5. Implementation and applications

5.1 Injection

A distinction can be made between:

• single injection;

• bimaterial injection molding, which produces parts with a skin that gives them their appearance and characteristics, and a core made from lightweight or recycled materials;

• co-injection of gas into HDPE, which has a number of advantages: lighter hollow parts, less shrinkage, better surface appearance, less distortion, lower internal stresses, reduced clamping force and shorter cooling time; but also disadvantages: impossible to use a multi-cavity mold, hole – to be plugged – in the part at...