Injection Moulding Machinery

In Chapter 1, the basic parts of an injection moulding machine were identified as  

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Rothe, J. Improvements to injection moulding machinery. Kunststoffe German Plastics 1988, 78, 19-23. 

Deutsches IngenieurBlatt (For engineers in the construction industry) MM MaschinenMarkt Special Plastics (Injection moulding and mould construction, features specialist reports on injection moulding techniques (e.g. injection moulding machinery), special injection moulding processes (e.g. multi-component injection moulding), subsequent processes (e.g. surface treatment), injection mould construction (e.g. CAD/CAM systems, simulation) and other relevant topics)... 

This chapter begins with a breakdown of the purpose and the components of an injection unit. A glossary of common injection moulding machinery terms can be seen below. 

Machinery and processing conditions applicable to the injection moulding of PVC medical products have been examined (218). Details are also available of the design of an autoclavable PVC-P medical device which was injection moulded (178). 

The machinery for injection moulding of thermosets, because of the additional built-in facilities, is considerably more expensive than the conventional hydraulic press. However, advantages occur with the more precise and constant temperature controls and operating cycle which can be achieved with this machine. Many of the machines also have the advantage of being able, by the change of a cylinder and other ancillary equipment, to be used for injection moulding of thermoplastic materials. 

This section examines engineering and high performance polymers used in industrial applications. The applications covered are predominantly injection moulded parts for industrial equipment and machinery. The section also covers building and construction applications and mining. 

A review is presented of developments by a number of companies in rubber processing machinery, including injection moulding machines (with particular reference to presses for the processing of liquid silicone rubbers), extruders, mixers and calenders. 

Now that the basic machinery components have been discussed, the way in which injection moulding machines are designated can now be considered. Injection moulding machines are elassified by the machinery that they are composed of as set out in the International Standard. 

The Mono-Sandwich technique for co-injection moulding was described in Section 10.8.2.3 to which the reader should refer for machinery details. This technique can also be used for over-moulding by using the core back technique, again described earlier. In this technique termed the monosandwich 5 process, an additional valve is required in the runner system that ean release different valves as necessary . Once the melt is layered, the first component is injeeted. The valve is switched within the mould to expand the cavity and then the rest of the shot is injected to ereate a multi-shot component. 

For a bottle, the process is somewhat similar, except for the machinery which should be different, since the melted polymer is injected into a cold mould shaping the bottle. Thus the two polymers (or the three) are injected into the mould, in succession. The second polymer is injected while the surface of the previous one is still melted. 

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