Another reason which may not be apparent is the reduction of friction between the molecules of the plastic materials.
Plastic on plastic lubricant.
Standard petroleum based lubricants cannot be used for plastic gears and some plastic gears are designed to be used without lubricants.
As with all things silicone has its dark side.
This quick study contains tips that will help you choose the best lubricant for your plastic part with special notes on gears.
Because silicone oil is super slippery and minimally reactive it can lubricate most anything.
Machinery parts and components made from plastic can be an easier and more cost effective alternative to traditional metal parts for some applications.
Lubricants are used in plastics mainly to reduce friction between the processing machinery and the plastic materials.
Incompatible plastic lubricant combinations often cause operating problems such as stress cracking or failure of the plastic component.
Similar to metal components proper lubrication can extend the operating life and efficiency beyond using no lubricant at all.
Table 1 gives general compatibility guidelines.
Some plastic gears can be embedded with lubricating materials such as ptfe silicone or graphite.