Plastic sprockets are gaining popularity in many industries and applications because they offer a number of advantages over metal alloy sprockets, especially in food industry applications. Plastic sprockets and elsewhere are becoming a safe and cost-effective alternative because they resist corrosion from oxidation and chemical contract, reduce excessive chain or belt wear, require no lubrication, do not cause static and other electrical charge issues, offer a low coefficient of friction, are light weight, operate quietly, and come in a wide range of USDA/FDA-approved compounds.
Plastic sprockets are widely accepted for use in applications such as food processing, packaging, bottling, wood processing, and waste water treatment. Plastic sprockets are readily available in a variety of sizes, styles, and plastic materials from Slideways. Because the individual characteristics vary from compound to compound, it’s important to choose the right material for your specific plastic sprockets application and environment.
Here are some common, popular plastic sprocket plastics and their major attributes:
Ultra-high-molecular-weight-polyurethane has a very low coefficient of friction, outstanding impact strength, and excellent abrasion resistance. UHMW-PE is well-suited for moderate-load plastic sprockets and offers good chemical resistance. This material is USDA/FDA approved.
This type of nylon has a low coefficient of friction, good impact and abrasion resistance, and good chemical resistance. Because it is rigid, it resists creep and distortion of sprocket keyways under high loads. Plastic sprockets made from oil-filled nylon include those used with roller chain and flat top chain.
This nylon material contains glass fibers, usually added during injection molding, to increase its rigidity for high-load applications. Roller chain plastic sprockets are often made from glass-filled nylon.
Polypropylene offers balanced thermal, chemical, and electrical properties. It, too, has a low coefficient of friction, as well as fair impact and abrasion resistance. Polypropylene plastic sprockets and elsewhere are typically used in chemically harsh environments because they resist attack by most organic chemicals, mineral acids, and gases.
Because of its high cost, PTFE is not typically used for plastic sprockets. However, it offers a very low coefficient of friction and easily operates in a wide temperature range. It has excellent chemical resistance, but only fair impact and abrasion resistance.
For close-tolerance applications, acetal is an excellent choice for plastic sprockets. It machines well and has a low coefficient of friction. It is often used to make small roller chain or custom sprockets. Acetal is a hard material that resists creep, but it tends to be brittle and has only fair abrasion resistance.