Urethane Wheels
Urethane wheels are fabricated from molded urethane, technically referred to as polyurethane (or PU), which is an elastic polymer, or elastomer, containing urethane carbamate links. Urethane wheels combine many of the desirable qualities of plastic, rubber and metal wheels with longer service life than plastic wheels and higher impact resistance than rubber wheels. Other unique properties to molded urethane include elastic memory, noise reduction, heat and chemical resistance, and durability. Urethane wheels can be fabricated to be sponge-soft or iron-hard in a wide range of sizes, shapes and colors. Applications for urethane wheels include forklift drive and load wheels, rollercoaster wheels, skateboard wheels, conveyor bearings, grocery carts and carrying case wheels. These polyurethane wheel applications and more benefit industries such as material handling, industrial manufacturing, retail, transportation, athletic equipment and medical.
Urethane wheels are made through two main processes: liquid casting, meaning that urethane is melted down to a liquid form and then poured into a wheel-shaped mold to be cooled into a solid form; and injected molding, meaning that urethane is melted down to a liquid from and injected into a wheel-shaped mold through fill holes using a low-pressure pneumatic injection gun. Secondary machining processes can also be used to form urethane wheels from molded urethane. Urethane wheels can consist of solid urethane or of urethane bonded to metals such as steel, aluminum and cast iron for heavy duty applications. When bonded to metals, urethane serves as the tread of the wheel and the metal serves as the core. Different types of urethane wheels include: crowned wheels, generally used for turns in conveyor systems; engraved wheel, typically engraved with identifying marks such as parts numbers or brand names; deskew wheels, primarily used in document processing equipment; drive wheels, which offer excellent abrasion resistance for industrial machines; and compliant wheels, which are used for document processing when the documents are of varying thicknesses.
Urethane wheels possess several advantages over metal, plastic and rubber wheels in many applications. Urethane wheels have an advantage over rubber wheels due to a higher impact resistance, broader hardness range and better colorability. As compared to metal wheels, urethane wheels have better noise reduction and resilience, greater abrasion, corrosion and impact resistance, more flexibility and are less costly to fabricate. Urethane wheels function better than regular plastic wheels in many applications because they have higher impact resistance, low temperature, cold flow, radiation and abrasion resistance, better elastic memory and noise reduction capabilities, greater resilience and provide lower cost tooling. The cost of fabricating urethane wheels is on par with the cost of rubber and typical polymer molding, giving urethane an economic advantage as well. Molded urethane is also an FDA-approved material for clean room environments, giving urethane wheel manufacturers a competitive edge in the medical industry since it is conducive to hygienic environments.