专业英语大作业样本

lesson 10P1 P2The mould designer is frequently confronted with a component design that incorporates a recess or projection which prevents the simple removal of the molding from the mould. The mould design for this type of component is inevitably more complex than for the in line of draw component, as it necessitates the removal of that part of the impression which forms the undercut prior to ejection①.The splits can be incorporated in the mould design in several ways. The designer considers more complex systems where the splits are retained on the mould plate and actuated automatically. There are two basic designs: sliding and angled-lift splits. In both designs there are moving parts and it is necessary to arrange for (i) guiding the splits in the desired direction, (ii) actuating the splits, and (iii) securely locking the splits in position prior to the material being injection into the moul d②.模具设计师经常面临的一个组成部分的设计，包括凹槽或投影，防止简单去除成型模具。

因为脱模前要先抽出形成侧型芯的那部分型腔，这类零件的模具设计比直接脱模的零件复杂的多。

滑块可纳入模具设计的几种方法。

设计师认为，更复杂的系统，滑块将自动保留并驱动在模板中。

有两个个基本的设计思路：滑动和斜滑块。

在两者的设计中都有活动零件，而且有必要安排：沿着正确方向导向滑块，驱动滑块，在材料注射进模具之前安全地锁紧滑块。

Lesson 1The injection molding and machine1.1The injection molding2Injection molding is principally used for the production of the thermoplastic parts, although some progress has been made in developing a method for injection molding some thermosetting materials. The problem of injecting a melted plastic into a mold cavity from a reservoir of melted material has been extremely difficult to solve for thermosetting plastics which cure and harden under such conditions within a few minute s①. The principle of injection molding is quite similar to that of die-casting. The process consists of feeding a plastic compound in powdered or granular from a hopper through metering and melting stages and then injecting it into a mol d②. After a brief cooling period, the mold is opened and the solidified part ejected. Injection-molding machines can be arranged for manual operation, automatic single-cycle operation, and full automatic operation. The advantage of injection molding are: (i) a high molding speed adapted for mass production is possible; (ii) there is a wide choice of thermoplastic materials providing a variety of useful properties; (iii) it ispossible to mold threads, undercuts, side holes, and large thin sections.2.1注塑成型主要用于生产热塑性塑料配件，虽然已经取得了一些进展，在发展中国家的一些热固性材料注塑成型的方法。

问题的注射熔融塑料在模腔的熔融材料的容器已极难处理热固性塑料固化和硬化，在这种情况下，几分钟内①。

注塑成型原理很相似，压铸。

这个过程包括喂养塑料复合粉末或颗粒从料斗通过计量和融化阶段，然后注射到模具②。

经过短暂的冷却时间，打开模具和固化部分弹出。

注塑机可设置为手工操作，自动循环操作，全自动操作。

利用注射成型是：（一）高成形速度为适应大规模生产是可能的；（二）有多种可供选择的热塑性材料提供各种有用的性质；（三）是有可能的模具，削弱，侧孔，和大的薄片。

Lesson2 Mould for threaded components2.2 Stripping internal threadsThe internally thread component may be stripped from the core using the basic stripper plate design providing the plastic material has sufficient elasticity during the ejection phase②. The same principle applies here as to stripping any internal undercut, i.e. the molding must be free to expand during ejection to permit the molded undercut to ride over the restriction on the core③. This means that the outside form of the component must be such that it can be formed in a cavity which is fully contained in one half of the mould.Amould of this type is illustrated in Figure 2-1. This diagram shows a single impression mould for an internally threaded cap. The mould opens initially and, because of molding shrinkage and the undercut form, the molding is withdrawn from the cavity. During the latter stages of opening the stripper plate’s movement is checked, thereby causing the second opening to occur at B. The molding is, therefore, progressively stripped as the core is withdrawn through the stripper plate. The aperture in the stripper plate must be slightly larger in diameter than the major diameter of the thread in order to prevent scoring of the thread.内螺纹组件可能被剥夺的核心采用推板设计提供塑料材料有足够的弹性在弹射阶段②。

同样的原则适用于这里作为剥离的任何内部削弱，即成型必须自由扩大在弹射允许成型凹穴通过限制的核心③。

这意味着，外部组件形式必须是这样的：它可以形成一个腔是完全包含在一个半的模具。

模具这种类型是说明了在图2 - 1。

这个图显示了一个单一的印象模具内螺纹帽。

模具打开了最初，因为成型收缩和削弱形式，成型退出腔。

在后期的开放料板检查，从而造成二开口发生在B成型，因此，逐步剥离为核心撤回通过卸料板。

光圈在料板必须稍微比直径大的大直为防止得分线。

Lesson 3 Basic underfeed mouldP1 P2 P3The moving half consists of the moving mould plate assembly, support blocks, backing plate, ejector assembly and the pin ejection system. Thus the moving half in this design is identical with the moving half of basic moulds.The floating cavity plate, which may be of the integer or insert-bolster design, is located on substantial guide pillars (not shown) fitted in the feed plate. These guide pillars must be of sufficient length to support the floating cavity plate over its full movement and still project to perform the function of alignment between the cavity and core when the mould is being close d. Guide bushes are fitted into the moving mould plate and the floating cavity plate respectively.The maximum movement of the floating cavity plate is controlled by stop bolts or similar devices. The moving mould plate is suitably bored to provide a clearance for the stop bolt assembly. The stop bolts must be long enough to provide sufficient space between the feed plate and the floating cavity plate for easy removal of the feed system. The minimum space provided for should be 65mm just sufficient for an operator to remove the feed system by hand if necessary.一个简单的模具，这种类型是显示在图3 - 1，并说明设计和开放序列如下。