Precision Plastic Balls are manufactured from thermoplastic and thermosetting plastic materials and elastomers in a wide range of sizes depending on material type. A list showing the current range of sizes/materials is given at the technical page which is under continuous review and extension.
Plastic materials are relatively light, having a specific gravity ranging from around 0.90 to 2.14 g/cc. They have a low modulus of elasticity which can assist in reducing noise levels, are rust proof and have good resistance to corrosion and attack from a wide range of chemicals.
Plastic Balls have good electrical insulation properties, are self lubricating and are non-magnetic.
The production method
Once the balls have been formed they are fine ground and lapped and sometimes tumble polished to a finished diameter – final tolerances are dependent on size and material type.
The low modulus of elasticity of plastic materials reduces the need for finer tolerances associated with metal balls.
When using Plastic Balls in non-return valves, it is essential that the valve seat has a finely ground finish and is free from sharp edges and burrs.
Resistance to Chemicals
Selection is more complicated than for metal balls as the chemical resistance of plastics materials is inherently more complicated than that of metals.
The two most chemically resistant materials from our range are PTFE and a fluoroelastomer (a Viton® type material). Fluoroelastomers are one of the most heat and fluid resistant synthetic rubbers developed, whilst PTFE is attacked by so few chemicals that it is more practical to describe the exceptions. It is however, important to distinguish between strictly chemical reactions and physical reactions such as absorption which may be inter-related and which may affect a particular application.
The suitability of plastic balls for specific applications is best judged from tests where the balls are subjected to the mechanical stresses, thermal effects and chemical attack likely to occur under working conditions.
Technical advice is freely available, but since we have no control over actual operating conditions we do not guarantee the success of our plastic balls for any particular application and the final choice of material is at the customer’s discretion.
Answers to the following questions will assist us:
1.Intended application 2.Choice of material 3.Operational details – continuous or intermittent 4.Loading 5.Speed 6.Temperature range 7.Medium surrounding the ball 8.Diameter 9.Monthly and annual requirements