模具毕业设计论文外文翻译

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本科毕业论文外文翻译【范本模板】

本科毕业论文外文翻译外文译文题目:不确定条件下生产线平衡：鲁棒优化模型和最优解解法学院：机械自动化专业：工业工程学号: 201003166045学生姓名: 宋倩指导教师：潘莉日期: 二○一四年五月Assembly line balancing under uncertainty: Robust optimization modelsand exact solution methodÖncü Hazır , Alexandre DolguiComputers ＆Industrial Engineering，2013,65：261–267不确定条件下生产线平衡：鲁棒优化模型和最优解解法安库·汉泽，亚历山大·多桂计算机与工业工程，2013，65：261–267摘要这项研究涉及在不确定条件下的生产线平衡，并提出两个鲁棒优化模型。

假设了不确定性区间运行的时间。

该方法提出了生成线设计方法,使其免受混乱的破坏。

基于分解的算法开发出来并与增强策略结合起来解决大规模优化实例.该算法的效率已被测试,实验结果也已经发表。

本文的理论贡献在于文中提出的模型和基于分解的精确算法的开发.另外，基于我们的算法设计出的基于不确定性整合的生产线的产出率会更高，因此也更具有实际意义。

此外,这是一个在装配线平衡问题上的开创性工作,并应该作为一个决策支持系统的基础。

关键字：装配线平衡；不确定性; 鲁棒优化；组合优化；精确算法1.简介装配线就是包括一系列在车间中进行连续操作的生产系统。

零部件依次向下移动直到完工。

它们通常被使用在高效地生产大量地标准件的工业行业之中。

在这方面，建模和解决生产线平衡问题也鉴于工业对于效率的追求变得日益重要。

生产线平衡处理的是分配作业到工作站来优化一些预定义的目标函数。

那些定义操作顺序的优先关系都是要被考虑的,同时也要对能力或基于成本的目标函数进行优化。

就生产（绍尔，1999）产品型号的数量来说，装配线可分为三类：单一模型（SALBP）,混合模型(MALBP）和多模式（MMALBP）。

材料成型及控制工程专业毕业设计(论文)外文翻译

中文2500字本科毕业设计翻译学生姓名：*****班级：*****班学号：*****学院：材料科学与工程学院专业：材料成型及控制工程指导教师：***** 副教授2011年3月25日Section 4 – Die Design and Construction Guidelines for HSS Dies General Guidelines for Die Design and ConstructionDraw DiesHigher than normal binder pressure and press tonnage is necessary with H.S.S. in order to maintain process control and to minimize buckles on the binder. Dies must be designed for proper press type and size. In some cases, a double action press or hydraulic press cushion may be required toachieve the necessary binder forces and control. Air cushions or nitrogen cylinders may not provide the required force for setting of draw beads or maintaining binder closure if H.S.S. is of higher strength or thickness.Draw beads for H.S.S. should not extend around corners of the draw die. This will result in locking out the metal flow and cause splitting in corners of stamping. D raw beads should “run out” at the tangent of the corner radius to minimize metal compression in corners, as shown in figure 16 on page 47. Better grades of die material may be necessary depending on the characteristics of the HSS, the severity of the part geometry, and the production volume. A draw die surface treatment, such as chrome plating, may be recommended for outer panel applications.Form and Flange DiesPart setup in form and flange dies must allow for proper overbend on all flanges for springback compensation. Springback allowance must be increased as material strength increases; 3 degrees for mild steels, but 6 degrees or morefor HSS.Punch radii must be fairly sharp. 1t for lower strength steels. Higher strength steels may require larger radii, but keeping them as small as practical will reduce springback in the sidewalls.Flange steel die clearance must be held to no more than one metal thickness clearance to reduce springback and sidewall curl.Form and flange steels should be keyed or pocketed in the casting to avoid flexing.Flange steels should be designed to wrap over and coin the flange break in order to set the break and reduce springback. See figure 17 on page 48.Die strength must not be compromised with light-weight die construction. High strength steel will require a stiffer die to resist flexing and the resultant part distortions, especially for channel or “hat-section” parts. This type of part can also cause serious die damage if double blanks occur.Cutting DiesTo reduce press tonnage requirements and extend die life, a minimum shear of four to six times metal thickness in twelve inches of trim steel length is recommended.To reduce die maintenance, maximum trim angles should be about 5° to 10°less than those used for mild steel. Trim steels should be keyed or pocketed in casting to avoid flexing. Die clearance should be 7 to 10% of metal thickness.Drawbead TypesConventional Drawbeads Run-out Drawbeads For H.S.S.Lock Beads for Stretch-Form DieFigure 161. Providing a vertical step in the flange stiffens and straightens the flange, stopping sidewall curl as well as springback.2. The addition of stiffening darts helps maintain a 90-degree flange.3. By adding a horizontal step along the flange, the flange is stiffened, resulting in reduced springback.4. Back relief on the upper flange steel allows for extra pressure to be applied futher out on the formed radius.Section 5 – Die Tryout Guidelines for High Strength Steel DiesGeneral Guidelines for Die TryoutDraw DiesHigher draw die binder pressure and press tonnage will be necessary in order to maintain process control and draw parts without buckles. A double action press or a press with hydraulic cushion may be required in some cases to achieve the required binder forces.HSS draw die operations will require sheet steel lubricants that are formulated for extreme pressures. Mill oils will not provide sufficient lubricity for most applications. Pre-lubes or dry film lubricants may be necessary for process control.Die plan view punchline corner radii should be larger than with mild steels to avoid buckling in the corners of the binder.Stretch Form DiesLock beads may require modification to avoid cracking or tearing with higher strength grades of HSS. Opening side walls of beads and enlarging corner radii will avoid cracking of high strength sheet steel. Lock beads should be continuous around the punchline for stretch form dies.For large panels from stretch-form dies, such as a roof panel or hood outer, elastic recovery may result in a shrunken panel that does not fit well on the male die member of the trim or flange dies. This problem is corrected by adding a “plus” factor to the overall part dimensions of the draw die or stretc hform die punch. This “plus” is usually no more than 2.5 mm at the center of the sides and the front, tapering to 0.0mm at the corners of the part profile on the punch. Finish part profile is defined, and plus is removed, in the main flange die.Form and Flange DiesThe punch radius should be fairly sharp with 1 or 2t used for lower strength steel. HSS may require larger radii, but as small as practical to reduce springback of sidewalls.The flange steel radius affects sidewall curl and springback on any offset flanges. This radius should also be small to reduce springback of side flanges. Overbend for springback compensation must be increased as tensile strength increases: 3 degrees is standard for mild steels, but 6 degrees or more will be required for HSS.Flange steel die clearance should be tight, maintaining no more than one metal thickness clearance to reduce springback and sidewall curl.Cutting DiesTo reduce press tonnage requirements and extend die life, a minimum shear of four to six times metal thickness in twelve inches of trim steel length is required.Die clearance should be 7 to 10% of metal thickness for HSS.To reduce trim steel maintenance, reduce maximum trim angles by about 5° to 10° from those used for mild steel. Trim steels should be keyed or pocketed in the casting to avoid flexing.Die Tryout When Using Bake Hardenable SteelIn order to obtain the maximum benefits of BHS, tryout of the dies should be performed as follows: Circle grid analysis must be performed on a panel before any die rework is attempted. With the gridded panel as a reference, the die can be modified to provide a minimum biaxial stretch of 2.0%. Stretch-form or draw dies are best for this material.For rough or functional tryout, it is possible to use mild steel with a 6% to 8% gauge increase to perform the normal process of die preparation. This alleviates complications when the BHS strengthens between each die being tried out. The reason for this is the time lag that normally occurs between a panel being formed and its use in the next operation.When the entire line of dies is ready for approval, all dies must be set in line. Panels should be run through all the die operations consecutively. This will avoid some of the strengthening effects of time delays between stamping operations that can cause variation in panels. Dimensional approval of the panel will be most difficult if this procedure is not followed.The strengthening reaction in the BHS can cause dimensional variation in flanges since springback will vary with time as the strength increases. This is why running the panel through all die operations consecutively is crucial to a successful buyoff.Part BuyoffTo reduce the part buyoff time and eliminate many hours of tryout time, the benefits of functional build must be considered. This procedure has beenproven to save time and money by concentrating on an acceptable sub-assembly rather than making each stamping to part specifications. Those parts that are easiest to change are revised to suit the sub-assembly dimensional targets. Those parts that do not affect the sub-assembly quality are not changed, but the detail part specifications are revised. The functional build process will eliminate excessive tryout hours if used for part buyoff on HSS stampings.In addition to saving tryout time and die rework costs with functional build, lower part variation can also be realized. Two dimensional challenges faced by the die maker when first trying out dies are to reduce the dimensional variation from nominal specifications, and to reduce the short term variationfrom part to part. The typical priority is to first minimize part-to-part variation and later address nominal deviation. A strong argument for this strategy is that the deviation from nominal is not precisely known until a dimensionally consistent part can be evaluated. The results are a dimensionally consistent part even though a number of checkpoints may deviate from nominal, and perhaps even be out of tolerance. In many situations when dimensions on the die are reworked to shift them closer to nominal, they become less stable and result in higher part-to-part variation. The functional build philosophy evaluates the acceptability of the part after it becomes stable, and before minor dimensional shifts are made. Large deviant or critical dimensions may be identified for rework even with functional build. There are dimensions that can often be spared rework based on a functional build approach. In these cases, the part remains more stable and the die more robust because less rework occurs while attempting to shift dimensions.For more information on functional build, refer to the Auto/Steel Partnership publication. “Event-Based Functional Build: An Integrated Approach to Body Development”.第四节-高强度钢模具设计和制造指南对模具设计和制造的一般准则拉深模具为了控制高强度钢的成形并减少板料边缘的弯曲，高强度钢成型时的压力和吨位高于一般情况是必要的。

本科毕业设计外文翻译(中文)

本科生毕业设计（论文）外文翻译外文原文题目：Real-time interactive optical micromanipulation of a mixture of high- and low-index particles中文翻译题目：高低折射率微粒混合物的实时交互式光学微操作毕业设计（论文）题目：阵列光镊软件控制系统设计姓名：任有健学院：生命学院班级：06210501指导教师：李勤高低折射率微粒混合物的实时交互式光学微操作Peter John Rodrigo Vincent Ricardo Daria Jesper Glückstad丹麦罗斯基勒DK-4000号，Risø国家实验室光学和等离子研究系jesper.gluckstad@risoe.dkhttp://www.risoe.dk/ofd/competence/ppo.htm摘要：本文论证一种对于胶体的实时交互式光学微操作的方法，胶体中包含两种折射率的微粒，与悬浮介质（0n ）相比，分别低于（0L n n <）、高于（0H n n >）悬浮介质的折射率。

球形的高低折射率微粒在横平板上被一批捕获激光束生成的约束光势能捕获，捕获激光束的横剖面可以分为“礼帽形”和“圆环形”两种光强剖面。

这种应用方法在光学捕获的空间分布和个体几何学方面提供了广泛的可重构性。

我们以实验为基础证实了同时捕获又独立操作悬浮于水（0 1.33n =）中不同尺寸的球形碳酸钠微壳（ 1.2L n ≈）和聚苯乙烯微珠（ 1.57H n =）的独特性质。

1 引言光带有动量和角动量。

伴随于光与物质相互作用的动量转移为我们提供了在介观量级捕获和操作微粒的方法。

过去数十年中的巨大发展已经导致了在生物和物理领域常规光学捕获的各种应用以及下一代光学微操作体系的出现[1-5]。

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。

文献翻译-注塑模具的设计与热分析

编号：毕业设计（论文）外文翻译（译文）学院：国防生学院专业：机械设计制造及其自动化学生姓名：学号：指导教师单位：姓名：职称：2014年1月10日注塑模具的设计与热分析摘要:本文介绍了用于生产热变形测试样品的注塑模具的设计，这种模具能为自身实现热分析，从而得到模具的热残余应力的影响。

文章对技术，理论，方法以及在注塑模型设计中需要的考虑的因素也进行了介绍。

模具设计是通过商用计算机辅助设计软件Unigraphics系统的13.0版本实现的。

这种用于分析因样品不均匀冷却产生的热残余应力的模具，已经通过使用13.5版的被称作LUSAS分析员的商业有限元分析软件得到了开发，而且存在问题也已经解决。

该软件通过绘制相应的时间反应曲线为模具提供了温度分布等高线图以及注塑周期中的温度的变化。

结果表明，与其他区域相比，收缩可能更容易发生在冷却渠道附近的区域。

热变形就是这种在模具的不同区域的不均衡降温效果引起的。

关键词：注塑模具；设计；热分析1. 引言塑料业是世界上发展最快的工业之一，被列入产值达数十亿美元的产业。

几乎每一个在日常生活中使用的产品都涉及塑料的使用，这些产品大部分可通过注塑成型方法生产［1］。

注塑成型工艺因其制造过程是以较低的成本生产各种形态和复杂几何形状的产品而众所周知［2］。

注塑成型工艺是一个循环工艺，整个过程分为四个重要的阶段，即：充模，保压，冷却和喷射。

在注塑成型过程是从漏斗中把树脂和适当的添加剂注入到注塑成型机的加热/注射系统开始的［3］。

这就是“充模阶段”，在这个过程中，模腔填充了达到注射温度的热聚合物熔体。

在模腔填充后的“保压”阶段，更多的是聚合物熔体在更高的压力下被装进腔体，以补偿因聚合物固化引起的预计萎缩。

接下来便是冷却阶段，在此过程中模具会冷却，直到有足够的刚性部分被弹出。

最后一个阶段是“弹射阶段”，这个阶段模具被打开，成型部分被弹出，过后，模具会再次被关闭开始下一个循环［4］。

因为主要是靠经验，包括了实际工具的反复修改，所以设计和制造所需性能的注塑成型聚合物部件的过程很昂贵的。

机械毕业设计英文外文翻译471塑料模具CAD集成技术

附录1 英文原文The molding tool CAD gathers the techniqueContents brief summary: Pass to analyze the calculator the assistance inject the mold design with make in the each link commonly shared of technique with information, this text announces to public to inject the mold CAD gathers technical and basic content, and the research heat that put forward it orders with trend.0, prefaceThe molding tool CAD gathers the technique is an important molding tool forerunner manufacturing technique, is the item reforms with the high technique traditional technical and important key in molding tool technique. From 6 5 plan beginning,Our country contain many molding tools business enterprise adoption CAD technique, especially recent years, the technical application in CAD is more and more widespread with thorough, shortened consumedly molding tool design period, Increases to make the mold quantity with the manufacturing ability that complicated molding tool.However, gather to the molding tool CAD because of many business enterprises technique cognition shortage, investment take the blindness, can't produce result nicely,Result in very big and wasted.This text gathers for the plastics molding tool CAD technique and its applications announce some standpoint, provide everybody consults.1, the plastics molding tool CAD gathers techniqueThe manufacturing of the plastics molding tool comtains the construction design of the shape design, molding tool and the number of the analysis, molding tools that include the plastics products control to process( I I , electricity process, the line incises etc.), throw the light with go together with to try the mold and take shape manufacturing etc. quickly.The each link a CAD for involving unit technique has: The shape design( CAD) with the construction, fast anti of the product shapebeg( RE), construction analysis with excellent turn the design( CAE), lend support to the manufacturing( CAM) and process the process conjecture imitate true( SIMULATION), product and molding tools take shape( RP) quickly, assistance craft process( CAPP) with product data management technique( PDM) etc..The plastics molding tool CAD gathers technique,Is to gather plastics molding tool manufacturing process a various units for involving technique get up, unify the database to deliver the format with the document, realize the information gather share with the data resources, from but shorten the design manufacturing period of the molding tool consumedly,Increases to make the mold quantity.2, the CAD design of the plastics product begs with fast anti of the shapeThe plastics molding tool that proceed the square one designs the manufacturing is the design of the EU a product.The traditional product design method is a design to product of three is conceive outline to use two I plane chart papers expresses to come out, marking clearly the craft and starting construction the method on the diagram paper,This kind of met hod comes to a decision the simple of a design sketch and can''ts control to make the quantity directly.The modern design method is a design establish the product directly on the computer of three the model of I ,According to the product three I models proceed the molding tool construction the design and excellent turn the design,Design according to the molding tool construction again three I models proceed to process to weave the distance and establishment crafts plan.This kind of method makes product model design, molding tool construction design, process to weave distance and technological designs regard a data as the foundation, realizing the data share, Can not only increases to design the efficiency quickly, but also can guarantee the quantity, decline low cost.The source of the computer EU a product model has three kinds of:Making use of the CAD system software proceeds the product model the designand make use of the real object measures fast anti in proceeding beg to set up the mold and make use of the standard format document of the other the system of CAD.Source method that aim at these three kinds of products model,Have studied every kind of technique now to the design efficiency that increases product model with quantity.The underneath further analyzes every kind of technical content with the characteristics.Making use of the CAD system software proceeds the product model design,Its technique includes primarily two is are several why the sketch draws, two the parameter of is turn the design of the sketch, three i entity shape design, three icharacteristic shape design, three the parameter of is turn the entity shape the design, three i curved face shape design, free shape in space design, the external appearance of the product exaggerates, product of dynamic advertise to design the etc..These softwareses contain many typical representatives.Two the software of is have: ME10, CADKEY, AUTOCAD, DHCAD, Genis, etc. of Sigraph; three the software of is have:UGII, PRO/ E, IDEAS, CATIA, etc. of EUCLID; free shape in product and advertise the software of the design have:Alias, etc. of CDRS.Two is are several why the sketch draws is to make use of the flat surface CAD software draw the spare parts sketch, then replace the handicraft painting with the calculator; but two the parameter of is turn,Then the calculator realizes the sketch changes the deal designs, making modification more convenient; threeishape designs is a true shape that the product that the arithmetic figure turn design, it expressed completely product,Can be further to designs for the molding tool, analysis with processes the mathematics model of the necessity of offering; the free shape in space design is the art of the product shape to design, making product been not only is a function product, but also art article.It is every kind of need that the external appearance of the product exaggerate that product of the result designs, making product more beautiful, the color can attractpeople more; the dynamic advertisement design of the product is a result that design to make to promote the advertisement directly the product,Proceed the market expansion.Making use of the real object measures fast anti of proceeding beg to set up mold is current investigative a little bit hot of a,It is an important technique that product imitate the type foundation go forward a line of the product modification designs.Its basic principle is to passes three coordinateses measure the machine, laser measure machine or electronicses copy the few ÒÇ to proceed to scan the diagraph to the real object,The data of large quantity that arithmetic figure turn that gets to measures the acquisition orders anti that send into the high class CAD software beg mold piece or appropriative anti beg the software inside, anti beg the software can read directly a data cluster,Combining can proceed the editor, filter, tidy up, beg the ¾« to a data cluster, row preface, part modification and reorganization, then automatic born curved face, It is end to acquire together the real object precision is consistent of or computer EU a product model that pass through reforms.This way can increases biggest new product design velocity.Current mature curved face anti beg to set up the mold software has: Surfacer,Cimatronrenge, etc. of Strim100.Make use of the standard format document of the other the system of CAD to set up the mold, this way than convenience.Because the world of the market turns with the technical development in the network of INTERNET,The CAD technique exchanges of the molding tool business enterprise with cooperate to have many pass the CAD document method proceed.Because the CAD system category is more, therefore documentary format must follow the international standard,Such as the DXF, IGES, STEP, VDA, etc. of STL.Pass to read standard format document to establish directly or establish the product model after modifying, since canquickly, deepen the customer and the exchanges of the molding tool factory house, Also can shorten the product the design the period.3, the CAD design of the molding tool and analysisThe CAD design of the molding tool, analysis,Include to divide the type, certain type C» according to the product model molding tool of proceeding the design with the type D¾ , molding tool structural and detailed design, the plastics ³a fills process analysis etc. a few aspects.Make use of the advanced characteristic shape software,such as PRO/ E, etc. of UGII, the very easily certain dividing the type,Born top and bottom mold C» with mold D¾, then the proceeding flows a way, sprinkle a people and cool off the pipe line of arrange etc..Made sure these designses data hereafter, then make use of the molding tool analysis software,Proceed such as the MOLDFLOW, CFLOW the plastics take shape the process analysis.According to the software of MOLDFOLW with it of the material, craft database of plentifulness, pass the importation take shape the craft parameter,Can the development imitate the true analysis plastics to inject in note EU mold C» the process flows the circumstance( the plastics with sprinkle a people more inject remits to flow the analysis of ÎAE ), analyze the temperature pressure variety circumstance and analyze to note EU a ²D remaining should dint etc.,According to analyze the circumstance to the rationality that check the molding tool construction, flow quantity problem etc. of the rationality, product of the appearance.For example whether the esse sprinkles to note the system not reasonable, appear to flow way with sprinkle a position size not appropriate,Can''t equilibrium alive with type C» ; whether to exsit product construction absurdity or molding tool constructions or not is not reasonable, appearing the product A dissatisfied( namely short shoot the phenomenon); whether to cool off asymmetry or not, the influence produces the efficiency with product quantity;Whether the esse notes the craft of EU wrong, appear the song of CI of the product transform etc..The molding tool passes the CAD the design with analyze, can dissolvemistake at design the stage, increase to try once the mold the success the rate.At plastics molding tool design with analyze to apply many new computer.aideds technique this stage, if the parameter turns technique, characteristic shape technique, database technique etc..There is many standards piece in the plastics molding tool, Turn such as the standard mold a parameter for outing organization, sprinkling noting system, cooling system...etc. can adopting basing on database managing the characteristic shape design method proceed the design or establish the standard a a, like this since can realize the data share,Can satisfy the customer again to the at any time modifying of the design, make the design analysis of the molding tool fast, accurate, efficiently.The parameter turns the characteristic shape can not only describe the product completely then several why sketch information,And can acquire accuracy, material and assemble etc. informations of the product, its a product for establishing model is a kind of apting to handle and can reflect design intention with process the model of the characteristic.Therefore,The parameter turns the characteristic shape technique is an one of the most important technique in process in manufacturing in molding tools.4, the technical application in CAM of the molding tool, process to imitate true and ml;I processing, line incising to process, electricity spark processing to wait.The technique of CAM rises in the type C» , type D¾ of the complicated molding tool and the I I of the electrodes process particularly more important function.Its main technique characteristics includes:(1) the O , ¾« processes the knife have the track excellent to turn the programming with the instruction of NC creation,(2) the knife has the category, characteristic to establish with the material ,(3) slicing the Ï÷ process the craft parameter to really settle,(4)The commonness slices the Ï÷ to slice with the high speed the characteristic that I process controls,(5) over slice the check with process the superficial accuracy control,(6)processing the computer entity of the process imitate the realistic I ,(7) The computer control number controls the technique of DNC and clusters of the machine bed control the technical and applied etc..Need the CAD specially in technical application in CAM three I product model data.More profession computer plait distance software,such as MASTERCAM, UNIMOD, etc. of CIMATRON, when the plait distance of many curved faces processes have the higher request to the curved face model of the product,Intend with the high accuracy of the curved face to match such as the directional consistency, curved face in U, V of the close together curved face, inclined rate in curved face continuous variety etc..In high class CAD/ the integral whole of CAM turn system,( such as UGII, PRO/ E)Because making use of the parameter turns the characteristic shape design with same database technique, making the type C of the product model data, molding tool have the track data to have got the inside contact with the type D¾ model data, knife, The modification knife of the product model has the track to also modify automatically.The molding tool processes the entity imitates the true technique more and more mature, also is more and more valued by people.It is mimicry machine bed that processing the entity imitate process the process on the computer, can keep the result that view reflect process,Can takes the gauge of directly quantity that after processing spare parts, can check the mistake that process.At check quantity that after processing spare parts, can at the computer is last to process behind of the entity model proceeds the aleatoric EE slices, Measure its size directly with the accuracy.Therefore, it can dissolve mistake at process the stage of craft plait distance design, reduce to repair after processing with return the work, increases consumedly the manufacturing efficiency of the molding tool with quantity.5, plastics product and its molding tools take shape the manufacturing quicklyPlastics product and its molding tools use the computer CAD techniquewdesignafter completing, can pass the fleetness take shape the technique make.This is the manufacturing technique of a kind of all new concept,It abandoned the traditional machine processes the method.Its take shape principle is three I CAD entity models are long.lost set up a series of a layer data of the thickness, make use of the laser take shape machine or others take shape the equipments read these datas,Increase the method technique with the material, pile up the each layer to take shape one by one in order.This technique calls the fleetness to take shape the technique automatically.( Rapid Prototype)It is also a CAD to gather the technical importance constitutes the part.The first pedestal takes shape the equipments quickly to bear in the United States a company in 1987, because of its characteristics is to has nothing to do with the complicated degree of the product of the manufacturing, bringing the manufacturing industry the enormous vibration.Henceforth decade,Take shape quickly the technique be flown to develop soon, the category of the equipments also piles up one after another,Turn from the material I the method can is divided into the laser with not the laser burns the knot method( SLS), solid surface layer shape method( SGC), layer a manufacturing method( LOM) and melt to sink to accumulate the method( FDM), district constituency glues the knot method( DSPC), laser spirit to sink to accumulate method( SALD) etc. mutually.Every kind of method characteristics is:The method of SLA is applied at the earliest stage of took shape the technique quickly, the early market occupied the bigger cent sum, but is narrow because of the material scope, the cost is higher, taking shape the piece was heat.proof and bore the burthen with applied color the ability low,The recent years was gradually replaced by the other method.The method of FDM because of taking shape the speed quick, the cost is low, get the good application in plastics product profession, because the size of the spare parts is small, accuracy bad, Also suffer certainly of restrict.The method of LOM because of adoption paper or isoutline edge that thin slice plastics, the cost is low, and the laser projects light upon each layer only, as a result take shape the speed quick,But the product surface quantity is bad.The method of SLS proceeds to burn the knot with the laser, adoptive material than wide, if the plastics,A¯ anticipates, porcelain and ceramics, metals etc. all can take shape, taking shape the piece is heat.proof and bear the burthen with apply color the ability stronger,Have the extensive and applied foreground.The other method also gets the application in some special kinds process.According to above take shape the method characteristics, take shape the technical function quickly to consist in primarily:The manufacturing useds for the design with the on trial product model, make to used for the small the molding tool that batch quantity produce to process with the special spare parts in small batch quantity.Take shape the product model of the technique manufacturing quickly in the aspects of material the ratio tradition processes the product model of the method manufacturing has the difference,But in shape and sizes almost complete similar, and there is certain machine strength, can make the function experiment, handles through surface at the same time, looking similar to true product,Can advertise the propaganda material.Take shape the molding tool of the technique manufacturing quickly,Is a soft material to take shape the mold( the mold of A¯ , wreath oxygen resin mold, ¹è rubber mold, low EU orders the metal alloy casts mold etc.) primarily to synthesize the hard type in material C mold with porcelain and ceramics or metals »ùs now.Hard mold in manufacturing the hour can take shape with the fleetness the spare parts makes the female die,Create first the soft mold between wreath oxygen resin mold or other material, sprinkle to note porcelain and ceramics or gypsum molds in soft mold, then sprinkle the steel of Öý steel mold; or sprinkle the admixture that note in soft mold chemistry contain steel powder glue knot,Proceed to burn to become the steel mold.Take shape the steel mold of the technique manufacturing quickly to process after needing further did to throw light etc., make into the small batch quantity produce of note the mold of EU .Because the molding tool sprinkles to note or burn the knot with the steel powder but, Material and common molding tool steel contain certain margin, therefore, the life span is shorter, cans make to manufacture on a trial basis product or small batch quantities produce.Moreover, taking shape the technique quickly can also manufacture the special spare parts,If make with the metallurgy powder legal system the metals electrode, nicety cast the legal system makes the copper electrode, ND mold legal system makes graphite electrode etc..Take shape the technique creation molding tool quickly to model the equipments with the product, all is STL to read CAD system creation or CLI etc. document format datas,Different document format data to the product accuracy of the creation contain bigger margin, therefore, study the system of CAD to take shape quickly the document format of the equipments output to have the very important meaning.6, the molding tool CAD gathers technical development trendA calculator for saying, molding tool CAD gathering technique is applying in molding tool making each link assistance technique on the ×U with each link information that realizes the technique gathers.Obviously,The information gathers unify with data the management is a key.The information of the product is to pierces through in the design, analyze, process, examine, assemble a stage,Fluency, solution data format that realizes each link information standardizes and the data maintenance is a point with future CAD that share to gather technique development.The system of PDM emergence is to resolve this problem brought the first light of day.It is molding tool business enterprise application CAD that the system of PDM puts into practice gather technical and important lesson.Design in molding toolmanufacturing aspect,The intelligence that imply the research, high speed that abundant expert''s knowledge turn molding tool CAD/ the system of CAM slices theI÷ processes and its plait distance etc. is a trend that future study the development.2 中文翻译塑料模具CAD集成技术内容提要：通过分析计算机辅助注射模设计和制造的各个环节中共享的技术和信息，本文揭示了注射模CAD的集成技术的根本内涵，并提出了它的研究热点和趋势。

毕业设计(论文)外文资料翻译(学生用)

毕业设计外文资料翻译学院：信息科学与工程学院专业：软件工程姓名： XXXXX学号： XXXXXXXXX外文出处： Think In Java (用外文写)附件： 1.外文资料翻译译文；2.外文原文。

附件1：外文资料翻译译文网络编程历史上的网络编程都倾向于困难、复杂，而且极易出错。

程序员必须掌握与网络有关的大量细节，有时甚至要对硬件有深刻的认识。

一般地，我们需要理解连网协议中不同的“层”（Layer）。

而且对于每个连网库，一般都包含了数量众多的函数，分别涉及信息块的连接、打包和拆包；这些块的来回运输；以及握手等等。

这是一项令人痛苦的工作。

但是，连网本身的概念并不是很难。

我们想获得位于其他地方某台机器上的信息，并把它们移到这儿；或者相反。

这与读写文件非常相似，只是文件存在于远程机器上，而且远程机器有权决定如何处理我们请求或者发送的数据。

Java最出色的一个地方就是它的“无痛苦连网”概念。

有关连网的基层细节已被尽可能地提取出去，并隐藏在JVM以及Java的本机安装系统里进行控制。

我们使用的编程模型是一个文件的模型；事实上，网络连接（一个“套接字”）已被封装到系统对象里，所以可象对其他数据流那样采用同样的方法调用。

除此以外，在我们处理另一个连网问题——同时控制多个网络连接——的时候，Java内建的多线程机制也是十分方便的。

本章将用一系列易懂的例子解释Java的连网支持。

15.1 机器的标识当然，为了分辨来自别处的一台机器，以及为了保证自己连接的是希望的那台机器，必须有一种机制能独一无二地标识出网络内的每台机器。

早期网络只解决了如何在本地网络环境中为机器提供唯一的名字。

但Java面向的是整个因特网，这要求用一种机制对来自世界各地的机器进行标识。

为达到这个目的，我们采用了IP（互联网地址）的概念。

IP以两种形式存在着：(1) 大家最熟悉的DNS（域名服务）形式。

我自己的域名是。

所以假定我在自己的域内有一台名为Opus的计算机，它的域名就可以是。

冲压模具设计成型方面毕业设计外文翻译

毕业设计（论文）英文翻译课题名称系部材料工程系专业材料成型及控制工程班级学号姓名指导教师2 0 10年3 月 10日4 Sheet metal forming and blanking4.1 Principles of die manufacture4.1.1 Classification of diesIn metalforming,the geometry of the workpiece is established entirely or partially by the geometry of the die.In contrast to machining processes,ignificantly greater forces are necessary in forming.Due to the complexity of the parts,forming is often not carried out in a single operation.Depending on the geometry of the part,production is carried out in several operational steps via one or several production processes such as forming or blanking.One operation can also include several processes simultaneously(cf.Sect.2.1.4).During the design phase,the necessary manufacturing methods as well as the sequence and number of production steps are established in a processing plan(Fig.4.1.1).In this plan,the availability of machines,the planned production volumes of the part and other boundary conditions are taken into account.The aim is to minimize the number of dies to be used while keeping up a high level of operational reliability.The parts are greatly simplified right from their design stage by close collaboration between the Part Design and Production Departments in order to enable several forming and related blanking processes to be carried out in one forming station.Obviously,the more operations which are integrated into a single die,the more complex the structure of the die becomes.The consequences are higher costs,a decrease in output and a lower reliability.Fig.4.1.1 Production steps for the manufacture of an oil sumpTypes of diesThe type of die and the closely related transportation of the part between dies is determined in accordance with the forming procedure,the size of the part in question and the production volume of parts to be produced.The production of large sheet metal parts is carried out almost exclusively using single sets of dies.Typical parts can be found in automotive manufacture,the domestic appliance industry and radiator production.Suitable transfer systems,for example vacuum suction systems,allow the installation of double-action dies in a sufficiently large mounting area.In this way,for example,the right and left doors of a car can be formed jointly in one working stroke(cf.Fig.4.4.34).Large size single dies are installed in large presses.The transportation of the parts from one forming station to another is carried out mechanically.In a press line with single presses installed one behind the other,feeders or robots can be used(cf.Fig.4.4.20 to 4.4.22),whilst in large-panel transfer presses,systems equipped with gripper rails(cf.Fig.4.4.29)or crossbar suction systems(cf.Fig.4.4.34)are used to transfer the parts.Transfer dies are used for the production of high volumes of smaller and medium size parts(Fig.4.1.2).They consist of several single dies,which are mounted on a common base plate.The sheet metal is fed through mostly in blank form and also transported individually from die to die.If this part transportation is automated,the press is called a transfer press.The largest transfer dies are used together with single dies in large-panel transfer presses(cf.Fig.4.4.32).In progressive dies,also known as progressive blanking dies,sheet metal parts are blanked in several stages;generally speaking no actual forming operation takes place.The sheet metal is fed from a coil or in the form of metal ing an appropriate arrangement of the blanks within the available width of the sheet metal,an optimal material usage is ensured(cf.Fig.4.5.2 to 4.5.5). The workpiece remains fixed to the strip skeleton up until the laFig.4.1.2 Transfer die set for the production of an automatic transmission for an automotive application-st operation.The parts are transferred when the entire strip is shifted further in the work flow direction after the blanking operation.The length of the shift is equal to the center line spacing of the dies and it is also called the step width.Side shears,very precise feeding devices or pilot pins ensure feed-related part accuracy.In the final production operation,the finished part,i.e.the last part in the sequence,is disconnected from the skeleton.A field of application for progressive blanking tools is,for example,in the production of metal rotors or stator blanks for electric motors(cf.Fig.4.6.11 and 4.6.20).In progressive compound dies smaller formed parts are produced in several sequential operations.In contrast to progressive dies,not only blanking but also forming operations are performed.However, the workpiece also remains in the skeleton up to the last operation(Fig.4.1.3 and cf.Fig.4.7.2).Due to the height of the parts,the metal strip must be raised up,generally using lifting edges or similar lifting devices in order to allow the strip metal to be transported mechanically.Pressed metal parts which cannot be produced within a metal strip because of their geometrical dimensions are alternatively produced on transfer sets.Fig.4.1.3 Reinforcing part of a car produced in a strip by a compound die setNext to the dies already mentioned,a series of special dies are available for special individual applications.These dies are,as a rule,used separately.Special operations make it possible,however,for special dies to be integrated into an operational Sequence.Thus,for example,in flanging dies several metal parts can be joined together positively through the bending of certain metal sections(Fig.4.1.4and cf.Fig.2.1.34).During this operation reinforcing parts,glue or other components can be introduced.Other special dies locate special connecting elements directly into the press.Sorting and positioning elements,for example,bring stamping nuts synchronised with the press cycles into the correct position so that the punch heads can join them with the sheet metal part(Fig.4.1.5).If there is sufficient space available,forming and blanking operations can be carried out on the same die.Further examples include bending,collar-forming,stamping,fine blanking,wobble blanking and welding operations(cf.Fig.4.7.14 and4.7.15).Fig.4.1.4 A hemming dieFig.4.1.5 A pressed part with an integrated punched nut4.1.2 Die developmentTraditionally the business of die engineering has been influenced by the automotive industry.The following observations about the die development are mostly related to body panel die construction.Essential statements are,however,made in a fundamental context,so that they are applicable to all areas involved with the production of sheet-metal forming and blanking dies.Timing cycle for a mass produced car body panelUntil the end of the 1980s some car models were still being produced for six to eight years more or less unchanged or in slightly modified form.Today,however,production time cycles are set for only five years or less(Fig.4.1.6).Following the new different model policy,the demands ondie makers have also changed prehensive contracts of much greater scope such as Simultaneous Engineering(SE)contracts are becoming increasingly common.As a result,the die maker is often involved at the initial development phase of the metal part as well as in the planning phase for the production process.Therefore,a much broader involvement is established well before the actual die development is initiated.Fig.4.1.6 Time schedule for a mass produced car body panelThe timetable of an SE projectWithin the context of the production process for car body panels,only a minimal amount of time is allocated to allow for the manufacture of the dies.With large scale dies there is a run-up period of about 10 months in which design and die try-out are included.In complex SE projects,which have to be completed in 1.5 to 2 years,parallel tasks must be carried out.Furthermore,additional resources must be provided before and after delivery of the dies.These short periods call for pre-cise planning,specific know-how,available capacity and the use of the latest technological and communications systems.The timetable shows the individual activities during the manufacturing of the dies for the production of the sheet metal parts(Fig.4.1.7).The time phases for large scale dies are more or less similar so that this timetable can be considered to be valid in general.Data record and part drawingThe data record and the part drawing serve as the basis for all subsequent processing steps.They describe all the details of the parts to be produced. The information given in theFig.4.1.7 Timetable for an SE projectpart drawing includes: part identification,part numbering,sheet metal thickness,sheet metal quality,tolerances of the finished part etc.(cf.Fig.4.7.17).To avoid the production of physical models(master patterns),the CAD data should describe the geometry of the part completely by means of line,surface or volume models.As a general rule,high quality surface data with a completely filleted and closed surface geometry must be made available to all the participants in a project as early as possible.Process plan and draw developmentThe process plan,which means the operational sequence to be followed in the production of the sheet metal component,is developed from the data record of the finished part(cf.Fig.4.1.1).Already at this point in time,various boundary conditions must be taken into account:the sheet metal material,the press to be used,transfer of the parts into the press,the transportation of scrap materials,the undercuts as well as thesliding pin installations and their adjustment.The draw development,i.e.the computer aided design and layout of the blank holder area of the part in the first forming stage–if need bealso the second stage–,requires a process planner with considerable experience(Fig.4.1.8).In order to recognize and avoid problems in areas which are difficult to draw,it is necessary to manufacture a physical analysis model of the draw development.With this model,theforming conditions of the drawn part can be reviewed and final modifications introduced,which are eventually incorporated into the data record(Fig.4.1.9).This process is being replaced to some extent by intelligent simulation methods,throughwhich the potential defects of the formed component can be predicted and analysed interactively on the computer display.Die designAfter release of the process plan and draw development and the press,the design of the die can be started.As a rule,at this stage,the standards and manufacturing specifications required by the client must be considered.Thus,it is possible to obtain a unified die design and to consider the particular requests of the customer related to warehousing of standard,replacement and wear parts.Many dies need to be designed so that they can be installed in different types of presses.Dies are frequently installed both in a production press as well as in two different separate back-up presses.In this context,the layout of the die clamping elements,pressure pins and scrap disposal channels on different presses must be taken into account.Furthermore,it must be noted that drawing dies working in a single-action press may be installed in a double-action press(cf.Sect.3.1.3 and Fig.4.1.16).Fig.4.1.8 CAD data record for a draw developmentIn the design and sizing of the die,it is particularly important to consider the freedom of movement of the gripper rail and the crossbar transfer elements(cf.Sect.4.1.6).These describe the relative movements between the components of the press transfer system and the die components during a complete press working stroke.The lifting movement of the press slide,the opening and closing movements of the gripper rails and the lengthwise movement of the whole transfer are all superimposed.The dies are designed so that collisions are avoided and a minimum clearance of about 20 mm is set between all the moving parts.4 金属板料的成形及冲裁4. 模具制造原理4.1.1模具的分类在金属成形的过程中，工件的几何形状完全或部分建立在模具几何形状的基础上的。

文献翻译-快速成型与虚拟成型在产品设计和制造中的应用

编号：毕业设计（论文）外文翻译（译文）学院：国防生学院专业：机械设计制造及其自动化学生姓名：学号：指导教师单位：姓名：职称：2014年3月9日目录快速成型与虚拟成型在产品设计和制造中的应用 (1)基于弯折的模具寿命预测 (9)快速成型与虚拟成型在产品设计和制造中的应用C.K.Chua1, S. H.Tech1,and R.K.Gay1School of Mechanical & Production Engineering; and Gintic Intitute of Manufacturing Techniology,Nanyang Technological University,Singapore引言快速成型是一种从不需任何加工或数控加工程序就得到实体形状的加工过程。

这种技术归诸与阶段制造，材料储存制造业，剩余材料制造，固体形式制造和立体印刷。

在前十年中，一批RP技术得到了发展。

在制造模型中这些技术应用不同的方法和材料，给出不同的收缩量，表面精度和准确度。

VP是一种已经成熟的在计算机模式下执行分析和模拟。

近而像基于实体上一样执行同样的测试。

有时，VP也会涉及到CAE分析和工程模拟。

本论文就着两种技术的联系描述了它们的对比研究。

这次课题研究了两种技术在成型方面的适用性和效率。

这只是总体设计和制造中的一个环节。

关键词：产品设计，快速成型，虚拟成型1. 前言RP做为一种关键的技术正在发展。

它能迅速成型出复杂的零件。

它还能使产品设计人员缩短产品设计和开发周期。

即将到来的这种技术的时代已在当今的CAD系统中的STL反映出来。

STL是一种德国标准，在RP系统中代表实体3D模型。

当RP是一种较新的技术时，VP已经在70年代很多领域里得到了稳定的发展。

采用虚拟成型意味着在计算机上分析3D模型。

现在VP通常综合了CAD/CAM软件，并且涉及到CAE文件包。

RP能在不首先制造这个零件时用一种模拟的方式来测试零件的情况。

文献翻译原文-一个描述电铸镍壳在注塑模具的应用的技术研究

编号：毕业设计(论文)外文翻译（原文）学院：国防生学院专业：机械设计制造及其自动化学生姓名：学号：指导教师单位：姓名：职称：2014年 3 月9 日technical note on the characterization of electroformed nickel shells for their application to injection molds——a Universidad de Las Palmas de Gran Canaria, Departamento de Ingenieria Mecanica, SpainAbstractThe techniques of rapid prototyping and rapid tooling have been widely developed during the last years. In this article, electroforming as a procedure to make cores for plastics injection molds is analysed. Shells are obtained from models manufactured through rapid prototyping using the FDM system. The main objective is to analyze the mechanical features of electroformed nickel shells, studying different aspects related to their metallographic structure, hardness, internal stresses and possible failures, by relating these features to the parameters of production of the shells with an electroforming equipment. Finally a core was tested in an injection mold. Keywords: Electroplating; Electroforming; Microstructure; Nickel1. IntroductionOne of the most important challenges with which modern industry comes across is to offer the consumer better products with outstanding variety and time variability (new designs). For this reason, modern industry must be more and more competitive and it has to produce with acceptable costs. There is no doubt that combining the time variable and the quality variable is not easy because they frequently condition one another; the technological advances in the productive systems are going to permit that combination to be more efficient and feasible in a way that, for example, if it is observed the evolution of the systems and techniques of plastics injection, we arrive at the conclusion that, in fact, it takes less and less time to put a new product on the market and with higher levels of quality. The manufacturing technology of rapid tooling is, in this field, one of those technological advances that makes possible the improvements in the processes of designing and manufacturing injected parts. Rapid tooling techniques are basically composed of a collection of procedures that are going to allow us to obtain a mold of plastic parts, in small or medium series, in a short period of time and with acceptable accuracy levels. Their application is not only included in the field of making plastic injected pieces [1], [2] and [3], however, it is true that it is where they have developed more and where they find the highest output. This paper is included within a wider research line where it attempts to study, define, analyze, test and propose, at an industrial level, the possibility of creating cores forinjection molds starting from obtaining electroformed nickel shells, taking as an initial model a prototype made in a FDM rapid prototyping equipment.It also would have to say beforehand that the electroforming technique is not something new because its applications in the industry are countless [3], but this research work has tried to investigate to what extent and under which parameters the use of this technique in the production of rapid molds is technically feasible. All made in an accurate and systematized way of use and proposing a working method.2. Manufacturing process of an injection moldThe core is formed by a thin nickel shell that is obtained through the electroforming process, and that is filled with an epoxic resin with metallic charge during the integration in the core plate [4] This mold (Fig. 1) permits the direct manufacturing by injection of a type a multiple use specimen, as they are defined by the UNE-EN ISO 3167 standard. The purpose of this specimen is to determine the mechanical properties of a collection of materials representative industry, injected in these tools and its coMParison with the properties obtained by conventional tools.Fig. 1. Manufactured injection mold with electroformed core.The stages to obtain a core [4], according to the methodology researched in this work, are the following:(a) Design in CAD system of the desired object.(b) Model manufacturing in a rapid prototyping equipment (FDM system). The material used will be an ABS plastic.(c) Manufacturing of a nickel electroformed shell starting from the previous model that has been coated with a conductive paint beforehand (it must have electrical conductivity).(d) Removal of the shell from the model.(e) Production of the core by filling the back of the shell with epoxy resin resistant to high temperatures and with the refrigerating ducts made with copper tubes.The injection mold had two cavities, one of them was the electroformed core and the other was directly machined in the moving platen. Thus, it was obtained, with the same tool and in the same process conditions, to inject simultaneously two specimens in cavities manufactured with different technologies.3. Obtaining an electroformed shell: the equipmentElectrodeposition [5] and [6] is an electrochemical process in which a chemical change has its origin within an electrolyte when passing an electric current through it. The electrolytic bath is formed by metal salts with two submerged electrodes, an anode (nickel) and a cathode (model), through which it is made to pass an intensity coming from a DC current. When the current flows through the circuit, the metal ions present in the solution are transformed into atoms that are settled on the cathode creating a more or less uniform deposit layer.The plating bath used in this work is formed by nickel sulfamate [7] and [8] at a concentration of 400 ml/l, nickel chloride (10 g/l), boric acid (50 g/l), Allbrite SLA (30 cc/l) and Allbrite 703 (2 cc/l). The selection of this composition is mainly due to the type of application we intend, that is to say, injection molds, even when the injection is made with fibreglass. Nickel sulfamate allows us to obtain an acceptable level of internal stresses in the shell (the tests gave results, for different process conditions, not superior to 50 MPa and for optimum conditions around 2 MPa). Nevertheless, such level of internal pressure is also a consequence of using as an additive Allbrite SLA, which is a stress reducer constituted by derivatives of toluenesulfonamide and by formaldehyde in aqueous solution. Such additive also favours the increase of the resistance of the shell when permitting a smaller grain. Allbrite 703 is an aqueous solution of biodegradable surface-acting agents that has been utilized to reduce the risk of pitting. Nickel chloride, in spite of being harmful for the internal stresses, is added to enhance the conductivity of the solution and to favour the uniformity in the metallic distribution in the cathode. The boric acid acts as a pH buffer.The equipment used to manufacture the nickel shells tested has been as follows:• Polypropylene tank: 600 mm × 400 mm × 500 mm in size.• Three teflon resistors, each one with 800 W.• Mechanical stirring system of the cathode.• System for recirculation and f iltration of the bath formed by a pump and a polypropylene filter.• Charging rectifier. Maximum intensity in continuous 50 A and continuous current voltage between 0 and 16 V.• Titanium basket with nickel anodes (Inco S-Rounds Electrolytic Nickel) with a purity of 99%.• Gases aspiration system.Once the bath has been defined, the operative parameters that have been altered for testing different conditions of the process have been the current density (between 1 and 22 A/dm2), the temperature (between 35 and 55 °C) and the pH, partially modifying the bath composition.4. Obtained hardnessOne of the most interesting conclusions obtained during the tests has been that the level of hardness of the different electroformed shells has remained at rather high and stable values. In Fig. 2, it can be observed the way in which for current density values between 2.5 and 22 A/dm2, the hardness values range from 540 and 580 HV, at pH4 ± 0.2 and with a temperature of 45 °C. If the pH of the bath is reduced at 3.5 and the temperature is 55 °C those values are above 520 HV and below 560 HV. This feature makes the tested bath different from other conventional ones composed by nickel sulfamate, allowing to operate with a wider range of values; nevertheless, such operativity will be limited depending on other factors, such as internal stress because its variability may condition the work at certain values of pH, current density or temperature. On the other hand, the hardness of a conventional sulfamate bath is between 200–250 HV, much lower than the one obtained in the tests. It is necessary to take into account that, for an injection mold, the hardness is acceptable starting from 300 HV. Among the most usual materials for injection molds it is possible to find steel for improvement (290 HV), steel for integral hardening (520–595 HV), casehardened steel (760–800 HV), etc., in such a way that it can be observed that the hardness levels of the nickel shells would be within the medium–high range of the materials for injection molds. The objection to the low ductility of the shell is compensated in such a way with the epoxy resin filling that would follow it because this is the one responsible for holding inwardly the pressure charges of the processes of plastics injection; this is the reason why it is necessary for the shell to have a thickness as homogeneous as possible (above a minimum value) and with absence of important failures such as pitting.Fig. 2. Hardness variation with current density. pH 4 ± 0.2, T = 45 °C.5. Metallographic structureIn order to analyze the metallographic structure, the values of current density and temperature were mainly modified. The samples were analyzed in frontal section and in transversal section (perpendicular to the deposition). For achieving a convenient preparation, they were conveniently encapsulated in resin, polished and etched in different stages with a mixture of acetic acid and nitric acid. The etches are carried out at intervals of 15, 25, 40 and 50 s, after being polished again, in order to be observed afterwards in a metallographic microscope Olympus PME3-ADL 3.3×/10×.Before going on to comment the photographs shown in this article, it is necessary to say that the models used to manufacture the shells were made in a FDM rapid prototyping machine where the molten plastic material (ABS), that later solidifies, is settled layer by layer. In each layer, the extruder die leaves a thread approximately 0.15 mm in diameter which is compacted horizontal and vertically with the thread settled inmediately after. Thus, in the surface it can be observed thin lines that indicate the roads followed by the head of the machine. These lines are going to act as a reference to indicate the reproducibility level of the nickel settled. The reproducibility of the model is going to be a fundamental element to evaluate a basic aspect of injection molds: the surface texture.The tested series are indicated in Table 1.Table 1.Tested seriesSeries pH Temperature(°C) Current density (A/dm2)1 4.2 ± 0.2 55 2.222 3.9 ± 0.2 45 5.563 4.0 ± 0.2 45 10.004 4.0 ± 0.2 45 22.22Fig. 3 illustrates the surface of a sample of the series after the first etch. It shows the roads originated by the FDM machine, that is to say that there is a good reproducibility. It cannot be still noticed the rounded grain structure. In Fig. 4, series 2, after a second etch, it can be observed a line of the road in a way less clear than in the previous case. In Fig. 5, series 3 and 2° etch it begins to appear the rounded grainstructure although it is very difficult to check the roads at this time. Besides, the most darkened areas indicate the presence of pitting by inadequate conditions of process and bath composition.Fig. 3. Series 1 (×150), etch 1.Fig. 4. Series 2 (×300), etch 2.Fig. 5. Series 3 (×300), etch 2.This behavior indicates that, working at a low current density and a high temperature, shells with a good reproducibility of the model and with a small grain size are obtained, that is, adequate for the required application.If the analysis is carried out in a plane transversal to the deposition, it can be tested in all the samples and for all the conditions that the growth structure of the deposit is laminar (Fig. 6), what is very satisfactory to obtain a high mechanical resistance although at the expense of a low ductibility. This quality is due, above all, to the presence of the additives used because a nickel sulfamate bath without additives normally creates a fibrous and non-laminar structure [9]. The modification until a nearly null value of the wetting agent gave as a result that the laminar structure was maintained in any case, that matter demonstrated that the determinant for such structure was the stress reducer (Allbrite SLA). On the other hand, it was also tested that the laminar structure varies according to the thickness of the layer in terms of the current density.Fig. 6. Plane transversal of series 2 (×600), etch 2.6. Internal stressesOne of the main characteristic that a shell should have for its application like an insert is to have a low level of internal stresses. Different tests at different bath temperatures and current densities were done and a measure system rested on cathode flexural tensiometer method was used. A steel testing control was used with a side fixed and the other free (160 mm length, 12.7 mm width and thickness 0.3 mm). Because the metallic deposition is only in one side the testing control has a mechanical strain (tensile or compressive stress) that allows to calculate the internal stresses. Stoney model [10] was applied and was supposed that nickel substratum thickness is enough small (3 μm) to influence, in an elastic point of view, to the strained steel part. In all the tested cases the most value of internal stress was under 50 MPa for extreme conditions and 2 MPa for optimal conditions, an acceptable value for the required application. The conclusion is that the electrolitic bath allows to work at different conditions and parameters without a significant variation of internal stresses.7. Test of the injection moldTests have been carried out with various representative thermoplastic materials such as PP, PA, HDPE and PC, and it has been analysed the properties of the injected parts such as dimensions, weight, resistance, rigidity and ductility. Mechanical properties were tested by tensile destructive tests and analysis by photoelasticity. About 500 injections were carried out on this core, remaining under conditions of withstanding many more.In general terms, important differences were not noticed between the behavior of the specimens obtained in the core and the ones from the machined cavity, for the set of the analysed materials. However in the analysis by photoelasticiy (Fig. 7) it was noticed a different tensional state between both types of specimens, basically due to differences in the heat transference and rigidity of the respective mold cavities. This difference explains the ductility variations more outstanding in the partially crystalline materials such as HDPE and PA 6.Fig. 7. Analysis by photoelasticity of injected specimens.For the case of HDPE in all the analysed tested tubes it was noticed a lower ductility in the specimens obtained in the nickel core, quantified about 30%. In the case of PA 6 this value was around 50%.8. ConclusionsAfter consecutive tests and in different conditions it has been checked that the nickel sulfamate bath, with the utilized additives has allowed to obtain nickel shells with some mechanical properties acceptable for the required application, injection molds, that is to say, good reproducibility, high level of hardness and good mechanical resistance in terms of the resultant laminar structure. The mechanical deficiencies of the nickel shell will be partially replaced by the epoxy resin that finishes shaping the core for the injection mold, allowing to inject medium series of plastic parts with acceptable quality levels.References[1] A.E.W. Rennie, C.E. Bocking and G.R. Bennet, Electroforming of rapid prototyping mandrels for electro discharge machining electrodes, J. Mater. Process. Technol.110 (2001), pp. 186–196. [2] P.K.D.V. Yarlagadda, I.P. Ilyas and P. Chrstodoulou, Development of rapid tooling for sheet metal drawing using nickel electroforming and stereo lithography processes, J. Mater. Process. Technol.111 (2001), pp. 286–294.[3] J. Hart, A. Watson, Electroforming: A largely unrecognised but expanding vital industry, Interfinish 96, 14 World Congress, Birmingham, UK, 1996.[4] M. Monzón et al., Aplicación del electroconformado en la fabricación rápida de moldes de inyección, Revista de Plásticos Modernos.84 (2002), p. 557.[5] L.F. Hamilton et al., Cálculos de Química Analítica, McGraw Hill (1989).[6] E. Julve, Electrodeposición de metales, 2000 (E.J.S.).[7] A. Watson, Nickel Sulphamate Solutions, Nickel Development Institute (1989).[8] A. Watson, Additions to Sulphamate Nickel Solutions, Nickel Development Institute (1989).[9] J. Dini, Electrodeposition Materials Science of Coating and Substrates, Noyes Publications (1993).[10] J.W. Judy, Magnetic microactuators with polysilicon flexures, Masters Report, Department of EECS, University of California, Berkeley, 1994. (cap′. 3).How Surface Treatments Keep Molds Operating LongerImportant tips and information about mold coatings to help you achieve the level ofproduction that you and your customers desire.By Steven . Bales Mold making technology January 2006AbstractThere’s an awful lot to know these days about molding plastic and how to get the very best performance from the valuable tools you build or run. This guide has been written to provide important tips and information about mold coatings. After reading this, you should have a very good idea of what coatings—from the very traditional to the very latest—will help you to achieve the level of production you and yourcustomers desire. After all, these tools are an investment and they need to be protected for the life of the products they mold.Key Wordsmold coatings preventive maintenance (PM) program benefit nickel Cobalt diamond-chromenickel-PTFE nickel-boron nitride electroless nickel textureThe Key Role of CoatingsBefore introducing you to the wide range of coatings on the market today, it’s important to note the role coatings can play in an effective preventive maintenance (PM) program.PM is really the key to protecting your tooling, your investment. Why? Because it saves time and money. Once you invest in a mold coating to improve tool performance, then a PM program is always a good idea to ensure you get the maximum benefit. These two steps should be a given in any shop.Remember, no coating lasts forever, and producing substandard parts from a mold with a worn coating is no way to win customers and stay profitable. PM is probably the most cost-effective strategy you can put in place. The key is to educate your personnel on how mold coatings wear during production. Every coating is different, so it’s of benefit to have employees learn how to tell when the coating is showing deterioration, especially in high-wear areas such as gates and runners.For example, wear in and around gate areas plated with hard chrome is the first sign that your mold needs servicing. How can you tell there is wear? The chrome coating is approximately 20 RC points harder than the base steel, so exposed steel will wear much faster than the coated surfaces surrounding it, causing a slight or pronounced edge or ―step‖ on the surface.Conversely, nickel will wear almost evenly, causing a kind of feathering effect, making it more difficult to recognize wear. A more identifiable difference will be the color because when nickel coating wears, it produces a shadow or halo effect on the steel. No step or edge will be evident. The steel also will have a more silver appearance compared to the somewhat tarnished look of the nickel coating.This knowledge makes pulling a mold for maintenance before the coating wears through an ultra important aspect of a PM program. To miss important wear signals means more costly repairs and additional polishing expense.Measuring WearA recommended tool for measuring the wear level of any coating is an electronic thickness gauge that uses a combination of magnetism and eddy current to accurately measure surface thickness. When the mold first arrives in your plant, take the time to measure the surface thickness—especially in high-wear areas—using this specialized tool. As you run production on the mold, occasionally pause to re-measure those areas. When you have determined that the finish is wearing to a critical level, pull the mold and send it out for maintenance.Part CountsBe sure to record the measurements taken with the thickness gauge and use the notes to create a history of maintenance requirements for the tool. A cycle counter installed on the mold will allow your tooling engineer to record wear levels as compared to piece part counts, thereby doubling the effectiveness of your PM program. Part counts are a great way to determine maintenance needs, especially with high-volume molding projects.From the very first time you run the mold, keep an accurate piece count until it is ready for its first maintenance work. Use that count as a gauge for when the next maintenance is due. Because you know approximately when the mold will be ready to be refurbished, you can arrange the service in advance with your coating vendor. This not only gives him ample time to schedule your mold maintenance, but it also allows you to optimize the use of the mold and the machine that’s running it.Coating ChallengesEven today, there are those who question the benefits of using fancy—sometimes more expensive—coatings to prolong tooling life or enhance performance. To some, the tried and true hard chrome or electroless nickel are all they’ll ever need to accomplish those goa ls. But we all know that today’s engineered plastic materials can be pretty rough on injection molds.Challenges to mold maintenance extend beyond glass- and mineral-fillers to include rice hulls, wood fibers, metal powders, flame retardants and other additives—not to mention the resins themselves. In addition, outgassing and moisture acidity often accompany abrasive wear, taking an even bigger toll on expensive tooling.In addition, growing complexity in mold design involves tinier, more intricate flow passages and more frequent use of moving cores and slides. All of these circumstances have prompted the development of a wider variety of mold coatings that can keep molds operating longer between repairs.New Coating ScienceIf you are molding highly intricate parts using glass-filled materials, you might think using hard chrome will be sufficient because it is a classic, reliable way to protect your mold from both corrosion and abrasion. However, hard chrome, for all its benefits, does not tend to plate uniformly in detailed areas like ribs and bosses. There is a newer solution—a nickel-cobalt alloy coating that can overcome that limitation.Nickel CobaltNickel-cobalt can be an economical alternative to hard chrome. Hard chrome requires construction of a conforming anode to coat the mold. The more detail in the mold, the more time it takes to build the anode and the more expensive the process becomes. This nickel-cobalt alloy coating requires no anode, and because of its electroless properties, it plates much more uniformly.The cobalt gives it good abrasion resistance, but its hardness is 62 RC, 10 points lower than hard chrome. Is it worth paying extra for hard chrome’s superior wear protection? You have to consider the material being run in the mold. Wha t’s the percentage of glass? Is corrosion a greater concern than abrasion?Diamond ChromeHard chrome and a nickel-cobalt alloy coating offer two very good solutions for abrasion resistance, but for very high-wear conditions, an even newer product called diamond-chrome offers exceptional protection.It has an RC rating greater than 85 and is a chromium-matrix composite coating with a dispersion of nanometer-size, spherical diamond particles. Since diamonds are unmatched for hardness, this coating offers protection beyond the norm. Though their Rockwell ratings are comparable, diamond-chrome outperforms titanium nitride (TiN) coating because it won’t compromise the dimensional integrity of the plated tool. The difference is that it is applied at only about 130oF while TiN requires application temperatures of 800oF or higher.Diamond-chrome can plate prehardened, heat-treated or nitrided steel and other base materials such as aluminum, beryllium-copper, brass and stainless steel. Recommended uses include cores, cavities, slides, ejector sleeves, and rotating and unscrewing cores. Its anti-galling properties are advantageous on moving cores and slides.Diamond-chrome also is very strippable and has no adverse effect on the base material, saving time and money when maintenance is needed. TiN is strippable as well, but it can take up to several days to remove with a peroxide-based solution. Diamond-chrome can be stripped in minutes using reverse electrolysis in a caustic solution.In addition, diamond-chrome can be deposited at any controlled thickness from 20 millionths of an inch to 0.001 in. TiN is generally only applied in thin deposits of a few millionths of an inch. Diamond-chrome can coat complex details, while TiN has very limited coverage of complex details. While TiN is very lubricious, with a coefficient of friction (COF) of 0.4 (against steel), diamond-chrome has a COF of0.15—nearly three times more lubricious.Nickel-Boron NitrideWhen it comes to molders’ needs for a specialty coating that offers exce llent release properties and high resistance to wear, heat, and corrosion, an electrolessnickel-phosphorus matrix containing boron nitride particles should be considered.It has a very low COF (0.05 against steel) and an RC hardness of 54, which can be increased to 67 RC after heat treating—a unique characteristic. Nickel-boron nitride can be applied to any substrate at only 185oF and can be easily stripped without compromising the base material. Though it is approximately 20 percent more expensive than nickel-PTFE, this coating will outperform nickel-PTFE at up to1250oF, which far surpasses the 500oF maximum limit for all PTFE-based coatings.Because applying nickel-boron nitride is an autocatalytic process, it requires no anode, therefore saving time and money. In addition, it will not compromise thermal conductivity of the mold. Applications include unscrewing cores for closures, where reduced cycle times are essential.Where lubricity is needed for better release from deep ribs, zero-draft cores, textured surfaces and ―sticky‖ polymers, a nickel-PTFE composite will greatly improve part release and enhance resin flow by as much as 4 to 8 percent for shorter cycle times. COF is 0.10 against steel.It should be noted that applying pure PTFE to the mold adds high lubricity, but only a very short-term benefit. PTFE by itself has no hardness, so it won’t last. But a dispersion of 25 percent PTFE by volume in a co-deposit with nickel results in 45 RC hardness for added wear and corrosion protection.Tried and TrueDespite the new coating science, we cannot throw out the old, reliable coatings such as like hard chrome or electroless nickel just yet. There’s no question that they still have their uses.Hard ChromeFor example, hard chrome’s top advantage is that i t has a hardness of 72 Rockwell C (RC) and is applied at the low temperature of 130oF. When applied in its purest form, it allows you to achieve any SPI finish on your tooling.。

文献翻译-注塑模具设计

编号：毕业设计(论文)外文翻译（译文）学院：机电工程学院专业：机械制造及其自动化学生姓名：学号：指导教师单位：姓名：职称：2014年 5 月26 日摘录巨大线束网络的塑料装饰构件集成的发现在汽车领域上是降低汽车重量的一个很有吸引力的方式。

当任何异物插入注射成型的部分，在聚合物中横截面的变化导致了缩痕是审美缺陷而不是塑料装饰是可以接受的组件。

在本文中，插入成型采用注射成型过程分量的方法来减少或消除缩痕线。

采用L9正交试验设计实验框架用来研究工艺参数的影响，部分的肋的几何形状，并在水槽的标记线本身存在的形成。

水槽深度被定义为在表面轮廓可以感觉到的剩余的偏转。

一个描述性的模拟研究提出在不同的肋的几何形状的观察水池深度标记的工艺参数、模具温度、熔体温度和包装的时间是不同的。

仿真结果表明，较高的模具温度可有效地最小化的下沉深度为所有的肋的几何形状，而熔体温度和包时间的影响取决于特定的肋的几何形状。

研究结果还表明，适当的组合肋的几何形状和工艺参数消除了水槽标记。

感谢我要感谢我的导师David C. Angstadt 博士的指导和在这个项目的整个过程中的信任和支持。

Angstadt 博士的不断的反馈和很高的期望，驱使我不断进取，完成这项工作。

我衷心感谢Mica Grujicic博士让我进入Moldflow。

特别感谢我的研究生同学Peiman Mosaddegh 和Celina Renner这项工作的过程中的无私帮助。

我还要感谢我的朋友Nitendra Nath，Gayatri Keskar，Sonia Ramnani，Shyam Panyam，Judhajit Roy 和Ajit Kanda的不断鼓励和帮助。

最后，我要感谢我的家人和朋友们所有的爱和关怀，如果没有这些的话，这项工作将是不完整的。

第一章引言汽车制造商正越来越多地用塑料解决方案来减轻重量。

最近的一项研究表明，塑料占了10%的汽车的总重量。

塑料在汽车从内部的保险杠到外部的门体都存在。

毕业设计(论文)外文翻译

华南理工大学广州学院本科生毕业设计（论文）翻译外文原文名Agency Cost under the Restriction of Free Cash Flow中文译名自由现金流量的限制下的代理成本学院管理学院专业班级会计学3班学生姓名陈洁玉学生学号200930191100指导教师余勍讲师填写日期2015年5月11日外文原文版出处：译文成绩：指导教师（导师组长）签名：译文：自由现金流量的限制下的代理成本摘要代理成本理论是资本结构理论的一个重要分支。

自由现金流代理成本有显着的影响。

在这两个领域相结合的研究，将有助于建立和扩大理论体系。

代理成本理论基础上，本研究首先分类自由现金流以及统计方法的特点。

此外，投资自由现金流代理成本的存在证明了模型。

自由现金流代理成本理论引入限制，分析表明，它会改变代理成本，进而将影响代理成本和资本结构之间的关系，最后，都会影响到最优资本结构点，以保持平衡。

具体地说，自由现金流增加，相应地，债务比例会降低。

关键词：资本结构，现金流，代理成本，非金钱利益1、介绍代理成本理论，金融契约理论，信号模型和新的啄食顺序理论，新的资本结构理论的主要分支。

财务con-道的理论侧重于限制股东的合同行为，解决股东和债权人之间的冲突。

信令模式和新的啄食顺序理论中心解决投资者和管理者之间的冲突。

这两种类型的冲突是在商业组织中的主要冲突。

代理成本理论认为，如何达到平衡这两种类型的冲突，资本结构是如何形成的，这是比前两次在一定程度上更多的理论更全面。

……Agency Cost under the Restriction of Free Cash FlowAbstractAgency cost theory is an important branch of capital structural theory. Free cash flow has significant impact on agency cost. The combination of research on these two fields would help to build and extend the theoretical system. Based on agency cost theory, the present study firstly categorized the characteristics of free cash flow as well as the statistical methodologies. Furthermore, the existence of investing free cash flow in agency cost was proved by a model. Then free cash flow was introduced into agency cost theory as restriction, the analysis shows that it will change agency cost, in turn, will have an impact on the relationship between agency cost and capital structure, finally, will influence the optimal capital structure point to maintain the equilibrium. Concretely, with the increasing free cash flow, correspondingly, debt proportion will decrease.Keywords:Capital Structure,Free Cash Flow,Agency Cost,Non-Pecuniary Benefit1. IntroductionAgency cost theory, financial contract theory, signaling model and new pecking order theory are the main branches of new capital structure theory. Financial con-tract theory focuses on restricting stockholders’ behavior by contract and solving the conflict between stockholders and creditors. Signaling model and new pecking order theory center on solving the conflict between investors and managers. These two types of conflict are the main conflict in business organizations. Agency cost theory considers how equilibrium is reached in both types of conflict and how capital structure is formed, which is more theory is more comprehensive than the previous two to some degree.……。

本科毕业设计(论文)外文翻译基本规范

本科毕业设计（论文）外文翻译基本规范
本科毕业设计（论文）外文翻译基本规范：
一、要求
1、与毕业论文分开单独成文。

2、两篇文献。

二、基本格式
1、文献应以英、美等国家公开发表的文献为主（Journals from English speaking countries）。

2、毕业论文翻译是相对独立的，其中应该包括题目、作者（可以不翻译）、译文的出处（杂志的名称）（5号宋体、写在文稿左上角）、关键词、摘要、前言、正文、总结等几个部分。

3、文献翻译的字体、字号、序号等应与毕业论文格式要求完全一致。

4、文中所有的图表、致谢及参考文献均可以略去，但在文献翻译的末页标注：图表、致谢及参考文献已略去(见原文)。

（空一行，字体同正文）
5、原文中出现的专用名词及人名、地名、参考文献可不翻译，并同原文一样在正文中标明出处。

三、毕业论文（设计）外文翻译的内容要求
外文翻译内容必须与所选课题相关，外文原文不少于6000个印刷符号。

译文末尾要用外文注明外文原文出处。

原文出处：期刊类文献书写方法：[序号]作者（不超过3人，多者用等或et al 表示）.题（篇）名[J].刊名（版本）,出版年，卷次（期次）：起止页次。

原文出处：图书类文献书写方法：[序号]作者.书名[M].版本.出版地：出版者,出版年.起止页次。

原文出处：论文集类文献书写方法：[序号]作者.篇名[A].编著者.论文集名[C]. 出版地：出版者，出版年.起止页次。

要求有外文原文复印件。

文献翻译-模具发展历程

编号：毕业设计(论文)外文翻译（译文）院（系）：国防生学院专业：机械设计制造及其自动化学生姓名：学号：指导教师单位：姓名：职称：2014年 3 月9 日模具发展历程威尔克斯.莫赖斯摘要功能性零部件都需要设计验证测试，车间试验，客户评价，以及生产计划。

在小批量生产零件的时候，通过消除多重步骤，建立了有快速成型形成的注塑模具，这种方法可以保证缩短时间和节约成本。

这种潜在的一体化由快速成型形成注塑模具的方法已经被多次证明是可行的。

无论是模具设计还是注塑成型的过程中，缺少的是对如何修改这个模具材料和快速成型制造过程的影响有最根本的认识。

此外，数字模拟技术现在已经成为模具设计工程师和工艺工程师开注塑模具的有用的工具。

但目前所有的做常规注塑模具的模拟包已经不再适合这种新型的注塑模具，这主要是因为模具材料的成本变化很大。

在本文中，以完成特定的数字模拟注塑液塑造成快速成型模具的综合方法已经发明出来了，而且还建立了相应的模拟系统。

通过实验结果表明，目前这个方法非常适合处理快速成型模具中的问题。

关键词：注塑成型；数字模拟；快速成型。

引言在注塑成型中，聚合物熔体在高温和高压下进入模具中。

因此，模具的材料需要有足够的热性能和机械性能来经受高温和高压的塑造循环。

许多研究的焦点都是直接有快速成型形成注塑模具的过程。

在生产小批量零件的时候，通过消除多重步骤，直接由快速成型形成的注塑模具可以保证缩短时间和节约成本。

这种潜在的有快速成型形成注塑模具的方法已经被证明成功了。

快速成型模具在性能上是有别与传统的金属模具。

主要差异是导热性能和弹性模量（刚性）。

举例来说，在立体光照成型模具中的聚合物的导热率小于铝制的工具的千分之一。

在用快速成型技术来制造铸模时，整个模具设计和注塑成型工艺参数都需要修改和优化，传统的方法是改变彻底的刀具材料．不过，目前还没有对如何修改这个模具材料的方法有根本的了解．在当前的模具中，仅仅改变一些材料的性能是不能得到一个合理的结果的。

毕业设计论文外文文献翻译

xxxx大学xxx学院毕业设计（论文）外文文献翻译系部xxxx专业xxxx学生姓名xxxx 学号xxxx指导教师xxxx 职称xxxx2013年3 月Introducing the Spring FrameworkThe Spring Framework: a popular open source application framework that addresses many of the issues outlined in this book. This chapter will introduce the basic ideas of Spring and dis-cuss the central “bean factory” lightweight Inversion-of-Control (IoC) container in detail.Spring makes it particularly easy to implement lightweight, yet extensible, J2EE archi-tectures. It provides an out-of-the-box implementation of the fundamental architectural building blocks we recommend. Spring provides a consistent way of structuring your applications, and provides numerous middle tier features that can make J2EE development significantly easier and more flexible than in traditional approaches.The basic motivations for Spring are:To address areas not well served by other frameworks. There are numerous good solutions to specific areas of J2EE infrastructure: web frameworks, persistence solutions, remoting tools, and so on. However, integrating these tools into a comprehensive architecture can involve significant effort, and can become a burden. Spring aims to provide an end-to-end solution, integrating spe-cialized frameworks into a coherent overall infrastructure. Spring also addresses some areas that other frameworks don’t. For example, few frameworks address generic transaction management, data access object implementation, and gluing all those things together into an application, while still allowing for best-of-breed choice in each area. Hence we term Spring an application framework, rather than a web framework, IoC or AOP framework, or even middle tier framework.To allow for easy adoption. A framework should be cleanly layered, allowing the use of indi-vidual features without imposing a whole worldview on the application. Many Spring features, such as the JDBC abstraction layer or Hibernate integration, can be used in a library style or as part of the Spring end-to-end solution.To deliver ease of use. As we’ve noted, J2EE out of the box is relatively hard to use to solve many common problems. A good infrastructure framework should make simple tasks simple to achieve, without forcing tradeoffs for future complex requirements (like distributed transactions) on the application developer. It should allow developers to leverage J2EE services such as JTA where appropriate, but to avoid dependence on them in cases when they are unnecessarily complex.To make it easier to apply best practices. Spring aims to reduce the cost of adhering to best practices such as programming to interfaces, rather than classes, almost to zero. However, it leaves the choice of architectural style to the developer.Non-invasiveness. Application objects should have minimal dependence on the framework. If leveraging a specific Spring feature, an object should depend only on that particular feature, whether by implementing a callback interface or using the framework as a class library. IoC and AOP are the key enabling technologies for avoiding framework dependence.Consistent configuration. A good infrastructure framework should keep application configuration flexible and consistent, avoiding the need for custom singletons and factories. A single style should be applicable to all configuration needs, from the middle tier to web controllers.Ease of testing. Testing either whole applications or individual application classes in unit tests should be as easy as possible. Replacing resources or application objects with mock objects should be straightforward.To allow for extensibility. Because Spring is itself based on interfaces, rather than classes, it is easy to extend or customize it. Many Spring components use strategy interfaces, allowing easy customization.A Layered Application FrameworkChapter 6 introduced the Spring Framework as a lightweight container, competing with IoC containers such as PicoContainer. While the Spring lightweight container for JavaBeans is a core concept, this is just the foundation for a solution for all middleware layers.Basic Building Blockspring is a full-featured application framework that can be leveraged at many levels. It consists of multi-ple sub-frameworks that are fairly independent but still integrate closely into a one-stop shop, if desired. The key areas are:Bean factory. The Spring lightweight IoC container, capable of configuring and wiring up Java-Beans and most plain Java objects, removing the need for custom singletons and ad hoc configura-tion. Various out-of-the-box implementations include an XML-based bean factory. The lightweight IoC container and its Dependency Injection capabilities will be the main focus of this chapter.Application context. A Spring application context extends the bean factory concept by adding support for message sources and resource loading, and providing hooks into existing environ-ments. Various out-of-the-box implementations include standalone application contexts and an XML-based web application context.AOP framework. The Spring AOP framework provides AOP support for method interception on any class managed by a Spring lightweight container.It supports easy proxying of beans in a bean factory, seamlessly weaving in interceptors and other advice at runtime. Chapter 8 dis-cusses the Spring AOP framework in detail. The main use of the Spring AOP framework is to provide declarative enterprise services for POJOs.Auto-proxying. Spring provides a higher level of abstraction over the AOP framework and low-level services, which offers similar ease-of-use to .NET within a J2EE context. In particular, the provision of declarative enterprise services can be driven by source-level metadata.Transaction management. Spring provides a generic transaction management infrastructure, with pluggable transaction strategies (such as JTA and JDBC) and various means for demarcat-ing transactions in applications. Chapter 9 discusses its rationale and the power and flexibility that it offers.DAO abstraction. Spring defines a set of generic data access exceptions that can be used for cre-ating generic DAO interfaces that throw meaningful exceptions independent of the underlying persistence mechanism. Chapter 10 illustrates the Spring support for DAOs in more detail, examining JDBC, JDO, and Hibernate as implementation strategies.JDBC support. Spring offers two levels of JDBC abstraction that significantly ease the effort of writing JDBC-based DAOs: the org.springframework.jdbc.core package (a template/callback approach) and the org.springframework.jdbc.object package (modeling RDBMS operations as reusable objects). Using the Spring JDBC packages can deliver much greater pro-ductivity and eliminate the potential for common errors such as leaked connections, compared with direct use of JDBC. The Spring JDBC abstraction integrates with the transaction and DAO abstractions.Integration with O/R mapping tools. Spring provides support classesfor O/R Mapping tools like Hibernate, JDO, and iBATIS Database Layer to simplify resource setup, acquisition, and release, and to integrate with the overall transaction and DAO abstractions. These integration packages allow applications to dispense with custom ThreadLocal sessions and native transac-tion handling, regardless of the underlying O/R mapping approach they work with.Web MVC framework. Spring provides a clean implementation of web MVC, consistent with the JavaBean configuration approach. The Spring web framework enables web controllers to be configured within an IoC container, eliminating the need to write any custom code to access business layer services. It provides a generic DispatcherServlet and out-of-the-box controller classes for command and form handling. Request-to-controller mapping, view resolution, locale resolution and other important services are all pluggable, making the framework highly extensi-ble. The web framework is designed to work not only with JSP, but with any view technology, such as Velocity—without the need for additional bridges. Chapter 13 discusses web tier design and the Spring web MVC framework in detail.Remoting support. Spring provides a thin abstraction layer for accessing remote services without hard-coded lookups, and for exposing Spring-managed application beans as remote services. Out-of-the-box support is inc luded for RMI, Caucho’s Hessian and Burlap web service protocols, and WSDL Web Services via JAX-RPC. Chapter 11 discusses lightweight remoting.While Spring addresses areas as diverse as transaction management and web MVC, it uses a consistent approach everywhere. Once you have learned the basic configuration style, you will be able to apply it in many areas. Resources, middle tier objects, and web components are all set up using the same bean configuration mechanism. You can combine your entireconfiguration in one single bean definition file or split it by application modules or layers; the choice is up to you as the application developer. There is no need for diverse configuration files in a variety of formats, spread out across the application.Spring on J2EEAlthough many parts of Spring can be used in any kind of Java environment, it is primarily a J2EE application framework. For example, there are convenience classes for linking JNDI resources into a bean factory, such as JDBC DataSources and EJBs, and integration with JTA for distributed transaction management. In most cases, application objects do not need to work with J2EE APIs directly, improving reusability and meaning that there is no need to write verbose, hard-to-test, JNDI lookups.Thus Spring allows application code to seamlessly integrate into a J2EE environment without being unnecessarily tied to it. You can build upon J2EE services where it makes sense for your application, and choose lighter-weight solutions if there are no complex requirements. For example, you need to use JTA as transaction strategy only if you face distributed transaction requirements. For a single database, there are alternative strategies that do not depend on a J2EE container. Switching between those transac-tion strategies is merely a matter of configuration; Spring’s consistent abstraction avoids any need to change application code.Spring offers support for accessing EJBs. This is an important feature (and relevant even in a book on “J2EE without EJB”) because the u se of dynamic proxies as codeless client-side business delegates means that Spring can make using a local stateless session EJB an implementation-level, rather than a fundamen-tal architectural, choice.Thus if you want to use EJB, you can within a consistent architecture; however, you do not need to make EJB the cornerstone of your architecture. This Spring feature can make devel-oping EJB applications significantly faster, because there is no need to write custom code in service loca-tors or business delegates. Testing EJB client code is also much easier, because it only depends on the EJB’s Business Methods interface (which is not EJB-specific), not on JNDI or the EJB API.Spring also provides support for implementing EJBs, in the form of convenience superclasses for EJB implementation classes, which load a Spring lightweight container based on an environment variable specified in the ejb-jar.xml deployment descriptor. This is a powerful and convenient way of imple-menting SLSBs or MDBs that are facades for fine-grained POJOs: a best practice if you do choose to implement an EJB application. Using this Spring feature does not conflict with EJB in any way—it merely simplifies following good practice.Introducing the Spring FrameworkThe main aim of Spring is to make J2EE easier to use and promote good programming practice. It does not reinvent the wheel; thus you’ll find no logging packages in Spring, no connection pools, no distributed transaction coordinator. All these features are provided by other open source projects—such as Jakarta Commons Logging (which Spring uses for all its log output), Jakarta Commons DBCP (which can be used as local DataSource), and ObjectWeb JOTM (which can be used as transaction manager)—or by your J2EE application server. For the same reason, Spring doesn’t provide an O/R mapping layer: There are good solutions for this problem area, such as Hibernate and JDO.Spring does aim to make existing technologies easier to use. For example, although Spring is not in the business of low-level transactioncoordination, it does provide an abstraction layer over JTA or any other transaction strategy. Spring is also popular as middle tier infrastructure for Hibernate, because it provides solutions to many common issues like SessionFactory setup, ThreadLocal sessions, and exception handling. With the Spring HibernateTemplate class, implementation methods of Hibernate DAOs can be reduced to one-liners while properly participating in transactions.The Spring Framework does not aim to replace J2EE middle tier services as a whole. It is an application framework that makes accessing low-level J2EE container ser-vices easier. Furthermore, it offers lightweight alternatives for certain J2EE services in some scenarios, such as a JDBC-based transaction strategy instead of JTA when just working with a single database. Essentially, Spring enables you to write appli-cations that scale down as well as up.Spring for Web ApplicationsA typical usage of Spring in a J2EE environment is to serve as backbone for the logical middle tier of a J2EE web application. Spring provides a web application context concept, a powerful lightweight IoC container that seamlessly adapts to a web environment: It can be accessed from any kind of web tier, whether Struts, WebWork, Tapestry, JSF, Spring web MVC, or a custom solution.The following code shows a typical example of such a web application context. In a typical Spring web app, an applicationContext.xml file will reside in the WEB-INF directory, containing bean defini-tions according to the “spring-beans” DTD. In such a bean definition XML file, business objects and resources are defined, for example, a “myDataSource” bean, a “myInventoryManager” bean, and a “myProductManager” bean. Spring takes care of their configuration, their wiring up, and their lifecycle.<beans><bean id=”myDataSource” class=”org.springframework.jdbc. datasource.DriverManagerDataSource”><property name=”driverClassName”> <value>com.mysql.jdbc.Driver</value></property> <property name=”url”><value>jdbc:mysql:myds</value></property></bean><bean id=”myInventoryManager” class=”ebusiness.DefaultInventoryManager”> <property name=”dataSource”><ref bean=”myDataSource”/> </property></bean><bean id=”myProductManager” class=”ebusiness.DefaultProductManage r”><property name=”inventoryManager”><ref bean=”myInventoryManager”/> </property><property name=”retrieveCurrentStock”> <value>true</value></property></bean></beans>By default, all such beans have “singleton” scope: one instance per context. The “myInventoryManager” bean will automatically be wired up with the defined DataSource, while “myProductManager” will in turn receive a reference to the “myInventoryManager” bean. Those objects (traditionally called “beans” in Spring terminology) need to expos e only the corresponding bean properties or constructor arguments (as you’ll see later in this chapter); they do not have to perform any custom lookups.A root web application context will be loaded by a ContextLoaderListener that is defined in web.xml as follows:<web-app><listener> <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class></listener>...</web-app>After initialization of the web app, the root web application context will be available as a ServletContext attribute to the whole web application, in the usual manner. It can be retrieved from there easily via fetching the corresponding attribute, or via a convenience method in org.springframework.web. context.support.WebApplicationContextUtils. This means that the application context will be available in any web resource with access to the ServletContext, like a Servlet, Filter, JSP, or Struts Action, as follows:WebApplicationContext wac = WebApplicationContextUtils.getWebApplicationContext(servletContext);The Spring web MVC framework allows web controllers to be defined as JavaBeans in child application contexts, one per dispatcher servlet. Such controllers can express dependencies on beans in the root application context via simple bean references. Therefore, typical Spring web MVC applications never need to perform a manual lookup of an application context or bean factory, or do any other form of lookup.Neither do other client objects that are managed by an application context themselves: They can receive collaborating objects as bean references.The Core Bean FactoryIn the previous section, we have seen a typical usage of the Spring IoC container in a web environment: The provided convenience classes allow for seamless integration without having to worry about low-level container details. Nevertheless, it does help to look at the inner workings to understand how Spring manages the container. Therefore, we will now look at the Spring bean container in more detail, starting at the lowest building block: the bean factory. Later, we’ll continue with resource setup and details on the application context concept.One of the main incentives for a lightweight container is to dispense with the multitude of custom facto-ries and singletons often found in J2EE applications. The Spring bean factory provides one consistent way to set up any number of application objects, whether coarse-grained components or fine-grained busi-ness objects. Applying reflection and Dependency Injection, the bean factory can host components that do not need to be aware of Spring at all. Hence we call Spring a non-invasive application framework.Fundamental InterfacesThe fundamental lightweight container interface is org.springframework.beans.factory.Bean Factory. This is a simple interface, which is easy to implement directly in the unlikely case that none of the implementations provided with Spring suffices. The BeanFactory interface offers two getBean() methods for looking up bean instances by String name, with the option to check for a required type (and throw an exception if there is a type mismatch).public interface BeanFactory {Object getBean(String name) throws BeansException;Object getBean(String name, Class requiredType) throws BeansException;boolean containsBean(String name);boolean isSingleton(String name) throws NoSuchBeanDefinitionException;String[] getAliases(String name) throws NoSuchBeanDefinitionException;}The isSingleton() method allows calling code to check whether the specified name represents a sin-gleton or prototype bean definition. In the case of a singleton bean, all calls to the getBean() method will return the same object instance. In the case of a prototype bean, each call to getBean() returns an inde-pendent object instance, configured identically.The getAliases() method will return alias names defined for the given bean name, if any. This mecha-nism is used to provide more descriptive alternative names for beans than are permitted in certain bean factory storage representations, such as XML id attributes.The methods in most BeanFactory implementations are aware of a hierarchy that the implementation may be part of. If a bean is not foundin the current factory, the parent factory will be asked, up until the root factory. From the point of view of a caller, all factories in such a hierarchy will appear to be merged into one. Bean definitions in ancestor contexts are visible to descendant contexts, but not the reverse.All exceptions thrown by the BeanFactory interface and sub-interfaces extend org.springframework. beans.BeansException, and are unchecked. This reflects the fact that low-level configuration prob-lems are not usually recoverable: Hence, application developers can choose to write code to recover from such failures if they wish to, but should not be forced to write code in the majority of cases where config-uration failure is fatal.Most implementations of the BeanFactory interface do not merely provide a registry of objects by name; they provide rich support for configuring those objects using IoC. For example, they manage dependen-cies between managed objects, as well as simple properties. In the next section, we’ll look at how such configuration can be expressed in a simple and intuitive XML structure.The sub-interface org.springframework.beans.factory.ListableBeanFactory supports listing beans in a factory. It provides methods to retrieve the number of beans defined, the names of all beans, and the names of beans that are instances of a given type:public interface ListableBeanFactory extends BeanFactory {int getBeanDefinitionCount();String[] getBeanDefinitionNames();String[] getBeanDefinitionNames(Class type);boolean containsBeanDefinition(String name);Map getBeansOfType(Class type, boolean includePrototypes,boolean includeFactoryBeans) throws BeansException}The ability to obtain such information about the objects managed by a ListableBeanFactory can be used to implement objects that work with a set of other objects known only at runtime.In contrast to the BeanFactory interface, the methods in ListableBeanFactory apply to the current factory instance and do not take account of a hierarchy that the factory may be part of. The org.spring framework.beans.factory.BeanFactoryUtils class provides analogous methods that traverse an entire factory hierarchy.There are various ways to leverage a Spring bean factory, ranging from simple bean configuration to J2EE resource integration and AOP proxy generation. The bean factory is the central, consistent way of setting up any kind of application objects in Spring, whether DAOs, business objects, or web controllers. Note that application objects seldom need to work with the BeanFactory interface directly, but are usu-ally configured and wired by a factory without the need for any Spring-specific code.For standalone usage, the Spring distribution provides a tiny spring-core.jar file that can be embed-ded in any kind of application. Its only third-party dependency beyond J2SE 1.3 (plus JAXP for XML parsing) is the Jakarta Commons Logging API.The bean factory is the core of Spring and the foundation for many other services that the framework offers. Nevertheless, the bean factory can easily be used stan-dalone if no other Spring services are required.Derivative：networkSpring 框架简介Spring框架：这是一个流行的开源应用框架，它可以解决很多问题。

手机壳模具建模外文翻译

X X学院本科毕业设计(论文)外文资料翻译教学单位：机电工程系专业：机械设计制造及自动化学号： XXXX姓名： XXXX附件： 1.译文；2.原文；3.评分表2010年12月译文：MasterCAM在手机壳模具建模摘要: 在网络化和数字化迅猛发展的今天，手机已经成为引领消费时尚的异军突起的工业产品。

面对日趋激烈的竞争市场和日益挑剔的消费者，如何推动手机业的持续稳定发展，已经成为手机厂商要解决的迫在眉睫的问题。

英国的前首相撒切尔夫人对工业设计曾有一句非常精辟的论断：“对于工业设计一分的投入，可以产生一千分的回报”。

美国工业设计协会做过调查，美国平均工业设计每投入一美元，其销售收入二千五百美元；日本日立公司的统计数字也表明。

每增加一千日元的销售额，工业设计的作用就占51%，而技术改造的作用仅占12%。

十分显然，工业设计的创新，必然会给产品带来丰厚的利润。

实现手机工业设计的突破和创新正是大势所趋。

关键词: MasterCAM; 手机壳模引言当前，手机市场群雄并起，逐鹿中原。

摩托罗拉、诺基亚、索尼爱立信、三星、LG五家品牌占领了中国手机市场的75%的份额。

数不胜数的其他品牌手机瓜分余下的份额。

手机牌照的放开、市场竞争者的不断涌入、市场竞争环境的恶化，使手机厂商面临前所未有的巨大压力，他们纷纷打起广告战、价格战、渠道战设产品战。

这其中产品战时重头戏，而产品的工业设计更是制胜的关键。

经过多年的努力，手机的功能设计基本可以满足消费者的需要。

随着手机的不断普及，消费者的差异化越来越明显，多层次的需求越来越强烈，对手机外观设计的要求也越来越高。

他们往往对外观设计平庸或雷同的手机不屑一顾，而对外观设计特点明显并符合自己的身份的手机情有独钟。

因此，靠创新外观设计征服消费者的发展空间还是很大的。

而面对市场的巨大挑战，手机的外观设计就要迎难而上。

手机的外观设计在适应功能设计的前提下，把外观设计和产品工艺、色彩及文化合理有机的结合，实现手机的进一步时尚化、人性化和娱乐化，这是未来中国手机外观设计的一个新趋势。

毕业设计(论文)外文文献翻译要求

毕业设计(论文)外文文献翻译要求
根据《普通高等学校本科毕业设计(论文）指导》的内容，特对外文文献翻译提出以下要求：
一、翻译的外文文献一般为1～2篇，外文字符要求不少于1。

5万（或翻译成中文后至少在3000字以上)。

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先进铸造技术动态建模过程和模具设计毕业论文中英文资料对照外文翻译文献综述

原文：《Modelling the dynamics of the tilt-casting process and the effect of the mould design on the casting quality》H. Wang a,G. Djambazov a, K.A. Pericleous a, R.A. Harding b, M. Wickins bCentre for Numerical Modelling and Process Analysis, University of Greenwich, London SE10 9LS, UK b IRC in Materials Processing, University of Birmingham, Birmingham, B15 2TT, UAbstractAll titanium alloys are highly reactive in the molten condition and so are usually melted in a water-cooled copper crucible to avoid contamination using processes such as Induction Skull Melting (ISM). These provide only limited superheat which, coupled with the surface turbulence inherent in most conventional mould filling processes, results in entrainment defects such as bubbles in the castings. To overcome these problems, a novel tilt-casting process has been developed in which the mould is attached directly to the ISM crucible holding the melt and the two are then rotated together to achieve a tranquil transfer of the metal into the mould. From the modelling point of view, this process involves complex three-phase flow, heat transfer and solidification. In this paper, the development of a numerical model of the tilt-casting process is presented featuring several novel algorithm developments introduced into a general CFD package (PHYSICA) to model the complex dynamic interaction of the liquid metal and melting atmosphere. These developments relate to the front tracking and heat transfer representations and to a casting-specific adaptation of the turbulence model to account for an advancing solid front. Calculations have been performed for a 0.4 m long turbine blade cast in a titanium aluminide alloy using different mould designs. It is shown that the feeder/basin configuration has a crucial influence on the casting quality. The computational results are validated against actual castings and are used to support an experimental programme. Although fluid flow and heat transfer are inseparable in a casting, the emphasis in this paper will be on the fluid dynamics of mould filling and its influence on cast quality rather than heat transfer and solidification which has been reported elsewhere.KeywordsTilt-casting; Mould design; 3-D computational model; Casting process；1. IntroductionThe casting process is already many centuries old, yet many researchers are still devoted to its study. Net shape casting is very attractive from the cost point of view compared to alternative component manufacturing methods such as forging or machining. However, reproducible qualityis still an issue; the elimination of defects and control of microstructure drive research. Casting involves first the filling of the mould and subsequently the solidification of the melt. From the numerical modelling point of view, this simple sequence results in a very complex three-phase problem to simulate. A range of interactions of physical phenomena are involved including free surface fluid flow as the mould fills, heterogeneous heat transfer from the metal to the mould, solidification of the molten metal as it cools, and the development of residual stresses and deformation of the solidified component.In industry there are many variants of the casting process such as sand casting, investment casting, gravity, and low and high pressure die casting. In this study, the investment casting process, also called lost-wax casting, has been investigated. One of the advantages of this process is that it is capable of producing (near) net shape parts, which is particularly important for geometrically complex and difficult-to-machine components. This process starts with making a ceramic mould which involves three main steps: injecting wax into a die to make a replica of the component and attaching this to a pouring basin and running system; building a ceramic shell by the application of several layers of a ceramic slurry and ceramic stucco to the wax assembly; de-waxing and mould firing. The pouring of the casting is performed either simply under gravity (no control), or using a rapid centrifugal action [1] (danger of macro-segregation plus highly turbulent filling), or by suction as in counter-gravity casting (e.g. the Hitchiner process[2]), or by tilt-casting. In this study, tilt-casting was chosen in an attempt to achieve tranquil mould filling. Tilt-casting was patented in 1919 by Durville [3] and has been successfully used with sand castings[4] and aluminium die castings[5]. In the IMPRESS project [6], a novel process has been proposed and successfully developed to combine Induction Skull Melting (ISM) of reactive alloys with tilt-casting[7], [8], [9] and [10], with a particular application to the production of turbine blades in titanium aluminidealloys. As shown in Fig. 1, this is carried out inside a vacuum chamber and the mould is pre-heated in situ to avoid misruns (incomplete mould filling due to premature solidification) and mould cracking due to thermal shock.Tilt-casting process: (a) experimental equipment; (b) schematic view of the ISM crucible and mould, showing the domed shape acquired by the molten metal; (c) different stages of mould filling showing the progressive replacement of gas by the metal.The component(s) to be cast are attached to a pouring basin which also doubles as a source of metal to feed the solidification shrinkage. The components are angled on the basin to promote the progressive uni-directional flow of metal into the mould. As the metal enters the mould it displaces the gas and an escape route has to be included in the design so that the two counter-flowing streams are not mixed leading to bubbles trapped in the metal. Vents are also used to enable any trapped gas to escape. The ‘feeder’ used to connect the mould to the crucible is normally in any casting the last portion of metal to solidify, so supplying metal to the mould to counter the effects of solidification shrinkage. In tilt-casting, the feeder is also the conduit for the tranquil flow of metal into the mould and also for the unhindered escape of gas. For this reason, the fluid dynamics of the mould feeder interface merit detailed study.As well as the mould/feeder design, the production of castings involves several other key parameters, such as the metal pouring temperature, initial mould temperature, selective mould insulation and the tilt cycle timing. All these parameters have an influence on the eventual quality of the casting leading to a very large matrix of experiments. Modelling (once validated) is crucial in reducing the amount of physical experiments required. As mentioned above, the mathematical models are complex due to the fact that this is a three-phase problem with two rapidly developing phase fronts (liquid/gas and solid/liquid). In this paper, a 3-D computational model is used to simulate the tilt-casting process and to investigate the effect of the design of the basin/feeder on the flow dynamics during mould filling and eventually on casting quality.2. Experimental descriptionDetails of the experimental setup have been published elsewhere [11], but for completeness a summary description is given here. Fig. 1a shows an overall view of the equipment used to perform the casting. The Induction Skull Melting (ISM) copper crucible is installed inside a vacuum chamber. To enable rotation, it is attached to a co-axial power feed, which also allows cooling water containing ethylene glycol to be supplied to the ISM crucible and the induction coil. The coil supplies a maximum of 8 kA at a frequency of ∼6 kHz. The crucible wall is segmented, so that the induction field penetrates through the slots (by inducing eddy currents into each finger segment) to melt the charge and at the same time repel the liquid metal away from the side wall to minimise the loss of superheat. A billet of TiAl alloy is loaded into the crucible before clamping on the ceramic shell mould. The mould is surrounded by a low thermal mass split-mould heater. After evacuating the vacuum chamber, the mould is heated to the required temperature (1200 °C maximum) and the vessel back-filled with argon to a partial pressure of 20 kPa prior to melting. This pressure significantly reduces the evaporative loss of the volatile aluminium contained in the alloy. The power applied to the induction coil is increased according to a pre-determined power vs. time schedule so that a reproducible final metal temperature is achieved. At the end of melting (7–8 min), the mould heater is opened and moved away. The induction melting power is rampeddown and, simultaneously, the ISM crucible and mould are rotated by 180° using a programmable controller to transfer the metal into the mould. The mould containing the casting is held vertically as the metal solidifies and cools down.3. Mathematical model3.1. Fluid flow equationsThe modelling of the castingprocess has involved a number of complex computational techniques since there are a range of physical interactions to account for: free surface fluid flow, turbulence, heat transfer and solidification, and so on. The fluid flow dynamics of the molten metal and the gas filling the rest of the space are governed by the Navier–Stokes equations, and a 3D model is used to solve the incompressible time-dependent flow:(1)(2)where u is the fluid velocity vector; ρ is the density; μ is the fluid viscosity; Su is a source term which contains body forces (such as gravitational force, a resistive force (Darcy term) [12]) and the influence of boundaries. There is a sharp, rapidly evolving, property interface separating metal and gas regions in these equations as explained below.3.2. Free surface: counter diffusion method (CDM)One of the difficulties of the simulation arises from the fact that two fluid media are present during filling: liquid metal and resident gas and their density ratio is as high as 10,000:1. Not only does the fluid flow problem need to be solved over the domain, but the model also has to track the evolution of the interface of the two media with time. A scalar fluid marker Φ was introduced to represent the metal volume fraction in a control volume and used to track the interface of the two fluids, called the Scalar Equation Algorithm (SEA) by Pericleous et al. [14]. In a gas cell, Φ = 0; in a metal cell, Φ = 1; for a partially filled cell Φ takes on an intermediate value which the interface of the two media crosses through. The dynamics of the interface are governed by the advection equation:(3)The interface then represents a moving property discontinuity in the domain, which has to be handled carefully to avoid numerical smearing. As in [14], an accurate explicit time stepping scheme such as that by Van Leer [15] may be used to prevent smearing. However, the scheme is then limited to extremely small time steps for stability, leading to very lengthy computations. To overcome this problem, a new tracking method, the counter diffusion method (CDM) [11] and [16], was developed as a corrective mechanism to counter this ‘numerical diffusion’. Thisdiscretizes the free surface equation in a stable, fully implicit scheme which makes the computations an order of magnitude faster. The implementation assumes that an interface-normal counter diffusion flux can be defined for each internal face of the computational mesh and applied with opposite signs to elements straddling the interface as source terms for the marker variable. The equation for the flux per unit area F can be written as:(4)where C is a scaling factor, a free parameter in CDM allowing the strength of the counter diffusion action to be adjusted, and n is the unit normal vector to the face in the mesh. Of the two cells either side of the face, the one w ith the lower value of the marker ΦD becomes the donor cell while the ‘richer’ cell ΦA is the acceptor (in order to achieve the counter diffusion action). The proposed formula makes the counter diffusion action self-limiting as it is reduced to zero where the donor approaches zero (gas) and where the acceptor reaches unity (liquid). In this form, the adjustment remains conservative. Quantitative validation of CDM against other VOF type techniques is given in a later section of the paper for accuracy and efficiency.3.3. Heat transfer and solidificationHeat transfer takes place between the metal, mould and gas, and between cold and hot metal regions as the mould filling is carried out. The heat flow is computed by a transient energy conservation equation:(5)where T is the temperature; k is the thermal conductivity; cp is the specific heat (properties can be functions of the local temperature or other variables); ST is the source term which represents viscous dissipation, boundary heat transfer and latent heat contributions when a phase change occurs. For the latter, a new marker variable fL is used to represent the liquid fraction of the metal with (1 − fL) being the volume fraction of solidified metal. V oller et al. [13] used a non-linear temperature function to calculate the liquid fraction. In this study, the liquid fraction is assumed to be a linear function of the metal temperature:(6)TL is the liquidus temperature and TS is the solidus temperature.3.4. LVEL turbulence model (applied to solid moving boundaries)Even at low filling speeds, the Reynolds number is such that the flow is turbulent. The LVEL method of Spalding [17] is chosen to compute the turbulence because of its mixing-length simplicity and robustness. LVEL is an abbreviation of a distance from the nearest wall (L) and the local velocity (VEL). The approximate wall distance is solved by the Eqs. (7) and (8):(7)∇·(∇W)=-1where W is an auxiliary variable in the regions occupied by the moving fluid with boundary conditions W = 0 on all solid walls.(8)This distance and the local velocity are used in the calculation of the local Reynolds number from which the local value of the turbulent viscosity νt is obtained using a universal non-dimensional velocity profile away from the wall. The effective turbulent viscosity is then computed from the following equation:(9)where κ = 0.417 is the von Karman constant, E = 8.6 is the logarithmic law constant [17] and u+ is determined implicitly from the local Reynolds number Reloc = uL/ν with the magnitude of the local velocity u and the laminar kinematic viscosity ν[17]. The LVEL method was extended to moving solid boundaries and in particular to solidifying regions by setting W = 0 in every region that is no longer fluid and then solving Eqs. (7) and (8) at each time step.In simulating the tilt-casting process, the geometry is kept stationary and the gravitational force vector is rotated to numerically model the tilt instead of varying the coordinates of the geometry. The rotating gravitational force vector appears in the source term of Eq. (1) for the tilt-casting process. A mathematical expression relating the tilting speed to the tilting angle θ has been used. Since θ is a function of time, the variable rotation speed is adjustable to achieve tranquil filling. This technique neglects rotational forces within the fluid (centrifugal, Coriolis) since they are negligible at the slow rotation rates encountered in tilt-casting. Finally, the numerical model of the tilt-casting process and the new algorithm developments were implemented in the general CFD package (PHYSICA).4. Description of simulations4.1. Geometry, mould design and computational meshThe casting is a generic 0.4 m-long turbine blade typical of that used in an Industrial Gas Turbine. Fig. 2 shows three mould designs which comprise the blade, a feeder/basin and a cylindrical crucible. Fig. 2a incorporates a separate cube-shaped feeder that partially links the root of the blade and the basin. Fig. 2b is a variant in which the plane of the blade is rotated through 90°. In both cases, the computational mesh contains 31,535 elements and 38,718 points. Six vents are located on the platform and the shroud of the blade, as seen in Fig. 2a and b. Fig. 2c is an optimised design where the feeder and basin are combined to provide a smooth connection between the blade and the crucible. Two vents are located in the last areas to be filled to help entrapped gas to escape from the mould. Mesh of the crucible-mould assembly for the three casesinvestigated.The mesh for the last case contains 30,185 elements and 37,680 vertices. As in all the cases presented, numerical accuracy depends on mesh fineness and also the degree of orthogonality. To ensure a mostly orthogonal mesh the various components of the assembly were created separately using a structured body-fitted mesh generator and then joined using a mixture of hexahedral and tetrahedral cells. The mesh was refined as necessary in thin sections (such as the blade itself or the shroud and base plates), but not necessarily to be fine enough to resolve boundary layer details. For this reason the LVEL turbulence model was used rather than a more usual two-equation model of turbulence that relies on accurate wall function representation. The practical necessity to run in parallel with the experimental programme also limited the size of the mesh used. As with all free surface tracking algorithms, the minimum cell size determines the time step size for the stable simulations. Although the CDM method is implicit, allowing the time step to exceed the cell CFL limit, accuracy is then affected. With these restrictions, turnaround time for a complete tilt-casting cycle was possible within 24 h.As stated earlier, the feeder is necessary to minimise the solidification shrinkage porosity in the blade root. Two alternative designs have been considered: a cubic feeder with a volume to cooling surface area ratio of 14.5 mm, and a cylindrical feeder designed with better consideration of fluid dynamics during mould filling and which had a slightly lower volume to area ratio of 13.8 mm.4.2. Initial and boundary conditionsThe choice of parameters for the calculations was based on the experiments [16]. The properties of the materials used in the calculations are listed in Table 1. The initial conditions (the same as in the trials) and boundary conditions of the calculations are shown in Table 2.Table 1.Properties of the materials in this study.Ti–46Al–8Ta alloy MouldDensity (kg/m3) 5000 2200Thermal conductivity (W/(m K)) 21.6 1.6Specific heat (J/(kg K)) 1000 1000Viscosity (kg/(m s)) 0.5 ×10−60.1Liquidus temperature (°C) 1612 –Solidus temperature (°C) 1537 –Latent heat (J/kg) 355,000 100,0004.3. Tilt cycleThe molten metal in the ISM crucible is poured via the basin/feeder into the mould by rotating the assembly. A parabolic programmed cycle [16] is employed to complete the castingprocess with a total filling time of 6 s. The carefully designed cycle includes a fast rotation speed at the early stage of the mould filling to transfer the molten metal into the basin/feeder, a subsequent deceleration to a nearly zero velocity to allow most of the metal to fill the mould horizontally and to avoid forming a back wave and surface turbulence, and then the rapid completion of the filling to reduce the heat loss to the mould wall.5. Computing requirementsThe results presented here have been obtained using an Inter (R) Xeon (R) CPU E5520 2.27 GHz, 23.9 GB of RAM. For a typical mesh of 30,000 finite volume cells, each full tilt-casting simulation (real time 6 s) took approximately 15 h and 1200 time steps to complete. The CDM algorithm uses a fixed time step of 0.005 s which is at least five times larger than that used in conventional methods such as Van Leer or Donor–Acceptor. Similar computations carried out with the alternative Donor–Acceptor algorithm took typically one week to complete.The speed of execution and stability of the CDM method does not necessarily compromise accuracy. This can be demonstrated in the classic collapsing column benchmark experiment of Martin and Moyce [18] shown schematically in Fig. 3. A rectangular water column with a height of 2 m and a width of 1 m is initially confined between two vertical walls in hydrostatic equilibrium. Air is present as the outer medium. Once the confining wall is removed, the water column collapses on to the plane y = 0 under gravity and spreads out along the x direction.Fig. 3. Configuration of water column collapsing experiment.View thumbnail images The experiment was designed specifically so that it could be modelled computationally in two dimensions. Therefore, a 2D domain was used meshed into 880 cells (40 × 22).The comparison between the numerical result with CDM, the Van Leer and the popular Donor–Acceptor algorithm against the experimental data is presented in Fig. 4, where the horizontal extent of the water front and the residual height of the water column are plotted as functions of elapsed time. It can be seen that there is generally good agreement between the numerical results and the experimental data. However, although the three numerical methods match each other perfectly, there is some disagreement against the experiment when the non-dimensional time t* is greater than 1.4. It is concluded that in terms of accuracy, CDM is at least as good as the alternative explicit techniques which have been in widespread use for many years.Fig. 4. Validation of the CDM method and comparisons of the CDM against Van Leer, and donor acceptor for (a) the front position and (b) the residual height of the collapsing water column experiment of Martin and Moyce [18].As mentioned above, a feature of the CDM method is that the discretization of the free surface equation is made in a stable, fully implicit scheme which makes the computations an order of magnitude faster. Table 3 presents a comparison of CDM against the other two methods investigated, in terms of the computational efficiency. It is shown that CDM can be applied with a bigger time step than the other methods since CDM it is not limited by the Courant–Friedrichs–Levy (CFL) criterion. Furthermore, due to greater numerical stability, the number of iterations per time step is also reduced which makes the CDM simulation even faster. The first two columns in the table show that the time step for CDM can be ten times bigger than the others. The running time with the Van Leer total variation diminishing (TVD) scheme is 1.3 times longer than with CDM for the same time step, but the Van Leer scheme suffers from interface smearing. The running time of the most popular scheme for casting simulations, the donor acceptor method, is almost four times longer than that with CDM when the same time step is used. CDM is up to eight times faster (16 s vs. 132 s as shown underlined in Table 3) when the optimal time step for CDM is used.Table 3. Comparisons of the efficiency of CDM with others numerical methods.Δt1 = 0.1 s Δt1 = 0.05 s Δt1 = 0.01 sMethodN t (s) N t (s) N t (s)Van Leer Error Exceeds CFL limit 10 47Donor Acceptor Error Exceeds CFL limit 40 132CDM 20 16 15 17 5 34Notes: Δt = time step; t = running time; N = average number of iterations per time step.6. Simulations – results and discussion6.1. Effect of mould orientationCalculations with two orientations (Fig. 2a and b) for the assembly with the cubic feeder have been performed. Fig. 5 shows the mould filling progression as iso-surface plots of the free surface marker, at Ф = 0.5, at a filling time of 3.2 s. It is seen that in a design without consideration for flow behaviour, the metal is thrown into the cubic feeder in both cases in a turbulent state, becauseof the sudden change in cross-section. At any given time during filling, more metal enters the cubic feeder and less enters the blade in orientation 2, Fig. 5b, compared with orientation 1, Fig. 5a, leading to a restricted exit path for the escaping gas. For both orientations, the sudden drop at the connection between the feeder and the root of the blade leads to jetting and turbulence at the point where the metal flows from the feeder into the blade cavity.Comparison of mould filling with two orientations in contour plots of the free surface marker Ф = 0.5 at the interface, time = 3.2 s for a cubic feeder: (a) orientation 1: mould oriented at 30° to tilt axis; (b) orientation 2: long axis of the root perpendicular to the tilt plane.A later stage in the filling process is presented in Fig. 6 for the same two orientations, with the blades now filled with metal. Although both orientations display the same problems of gas mixing and turbulence caused by the two sudden steps in the feeder, it seems that orientation 1 leads to less gas mixing than orientation 2. Fig. 7 shows the 0.4 m-long turbine blade castings produced by the process. There is surface evidence of porosity at the connection between the feeder and the root of the blade on the concave sides, and this is worse for orientation 2 than for orientation 1. Radiography indicates the internal extent of this porosity. Although several factors are responsible for its formation, including the presence of a hot spot leading to an isolated liquid pool during solidification and subsequent shrinkage, the presence of trapped gas is a major contributorComparison of mould filling with two orientations in contour plots of the free surface marker Ф = 0.5 at the interface, time = 5.2 s for a cubic feeder: (a) orientation 1: mould oriented at 30° to tilt axis; (b) orientation 2: long axis of the root perpendicular to the tilt plane.Comparisons of the experimental results with two orientations: (a) orientation 1: mould oriented at 30° to tilt axis; (b) orientation 2: root axis perpendicular to the tilt plane.6.2. Effect of the mould design: cubic vs. cylindrical feederIn the above discussion, it was shown that the orientation of the blade relative to the tilt axis in Fig.2 is important, and that the sudden changes in cross-section with a cubic feeder lead to turbulent mixing of gas and liquid metal. In the following section, the effect of the feeder design on casting quality will be studied comparing two mould designs: one with a cylindrical feeder (Fig. 2c) and the other with a cubic feeder with the preferred orientation (Fig. 2a).Fig. 8 shows a comparison of the instantaneous free surface location at a filling time of 3.0 s. As can be seen, the metal is smoothly entering the blade cavity in the case of the cylindrical feeder. In contrast the metal is thrown into the cubic feeder because of the sudden change in the cross-section. The sudden drop at the connection between the feeder and the root of the bladeleads to jetting and turbulence when the metal flows from the feeder into the blade cavity. The comparison also shows that the filling of the blade with the cylindrical feeder is faster than with the cubic feeder. This phenomenon is demonstrated in Fig. 9 as well.The comparison of the mould filling with the two designs of feeder: iso-surface plots of the free surface marker Ф = 0.5 at time = 3.0 s: (a) cube feeder; (b) cylindrical feeder.Comparison of the mould filling with the two feeders: contour plots with the free surface marker Ф = 0.5 at the interface, time = 4.6 s: (a) cubic feeder; (b) cylindrical feeder.9 shows the flow progress at a later stage of the mould filling (rotation time of 4.6 s) for the two competing designs. It can be seen that the design with the cylindrical feeder and with the vertical orientation of the blade provides a better gas escape route back to the crucible (in addition to gas escaping through the vents in the mould) than the design with the cubic feeder. There are two flow restrictions in the cubic feeder design: one is the connection between the basin and the feeder and the other is the connection between the feeder and the root of the blade, both leading to a step change in cross-section. This geometric feature of the assembly causes the gas to be easily trapped in the upper corner of the root.Fig. 10 highlights the velocity vector field as the metal enters the mould in the cubic feeder design, Fig. 2a. It is seen that the metal is pushed back from the root of the blade (zoomed). The metal and the gas re-circulate in the cavity of the root. This recirculation will result in mixing of gas with the metal which presents a high risk of forming casting defects such as bubblesFig. 10. The computed velocity field and iso-surface (free surface marker Ф = 0.5 at the interface) time = 3.1 s for the cubic feeder.The computed velocity field in Fig. 11a illustrates that the gas is trapped and gas recirculation takes place in the cube feeder although some gas in the aerofoil and in the platform is slowly evacuated by the vents at the platform of the blade (zoomed). Gas recirculation leads to gas–metal mixing. This introduces a high risk of the formation of gas bubbles which are then blocked inside the casting if the superheat is not high enough to allow them time to float up before the casting solidifies. In Fig. 11b, it is shown that the cross-section at the connection of the basin with the cubic feeder is fully blocked by the metal coming from the crucible at a certain moment during the mould filling. This is the reason that gas recirculation appears in the cube feeder and the root of the blade. For the cylindrical feeder, the gas evacuation path is clear (Fig. 11c and d) and there is no danger of the gas being trapped in the upper corner of the root, especially since a vent is located at the top of the platform (see Fig. 2). Comparison of the computed velocity field and iso-surface (free surface marker Ф = 0.5 at the interface) time = 4.8 s。

模具毕业设计论文外文翻译

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 holesand 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 .This member usually includes a mold-mounting pattern of boles or “T” slots.Tie rods are member of the clamping force actuating mechanism that serve as the tension member of the clamp when it is holding the mold closed.They also serve as a 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 o f 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 with temperature and p ressure.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 actuatingmachanism 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 more cavities,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 ,correct position relative tomachine nozzle .(2)Guide Pins-Maintain Proper alignment of entry into mold intrior .(3)Sprue Bushing(sprue)-Provide means of entry into mold interior .(4)Runners-Conrey molten plastic from sprue to cavities .(5)Gates-Control flow into cavities.(6)Cavity(female) and Force(male)-Contorl the size,shape and surface of moldarticle.(7)Water Channels-Control the temperature of mold surfaces to chill plastic torigid state.(8)Side (actuated by came,gears or hydraulic cylinders)-Form sideholes,slots,undercuts and threaded sections.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。

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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 holesand 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 .This member usually includes a mold-mounting pattern of boles or “T” slots.Tie rods are member of the clamping force actuating mechanism that serve as the tension member of the clamp when it is holding the mold closed.They also serve as a 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 with temperature 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 actuatingmachanism 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 more cavities,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 ,correct position relative tomachine nozzle .(2)Guide Pins-Maintain Proper alignment of entry into mold intrior .(3)Sprue Bushing(sprue)-Provide means of entry into mold interior .(4)Runners-Conrey molten plastic from sprue to cavities .(5)Gates-Control flow into cavities.(6)Cavity(female) and Force(male)-Contorl the size,shape and surface of moldarticle.(7)Water Channels-Control the temperature of mold surfaces to chill plastic torigid state.(8)Side (actuated by came,gears or hydraulic cylinders)-Form sideholes,slots,undercuts and threaded sections.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。