Solid rubber casters are soft, and therefore make a minimal amount of noise. But don’t mistake “soft” for “weak.” Rubber casters are actually ideal for heavy duty use such as for shopping carts and industrial equipment.
Some advantages to rubber casters include:
Low noise properties
Perfect for rough terrain
No damage to floors
How Rubber Casters Are Made
Solid natural rubber casters are made from latex that comes form the Hevea Basiliensis tree. Synthetic rubber casters are made from byproduct chemicals produced from the petroleum refining process.
Many different types of rubber exist. Although they mostly look identical, different rubbers have different properties. Choosing the right one for your needs is crucial.
Black Rubber Casters: Standard black rubber casters are typically a mixture of natural and synthetic styrenebutadiene (SBR) rubber. These are used for industrial wheels, and are best suited for industrial equipment.
SBR Castors: SBR castors have formulations similar to automobile tires. In order to attain the needed properties of wear resistance, tensile strength, and flexibility, rubber mixture must be combined with different fillers and chemicals. The mixture is called a compound.
A rubber compound usually contains about 50 to 60% natural rubber, carbon black particles, and different chemicals that give the compound strength and resistance to sunlight and the elements. In order to help the processing along, the manufacturer may use manufacturing method oil, as well as sulphur to vulcanize the mixture.
After the compound is complete, it’s ready for the molding process. Most casters and tires are created using the compression molding method. This is a simple technique where the manufacturer creates a molding tool to the dimensions of the wheel. The compond is then placed in the mold along with the wheel hub which has been covered by adhesive. The mold is then closed and held pressure by a heated press, allowing the rubber to form into the shape of the caster tire. The mold is then opened and the finished caster is removed.