Methods for making plastics gears

Plastics gears can be manufactured in a number of different ways, which may be listed as follows. 

Gears are made using conventional machine-cutting techniques, from rod, tube or sheet/plate of the required plastics materials. Examples are nylon, acetal and polyethylene materials (ref. 1). The rod, tube and plate may be manufactured from raw polymer by extrusion or (for certain nylon grades) 

Moulded gears, however, are our main concern in this study. The most important process, and the one with which we are concerned here, is injection moulding of thermoplastic polymers. Later sections will deal with details of the process and the materials commonly used. 

A less-important process is compression moulding of thermosetting resin compounds. These are often phenol-formaldehyde resins reinforced with fibrous fillers. 

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