《模具毕业设计论文外文翻译.docx》由会员分享，可在线阅读，更多相关《模具毕业设计论文外文翻译.docx（8页珍藏版）》请在taowenge.com淘文阁网|工程机械CAD图纸|机械工程制图|CAD装配图下载|SolidWorks_CaTia_CAD_UG_PROE_设计图分享下载上搜索。
1、模具毕业设计论文外文翻译 and moldmounting pattern of blot holes or “ T”slots .Stationary plate is the fixed member of the clamping unit on which the stationary section of the mold is bolted .This member usually includes a mold-mounting pattern of boles or “ T” slots.Tie rods are member of the cla mping force ac
2、tuati ng mecha nism that serve as the tension member of the cla mp whe n it is holdi ng the mold closed.They also serve as a gutde member for the movable plate .Ejector is a pro visi on in the cla mping unit that actuates a mecha nism within the mold to eject the molded p art(s) from the mold .The e
3、jecti on actuat ing force may be app lied hydraulically or pn eumatically by a cyli nder(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 con sta ntly being imp rored .c
4、ouve nti onal machi nes use a cyli nder and p ist on to do both jobs .This method simp lifies mach ine con struct ion but makes con trol of injectio n temp eratures and p ressures an in here ntly difficult p roblem .Other machi nes use a p lastcat ing extruder to melt the p lastic and p isto n to in
5、ject it while some hare bee n desig ned to use a screw for both jobs :Nowadays,sixty p erce nt of the mach ines use a rec ip rocati ng screw,35% a plun ger (concen trated in the smaller machi ne size),a nd 5%a screw pot. Many of the problems connected with in jection molding arises because the densi
6、ties of polymers change so markedly with temperature and pressure.Athigh temp eratures,the den sity of a polymer is considerably cower than at room temp erature ,p rovided the pressure is the same.Therefore,if modls were filled at atmos pheric p ressure, “shrinkage ” would make the molding deviate f
7、orm the shape of the mold. To compen sate for this poor effect, molds are filled at high p ressure.The p ressure comp resses the poly mer and allows more materials to flow into the mold,shri nkage is reduced and better quality moldi ngs are p roduced.Cludes a mold-m oun ti ng p attern of bolt holes
8、or “ T”slots.Tie rods are members of the clamping force actuating macha nism that serve as the tension members of cla mp whe n it is hold ing the mold closed.Ejector is a pro visi on in the clami ng unit that actuates a mecha nism within the mold to eject themolded p art(s) form the mold.The ejectio
9、 n actuati ng force may be applied hydraulically or pneumatically by a cylinder(s) attached to the moving pl ate,or mecha ni cally by the opening stroke of the moving p late. The fun ctio n of a mold is twofold :im parti ng the desired sha pe to the p lasticized poly mer and cooli ng the injectio n
10、molded p art.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 p arts :(1) a statio nary molds half one the side where the p lastic is injected,(2)Am
11、oving half on the clos ing or ejector side of the mach ine. The sep aratio n betwee n the two mold halves is called the parting line n some cases the cavity is partly in the statio nary and p artly in the moving secti on. The size and weight of the molded p arts limit the nu mber of cavities in the
12、mold and also determ ine the mach inery cap acity required.The mold components and their functions are as followi ng : Mold Base-Hold cavity(cavities) in fixed ,correct position relative to mach ine no zzle . Guide Pin s-Ma in tai n Proper alig nment of en try into mold in trior . Sprue Bush in g(s
13、prue)-Pro vide mea ns of entry into mold in terior . Runn ers-C onrey molte n p lastic from sprue to cavities . Gates-Co ntrol flow into cavities. Cavity(female) and Force(male)-C on torl the size,sha pe and surface of mold article. Water Cha nn els-Co ntrol the temp erature of mold surfaces to chil
14、l p lastic to rigid state. Side (actuated by came,gears or hydraulic cylinders)-Form side holes,slots, un dercuts and threaded sect ions. 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。溶 里在模腔里冷却，硬化，直至完 全固
15、化。然后将模子打开，推出工件，并重复以上工序。 (1) (8) 因此，注塑成型机的重要组成部分是：1）将溶体塑化并挤进进模腔（称做“注塑单元”）；2）开模和加压合模统称为“合模系统”）； 3）使用上下模具；4）机器控制。 注射装置通过家热将固态塑料转化成均匀的半液态塑体。它保持塑料当前温度并加压使之通过喷嘴进入模具。柱塞集塑化和注射为一体。在柱塞与模具之间没有加热室，几热室通过热传导加热塑料。每次行程，柱塞将待熔化塑料推入加热室，依次将熔化的塑料挤到加热室前端并通过喷嘴注射出去（注射到模具中去） 合模装置是注射成型机的一个部分，该装置上安装有模具。合模装置提供运动和动力以开模几合模，并且在注射
16、过程中提供压力保持模具紧闭同时，该装置还提供成型工艺有效运动所必需的其它特性。动模板是合模装置的一部分，在合模时向定模板移动。型腔的运动部分用螺栓固定在动模板上，动模板通常动模板通常含顶出杆，螺栓空或T型槽的安装模具的型板。拉杆是合模力驱动机构中的一个构件，当夹具保持动模闭合时，拉杆起夹具的拉力构件的作用。顶出器是合模装置的一个部件，它驱动模具中的执行机构从模具中顶出成型制品。顶出力可由液压或气动装置通过装在动模板上的油（气）缸来施加，或者通过动模板开模行程来施加。 塑料熔融与塑料注射的方式随机器的不同而不同，并不断得以改 善。常规的机器采用一个料筒和一个活塞来进行熔融和注射。 虽然这 种方式
17、简化了机器的结构，但却使注射的温度和压力控制成了一个固 有的难题。有的机器用一个塑化挤压器来熔化塑料， 用一个活塞进行 注射。另外，还有一些已设计出来的机器采用一个螺杆来完成熔融和 注射。目前，百分之六十的机器采用往复式螺杆，百分之三十五的机 器采用柱塞；百分之六十的机器采用螺罐。 聚合物的密度在不同的温度和压力下变化很大，并由此产生了注 射成型的许多问题。在压力不变的情况下，在高温下的聚合物的密度 比在低温下的要低得多，因此，如果在大气压下向模子充模，成型件 回因“收缩”而与模子的形状形成偏差。 为了补偿这一偏差，模子充料在高压下进行。高压压缩了聚合物 并能使更多的材料流入模腔。这样，“收缩
18、”就减少了，生产的成型 件的质量就得以提高。 模具的功能有两方面：一是使可塑聚合物按希望的形状成型， 而 是使其冷却定型。注射模具基本由两套部件组成：型腔和型芯，安装 型腔和型芯的模板。具有一个型腔或多个型腔的模具由两个基本部分 组成：（1）注射塑料一侧的定模（2）闭合及顶出机器一侧的动模。 两哈夫对开的定模、动模分界线叫做分型面。有时，型腔一部分在定 模中，一部分在动模中。塑料成型制品的尺寸和重量限制了一副模具 中型腔的数目， 及其功能如下： 模板一保持型腔相对注射机床的喷嘴具有固定、正 确的位置。 导柱一保持定模、动模哈夫在合模时具有正确的相 对位置。 主流道衬套一提供熔融塑料流入模具内部的通道。 流道一将容忍塑料从浇注口传送到各型腔。 浇口一控制熔融塑料流入型腔。 凹模（阴模）和凸模邙日模）一控制成型塑料制品 的尺寸、形状及 表面纹理。 冷却水道一控制模具表面温度，使塑料制品冷固成 型。 侧板（由凸轮、齿轮或液压油缸驱动）一形成制品 的侧孔、侧槽、 侧凹螺纹部分。 并且取得了所需的注射机床生产能力。 模具的零部件 (7)