state, plastic flows through the core to complete mold filling. Typically, the cavity is filled to 95%~98% during injection.Then the molding process is switched over to the packing phase. Even as the cavity is filled, the molten plastic begins to cool. Since the cooling plastic contracts or shrinks, it gives rise to defects such as sink marks, voids, and dimensional instabilities. To compensate for shrinkage, addition plastic is forced into the cavity. Once the cavity is packed, pressure applied to the melt prevents molten plastic inside the cavity from back flowing out through the gate. The pressure must be applied until the gate solidifies. The process can be divided into two steps (packing and holding) or may be encompassed in one step (holding or second stage). During packing, melt forced into the cavity by the packing pressure compensates for shrinkage. With holding, the pressure merely prevents back flow of the polymer melt.After the holding stage is completed, the cooling phase starts. During cooling, the part is held in the mold for specified period. The duration of the cooling phase depends primarily on the material properties and the part thickness. Typically, the part temperature must cool below the material‟s ejection temperature.While cooling the part, the machine plasticates melt for the next cycle. The polymer is subjected to shearing action as well as the condition of the energy from the heater bands. Once the shot is made, plastication ceases. This should occur immediately before the end of the cooling phase. Then the mold opens and the part is ejected.2.3.2 Injection MoldsMolds for injection molding are as varied in design, degree of complexity, and size as are the parts produced from them. The functions of a mold for thermoplastics are basically to impart the desired shape to the plasticized polymer and then to cool the molded part.A mold is made up of two sets of components: (1) the cavities and cores, and (2) the base in which the cavities and cores are mounted. The size and weight of the molded parts limit the number of cavities in the mold and also determine the equipment capacity required. From consideration of the molding process, a mold has to be designed to safely absorb the forces of clamping, injection, and ejection. Also, the design of the gates and runners must allow for efficient flow and uniform filling of the mold cavities.Fig.2-2 illustrates the parts in a typical injection mold. The mold basically consists of two parts: a stationary half (cavity plate), on the side where molten polymer is injected, and a moving half (core plate) on the closing or ejector side of the injection molding equipment. The separating line between the two mold halves is called the parting line. The injected material is transferred through a central feed channel, called the sprue. The sprue is located on the sprue bushing and is tapered to facilitate release of the sprue material from the mold during mold opening. In multicavity molds, the sprue feeds the polymer melt to a runner system, which leads into each mold cavity through a gate.The core plate holds the main core. The purpose of the main core is to establish the inside configuration of the part. The core plate has a backup or support plate. The support plate in turn is supported by pillars against the U-shaped structure known as the ejector housing, which consists ofthe rear clamping plate and spacer blocks. This U-shaped structure, which is bolted to the core plate, provides the space for the ejection stroke also known as the stripper stroke. During solidification the part shrinks around the main core so that when the mold opens, part and sprue are carried along with the moving mold half. Subsequently, the central ejector is activated, causing the ejector plates to move forward so that the ejector pins can push the part off the core. Both mold halves are provided with cooling channels through which cooled water is circulated to absorb the heat delivered to the mold by the hot thermoplastic polymer melt. The mold cavities also incorporate fine vents (0.02 to 0.08 mm by 5 mm) to ensure that no air is trapped during filling.Fig. 2-2 Injection mold1-ejector pin 2-ejector plate 3-guide bush 4-guide pillar 5-ejector base plate6-sprue puller pin 7-push-back pin 8-limit pin 9-guide pillar 10-guide pillar 11-cavity plate12-sprue bushing 13-plastic workpiece 14-coreThere are six basic types of injection molds in use today. They are: (1) two-plate mold; (2) three-plate mold, (3) hot-runner mold; (4) insulated hot-runner mold; (5) hot-manifold mold; and (6) stacked mold. Fig. 2-3 and Fig. 2-4 illustrate these six basic types of injection molds.Fig. 2-3 This illustrates three of the six basic types of injection molding dies(1) Two-plate injection mold (2) Three-plate injection mold (3) Hot-runner mold See Fig. 2-4 for theother three types.Fig. 2-4 This illustrates three of the six basic types of injection molding dies(1) Insulated runner injection mold (2) Hot manifold injection mold (3) Stacked injection mold See Fig. 2-3 for the other three types.1. Two-Plate MoldA two-plate mold consists of two plates with the cavity and cores mounted in either plate. The plates are fastened to the press platens. The moving half of the mold usually contains the ejector mechanism and the runner system. All basic designs for injection molds have this design concept. A two-plate mold is the most logical type of tool to use for parts that require large gates.2. Three-Plate MoldThis type of mold is made up of three plates: (1) the stationary or runner plate is attached to the stationary platen, and usually contains the sprue and half of the runner; (2) the middle plate or cavity plate, which contains half of the runner and gate, is allowed to float when the mold is open; and (3) the movable plate or force plate contains the molded part and the ejector system for the removal of the molded part. When the press starts to open, the middle plate and the movable plate move together, thus releasing the sprue and runner system and degating the molded part. This type of mold design makes it possible to segregate the runner system and the part when the mold opens. The die design makes it possible to use center-pin-point gating.3. Hot-Runner MoldIn this process of injection molding, the runners are kept hot in order to keep the molten plastic in a fluid state at all times. In effect this is a …runnerless‟ molding process and is sometimes called the same. In runnerless molds, the runner is contained in a plate of its own. Hot runner molds are similar to three-plate injection molds, except that the runner section of the mold is not opened during the molding cycle. The heated runner plate is insulated from the rest of the cooled mold. Other than the heated plate for the runner, the remainder of the mold is a standard two-plate die.Runnerless molding has several advantages over conventional sprue runner-type molding. There are no molded side products (gates, runners, or sprues) to be disposed of or reused, and there is no separating of the gate from the part. The cycle time is only as long as is required for the molded part to be cooled and ejected from the mold. In this system, a uniform melt temperature can be attained from the injection cylinder to the mold cavities.4. Insulated Hot-Runner MoldThis is a variation of the hot-runner mold. In this type of molding, the outer surface of the material in the runner acts like an insulator for the melten material to pass through. In the insulated mold, the molding material remains molten by retaining its own heat. Sometimes a torpedo and a hot probe are added for more flexibility. This type of mold is ideal for multicavity center-gated parts.5. Hot-ManifoldThis is a variation of the hot-runner mold. In the hot-manifold die, the runner and not the runner plate is heated. This is done by using an electric-cartridge-insert probe.6. Stacked MoldThe stacked injection mold is just what the name implies. A multiple two-plate mold is placed one on top of the other. This construction can also be used with three-plate molds and hot-runner molds. A stacked two-mold construction doubles the output from a single press and reduces the clamping pressure required to one half, as compared to a mold of the same number of cavities in a two-plate mold. This method is sometimes called “two-level molding”.2.3.3 Mold Machine1. Conventional Injection-Molding MachineIn this process, the plastic granules or pellets are poured into a machine hopper and fed into the chamber of the heating cylinder. A plunger then compresses the material, forcing it through progressively hotter zones of the heating cylinder, where it is spread thin by a torpedo. The torpedo is installed in the center of the cylinder in order to accelerate the heating of the center of the plastic mass. The torpedo may also be heated so that the plastic is heated from the inside as well as from the outside.The material flows from the heating cylinder through a nozzle into the mold. The nozzle is the seal between the cylinder and the mold; it is used to prevent leaking of material caused by the pressure used. The mold is held shut by the clamp end of the machine. For polystyrene, two to three tons of pressure on the clamp end of the machine is generally used for each inch of projected area of the part and runner system. The conventional plunger machine is the only type of machine that can produce a mottle-colored part. The other types of injection machines mix the plastic material so thoroughly that only one color will be produced.2. Piston-Type Preplastifying MachineThis machine employs a torpedo ram heater to preplastify the plastic granules. After the melt stage, the fluid plastic is pushed into a holding chamber until it is ready to be forced into the die. This type of machine produces pieces faster than a conventional machine, because the molding chamber is filled to shot capacity during the cooling time of the part. Due to the fact that the injection plunger is acting on fluid material, no pressure loss is encountered in compacting the granules. This allows for larger parts with more projected area. The remaining features of apiston-type preplastifying machine are identical to the conventional single-plunger injection machine. Fig. 2-5 illustrates a piston or plunger preplastifying injection molding machine.Fig. 2-5 The four basic types of injection molding equipment3. Screw-Type Preplastifying MachineIn this injection-molding machine, an extruder is used to plasticize the plastic material. The turning screw feeds the pellets forward to the heated interior surface of the extruder barrel. The molten, plasticized material moves from the extruder into a holding chamber, and from there is forced into the die by the injection plunger. The use of a screw gives the following advantages: (1) better mixing and shear action of the plastic melt; (2) a broader range of stiffer flow and heatsensitive materials can be run; (3) color changes can be handled in a shorter time, and (4) fewer stresses are obtained in the molded part.4. Reciprocating-Screw Injection MachineThis type of injection molding machine employs a horizontal extruder in place of the heating chamber. The plastic material is moved forward through the extruder barrel by the rotation of a screw. As the material progresses through the heated barrel with the screw, it is changing from the granular condition to the plastic molten state. In the reciprocating screw, the heat delivered to the molding compound is caused by both friction and conduction between the screw and the walls of the barrel of the extruder. As the material moves forward, the screw backs up to a limit switch that determines the volume of material in the front of the extruder barrel. It is at this point that the re- semblance to a typical extruder ends. On the injection of the material into the die, the screw moves forward to displace the material in the barrel. In this machine, the screw performs as a ram as well as a screw. After the gate sections in the mold have frozen to prevent backflow, the screw begins to rotate and moves backward for the next cycle. Fig.2-5 shows a reciprocating-screw injection machine.There are several advantages to this method of injection molding. It more efficiently plasticizes the heat-sensitive materials and blends colors more rapidly, due to the mixing action of the screw. The material heat is usually lower and the overall cycle time is shorter.第二篇译文环保意识的设计和制造ECD＆M研究的问题包括：产品与过程集成与材料选择系统的设计，评估消费者的需求和产品使用的集成模型的发展，处理或回收，改进的方法，工具和对环境危害和成本或效益的风险评估程序，在加工或最终产品的材料，降低对环境的影响替代，在预测特定的政府法规的影响在整个产品生命周期技术的进步，新的或改进的制造过程，和增加的寿命，可以减少环境影响制造新的散装材料和涂料的研制1 能源，材料和资源的关注关于在ECD＆M方法和技术的发展，在过去的十年里有了巨大的增长的研究。