5 Benefits of Plastic Gears
Plastic gears are used in a range of applications, such as food production machines, consumer electronics and medical equipment. Due to plastic gear materials, they offer a rust-proof and lightweight solution compared to other gear types. There are a host of beneficial properties that set plastic gears apart.
Low-Cost Plastic Gears
Plastic gears are generally cheaper to produce than metal gears, and therefore cheaper to buy. The manufacturing processes involved in producing plastic gears often require fewer secondary finishing steps compared to metal gears, making it more cost effective. Plastic materials are also generally less expensive than metals.
Choice of Plastic Gear Materials
Plastic gears are typically made from one of two materials: POM (polyoxymethylene, also known as acetal or the trade name Duracon) or MC nylon, a polyamide resin. Gears manufactured using POM can be made by pouring melted resin into a mold and applying pressure (injection molding). Meanwhile, MC nylon gears are made by gear cutting.
Though it depends on the environment, MC nylon typically absorbs water 10 times more than POM does. Absorbing water lowers dimensional accuracy and consequently produces noise or lowers the transmission efficiency of torque. Additionally, a deterioration of resin occurs due to hydrolysis, therefore POM is a more suitable material for gears that are going to be used in high humidity or wet environments.
On the other hand, MC nylon is better in terms of mechanical properties because of the tensile strength and bending strength. For instance, the bending strength of MC nylon is 1.2 times stronger than POM. As a plastic gear, MC nylon is more suitable when a large force is applied.
Less Lubrication Required for Plastic Gears
Due to the materials that plastic gears are made from, they are smooth and, in many cases, do not require lubrication with oil unlike metal gears. However, plastic is a softer material than metal and is, therefore, prone to incurring damage on the tooth surface due friction – so, in some instances lubrication should be considered.
How should plastic gears be lubricated?
Plastic has a characteristic of deteriorating with oil. For lubricating plastic gears, an oil that does not have polarity is the ideal choice (polarity means having different properties in a molecule) such as synthetic hydrocarbon oils. Synthetic hydrocarbon oils are chemically modified to achieve specific performance characteristics, like superior lubrication at high or low temperatures.
Plastic Gears Offer Lightweight Solution
Plastic gears are generally lighter than their metal counterparts. Gears made from POM or nylon have lower densities compared to metals like steel, for example, meaning they weigh less for the same shape and size. This results in less inertia in the gear system and lower assembly weight.
Rust-Free Plastic Gears
Certain metals offer more corrosion resistance than others, with surface treatments available to help prevent corrosion or rust. Plastic gears are completely corrosion resistant, meaning that they can work in moist environments without the risk of rusting. There is no need for additional treatments.
Summary
Plastic gears have a range of benefits that make them worth considering for design engineers and manufacturers. For industries looking for a lightweight, low-cost alternative to metal gears – plastic gears are the optimal solution.
There are a range of high-quality plastic gears from Japanese manufacturer KHK, available from our online gear shop. KHK offers: plastic spur gears, plastic spur gears with steel core, plastic racks, plastic miter gears, plastic bevel gears, plastic screw gears and plastic worm wheels. The gears are made from nylon and POM.
