The appearance of metal gears has been around for many years and has been applied to various fields. Plastic gear appeared relatively late, but because of its many advantages, it has become more and more acceptable. The metal gear works well and has good dimensional stability when temperature and humidity change. But plastic gears also have many advantages in cost, design, processing, and performance.

From a molding perspective, the inherent design freedom of plastic molding ensures more efficient gear manufacturing. Products such as internal gears, gear sets, worm gears, etc. can be molded with plastics, but it is difficult to mold them with metal materials at a reasonable price. The application area of plastic gears is wider than that of metal gears, so they promote the development of gears to withstand higher loads and transmit more power. Plastic gears are also an important material that meets the requirements of low-quiet operation, which requires high-precision, new tooth profile, and materials with excellent lubricity or flexibility.

 

Plastic gears generally do not require secondary processing, so compared with stamped parts and machined metal gears, the cost is guaranteed to be reduced by 50%-90%. Plastic gears are lighter and more inert than metal gears and can be used in environments where metal gears are prone to corrosion and degradation, such as the control of water meters and chemical equipment.

Plastic gears can deflect and deform to absorb impact loads, and can better disperse local load changes caused by shaft deflection and misaligned teeth. The inherent lubrication characteristics of many plastics make them ideal gear materials for printers, toys, and other low-load operating mechanisms. Lubricants are not included here. In addition to operating in a dry environment, gears can also be lubricated with grease or oil.

Material reinforcement

In the description of gears and structural materials, the important role of fibers and fillers on the performance of resin materials should be considered. For example, when the acetal copolymer is filled with 25% short glass fiber (2mm or less) filler, its tensile strength increases by 2 times at high temperature, and its hardness increases by 3 times. The use of long glass fiber (10 mm or less) filler can improve the strength, creep resistance, dimensional stability, toughness, hardness, wear performance, etc. and other more properties. Because of the required hardness and good controllable thermal expansion performance, long glass fiber reinforced materials are becoming an attractive candidate for large-size gears and structural applications.