Description

Plastic and rubber balls are rolling, spherical elements that have low friction values and require little or no lubrication. They are lighter than metal balls and resistant corrosion and abrasion. Some plastic balls resist high temperatures, but others do not. Rubber balls are characterized by a high degree of flexibility and elasticity.

Types

The GlobalSpec SpecSearch database characterizes plastic and rubber balls by material type.

• Acetal balls are recommended for applications where low water absorption is required. Acetal is similar to nylon, but slightly harder and denser.
• Acrylic balls have high resistance to heat distortion and good tensile strength. They have a highly polished finish and good optical qualities.
• High-density polyethylene (HDPE) balls resist stress cracking better than low-density polyethylene (LDPE), which is softer and lightweight.
• Nylon balls are used in check valves, light load bearings, knobs, toggle switches, and other applications where cost is more important than hardness. Nylon exhibits good resistance to alkalis, petroleum products, and mild chemicals.
• Polyamide balls and polyimide balls are used in bearing and wear applications. They exhibit better heat resistance than many other plastic balls, and also exhibit high strength, dimensional stability, and impact resistance.
• Polypropylene balls resist corrosion and water absorption, and are characterized by their low weight. They are used in fluid level gauges, flow meters, valves, and vapor and evaporation shields for electrolytic solutions.
• Polyurethane balls provide good sealing at low pressures in non-return valves. Polyurethane offers excellent wear resistance, but is not recommended for use with acids and alkalis. 
• Polytetrafluoroethylene (PTFE) balls resistant most corrosive agents and are electrically nonconductive. They are also used in systems that handle cryogenic liquids and acids.

In addition to material types, plastic and rubber balls are characterized by grade, tolerance, and sphericity.

Applications

Plastic and rubber balls are used in many different industrial applications and equipment. Screen balls are used in screeners, separators and sieving machines to deblind or knock up screen or sieve openings plugged with particulates or powder particles. Screen balls typical consist of rubber or plastic materials because these materials can absorb impacts without prematurely wearing out metal screens or cloth sieves.

References

Salem Specialty Ball Company – Plastic Balls