Plastics for low-friction applications – sliding properties explained

Industrial manufacturing requires materials with particularly low friction in many areas. Sliding plastics are the first choice when it comes to low-wear, long-lasting and low-maintenance solutions. In this article you will learn what gives plastics their sliding properties, which materials are particularly suitable and what you should look out for when choosing a material.

What does sliding ability mean in plastics?

Sliding ability describes a material's capacity to generate as little resistance as possible when in contact with another surface. The so-called coefficient of friction plays a decisive role here: the lower this value, the better a material slides. Sliding plastics are characterised by particularly low friction properties and thus help to minimise energy losses, reduce wear and extend the service life of mechanical systems.

Typical applications are plain bearings and bushes, guide rails and strips, gears and rollers as well as machine elements in the food, packaging or automotive industry.

Properties of sliding plastics

In addition to low friction, sliding plastics often have to meet further requirements. These include high wear resistance, low water absorption, chemical resistance, temperature and UV stability as well as good mechanical strength. Some plastics are also modified with additives such as PTFE, graphite or silicone to further improve their sliding properties.

Overview of important sliding plastics

The following table provides a summary of common sliding plastics and their special features:

Plastic	Properties	Typical applications
PTFE	Extremely low coefficient of friction, chemical-resistant, temperature-resistant	Seals, plain bearings, membranes
POM (polyoxymethylene)	High strength, good dimensional stability, very good sliding properties	Gears, slide guides, bearing bushes
PA (polyamide)	High wear resistance, self-lubricating, high impact strength	Rollers, bearings, rope guides
PE-UHMW (ultra-high-molecular-weight polyethylene)	Extremely high abrasion resistance, very low coefficient of friction	Chutes, guide rails, linings
PPS (polyphenylene sulfide)	Very high temperature and chemical resistance, good sliding properties	Pump parts, valve components

Advantages of using sliding plastics

The use of sliding plastics offers numerous advantages, particularly in dynamic applications where metal on metal would otherwise lead to rapid wear or failures. The most important advantages at a glance:

• Low-maintenance: Sliding plastics often enable operation without additional lubrication.
• Energy-efficient: Energy losses are minimised thanks to the low friction.
• Corrosion-free: Plastics do not rust and are insensitive to many media.
• Noise-reducing: Plastic components often run more quietly than metal parts.

Selection criteria for sliding plastics

When choosing the suitable material, criteria such as load and pressure stress, sliding speed and operating temperature as well as contact materials should be taken into account. Environmental influences such as moisture, chemicals or UV radiation and necessary approvals or standards also play an important role.

Modifications to improve sliding ability

Some applications place particularly high demands on sliding ability. Modified plastics are used here. Frequently used additives are:

• PTFE (polytetrafluoroethylene): Improves sliding ability and chemical resistance.
• Graphite: Increases sliding ability while offering good wear resistance at the same time.
• Silicone: Reduces friction but increases flexibility.
• Aramid fibres: Reinforce mechanical properties while offering good sliding ability at the same time.

These modifications make it possible to adapt plastic components even more precisely to the respective application.

Conclusion

Sliding plastics offer enormous advantages in low-friction applications and are indispensable for many modern industrial sectors. The right choice of material makes a decisive contribution to optimising the performance, service life and efficiency of machines and components. A careful review of the operating conditions and requirements is the key to a permanently successful solution.