While metal gears have long been the primary material for industrial machinery and equipment, plastic gear is quickly gaining in popularity. The quiet operation of these lightweight components, along with their chemical resistance and low coefficient of friction, make them ideal for a wide range of applications. Choosing the right plastic gear for your application is critical, and it’s important to understand how these components are made.
Several types of plastics are used for gearing, including unfilled nylon and acetal. Other materials are also available, such as linear polyphenylene sulfides and long fiber plastics. Each type of plastic has its own unique characteristics that can be exploited in different applications.
The most common method of manufacturing plastic gear is injection molding, where the resin of choice is heated to a melting point and then injected into a mold. The molded product is then cooled and solidified before being ejected from the mold and any finishing work is performed. Injection molding is the most economical and versatile process for making plastic gears, and it can be used to create parts with complex designs that would be difficult or costly to produce using other methods.
A wide range of gears are produced using this method, from small household appliances to massive machinery. Plastic gears are commonly found in vehicles, such as power steering and electric start-stop motors, to reduce vehicle weight and cost and improve fuel efficiency. They can also be found in many other pieces of production equipment, such as food processing machines and medical equipment.
Plastic gears are generally easier to manufacture than metal ones, and they are less likely to rust or corrode. They are also more resistant to high temperatures and chemical exposure than metals, and they can withstand heavy loads without losing their form. Additionally, plastics can be shaped into an infinite number of designs, which gives manufacturers more options when creating the final product.
To achieve the best performance out of plastic gears, they must be properly sized and designed. In general, the larger the tooth, the more efficient it is. However, too large a tooth can suffer from mechanical interference due to excessive compliance.
Another important factor in designing plastic gears is ensuring the proper lubrication of the teeth. A lubricant should be viscous enough to form an oil film between the teeth and keep them separate, yet thin enough to prevent leakage. The lubricant should also be able to penetrate into small recessed areas and not squeeze out when subjected to stress.
The maximum load carrying capacity of plastic gears decreases with temperature, but this is much less pronounced than for metal gears. Therefore, it is important to choose a lubricant that can withstand the highest operating temperatures. In addition, the lubricant must be easily washable so that it can be removed and replaced as necessary. Fortunately, many types of lubricants are suitable for use with plastic gears.