Plastic Spur Gears

Plastic gearing has been increasing in usage as designers better understand their benefits and limitations. These gears can be produced by hobbing or stamping or, for large-volume runs, by injection molding. Some of the key benefits of plastics in the production of gearing are:

Reduced weight and lower inertia due to the lower density of the material

Ability to absorb shock and vibration due to the elasticity of the material.

Reduced noise.

Low coefficient of friction

Self-lubricating in most cases.

Able to be used in wet environments and food preparation areas.

However, as with all materials, there are also some drawbacks to using plastic materials in gears. These include:

Less load-carrying capacity compared to similarly sized metal gears.

Molded gears cannot hold the same high tolerances that metal gears can.

Plastic is less dimensionally stable when compared to metal and this results in dimensional variations due to temperature and humidity conditions.

Material cost is significantly higher than that of base metals and can vary widely due to fluctuations in the cost of base chemicals.

Difficulty in attaching plastic gears to metal shafts.