Design of moulded gears

The detailed design calculations for the office-copier gearbox are confidential, and are not included in this study. The section therefore deals with the principles of design for injection-moulded gears (ref. 2). 

The design considerations for moulded gears can be listed under two headings  

In achieving a successful overall design these two aspects must be combined, to give a product that works well, and which can be easily and efficiently moulded. 

Gears usually fail by fatigue, following repeated cyclic stressing, and 

Another important failure mode is environmental stress cracking (ESC), and it must always be borne in mind for plastics gears. 

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