Compared to metal forming, the inherent design flexibility of plastic forming ensures more efficient gear manufacturing. Products like internal gears, gear sets, and worm gears can be made using plastic forming, which is difficult to achieve at a reasonable cost with metal materials. Injection molded gears have a broader application field than metal gears, thus driving the development of gears towards bearing higher loads and transmitting greater power.
Injection molded gears are also an important material to meet the requirements of low-noise operation, which calls for the advent of high-precision, new tooth profiles, and materials with excellent lubricity or flexibility.
Injection molded gears generally do not require secondary processing, thus ensuring a cost reduction of 50% to 90% compared to stamped and mechanically manufactured metal gears. Injection molded 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 water meters and chemical equipment controls.
Compared to metal gears, injection molded gears can deflect and deform to absorb the impact load, better dispersing the local load changes caused by shaft misalignment and tooth errors. Many plastics' inherent lubricating properties make them ideal gear materials for printers, toys, and other low-load operating mechanisms, excluding lubricants. In addition to running in dry environments, gears can also be lubricated with grease or oil.
The production process of injection molded gears includes the following major steps:
Mold Design and Manufacturing
First, design the mold according to the gear's design requirements (such as tooth profile, size, module, number of teeth, etc.).
Injection Process
In the injection molding process, the plastic raw material is heated to a certain temperature until it melts into a liquid state, and then injected into the gear mold cavity through an injection molding machine. The cooling system in the mold quickly cools the hot plastic, solidifying it into the shape of the gear.
Demolding and Post-Processing
After injection molding, the gear is removed from the mold. At this time, the gear surface may need to undergo post-processing procedures such as deburring, grinding, and spraying to improve its appearance and precision. Some gears may also undergo heat treatment or other surface treatments to enhance their wear resistance and service life.
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