机电技术专业英语 教学课件 作者 徐起贺 张庆良pata b lesson Fifteen.pptVIP

* 机电技术专业英语 Lesson Fifteen Text Mould is a fundamental technological device for industrial production. Industrially produced goods are formed in moulds which are designed and built specially for them. The mould is the core part of manufacturing process because its cavity gives its shape. There are many kinds of mould, such as casting forging dies, ceramic moulds, diecasting moulds, drawing dies, injection moulds, glass moulds, magnetic moulds, metal extruding moulds, plastic and rubber moulds, plastic extruding moulds, powder metallurgical moulds, compressing moulds, etc. The following is the introduction of some of the moulding process and the corresponding moulds used. Introduction to Mould Lesson Fifteen Compression Moulding Compression moulding is the least complex of the moulding processes and is ideal for large parts or lowquantity production. For lowquantity requirements it is more economical to build a compression mould than an injection mould. Compression moulds are often used for prototyping, where samples are needed for testing fit and forming into assemblies. This allows for further design modification before building an injection mould for highquantity production. Compression moulding is best suited for designs where tight tolerances are not required. A compression mould is simply two plates with cavities cut into either one or both plates. Additional plates between the top and bottom plates can be included to create cavities in the moulded part. Figure B.15 shown below is an example of a basic twoplate single cavity mold. The mould does not require heater elements or temperature controllers. The moulding temperature is fully controlled by the pressure it is running in. Lesson Fifteen Figure B.15 A compression mould 1. top plate； 2. opening bar slot； 3. handle； 4. dowel pin bushing；5. flash tear trim gate； 6. part cavity； 7. bottom plate Due to the simplicity of the mould, it is the most economical mould to buy. And