How to Design Plastic Gears That Operate Efficiently

Plastic gear is a type of gear that is used in a wide range of industrial applications. They are a popular choice for manufacturers because of their versatility, as they can be used in a wide variety of configurations and shapes. They also offer a number of advantages over traditional metal gears, including reduced costs and weight.

Plastics are manufactured from byproducts of petroleum production, which makes them a cost-effective alternative to metal gears that require more energy and effort to shape and manipulate. Additionally, many types of plastics are self-lubricating, which eliminates the need for additional lubrication. This allows them to be used in applications that would normally require a lot of maintenance or that could cause a lot of noise.

In terms of power transmission, plastic gears have the potential to be more efficient than metal gears due to their lower coefficient of friction. They can also be made in a larger diameter than their metal counterparts, which can increase their load-carrying capacity. However, in order to ensure that plastic gears operate efficiently, proper design and manufacturing processes must be followed.

The most important factor to consider when designing a plastic gear is the material used to make it. This is because the different types of engineering plastics have a vastly different coefficient of thermal expansion, density, and modulus of elasticity. In addition, each resin has its own set of morphological properties that influence its mechanical behavior. For this reason, it is critical to use a polymer that has been designed specifically for gearing applications.

There are two main types of plastics commonly used for gear production: Polyamide (Nylon) and Acetal copolymer. Nylon and acetal are both very strong materials, which can be molded into complex, intricate shapes. They are very resistant to corrosion and can withstand extreme temperatures. In addition, these plastics are typically self-lubricating, which eliminates a lot of the maintenance and trouble that comes with maintaining a metal gear system.

Regardless of the type of plastic used, it is essential to avoid sharp corners and sudden changes in cross section in the gear teeth. This will help to minimize stress concentration and increase the gear’s life expectancy. It is also necessary to provide adequate space for fasteners, such as set screws, to be inserted into the bore. This will allow for proper torque transfer and prevent the gear from deforming or failing during operation.

Another consideration when choosing a plastic gear is its dimensional stability. It is important to have a stable gear, which can be achieved by annealing the finished part after molding. This step helps to relieve residual stresses that may be caused by the injection molding process.

Finally, plastic gears can be fabricated to extremely high levels of accuracy. For example, Hewlett-Packard and molder UFE used acetal cluster gears in their DeskJet 660 color printer to achieve AGMA quality class Q9. This high level of accuracy is needed to ensure that the printer can print consistently without skipping or overprinting lines.