New ball bearing materials for better wear resistance

Paul Boughton

Lubricant and maintenance-free, xiros polymer ball bearings can endure temperatures of up to 150°C, are highly corrosion-resistant, can be washed and cleaned, are non-magnetic and are light weight.

According to Matthew Aldridge, of igus UK, xiros ball bearings provide an economic alternative for many applications where the use of conventional metallic ball bearings is problematic. These applications are varied, ranging from all kinds of medical equipment, pumps and measurement machines, through to transport and conveying technology – particularly in the industrial sectors of chemicals, food, laboratories and packaging.
 
“These are applications where the focus is not on maximum load and speed, but on other features such as chemical resistance or submerged components,” explains Aldridge. “In such applications, lubricants can be washed out of the metallic, sealed and permanently lubricated ball bearings, so that corrosion becomes a significant problem.”
 
In addition to the lack of lubricant and corrosion, weight reduction, the avoidance of magnetism, very good friction coefficients and longer service life are further benefits of the use of xiros plastic ball bearings.
 
The general purpose ball bearing material xirodur B180, low-price chemical resistant xirodur C160 and high-temperature xirodur A500 are now complemented with the addition of xirodur F180 and xirodur D180 materials.
 
xirodur F180 is a conductive polymer that provides electrostatic discharge (ESD) protection. Bearings from this material can be used permanently at temperatures of up to 80°C and are therefore well-suited to a variety of applications, including those found in the semiconductor, paper processing, textile and glass industries.
 
The second new material is xirodur D180, which is four times more wear-resistant than the general purpose material xirodur B180. The inner and outer ring of the xiros D180 bearing is made of the new high-performance material, the cage is made of PA, the balls either of glass or stainless steel and operating temperature is 80°C.
 
“Our laboratory testing of the xiros D180 bearings indicates that they can be 72 times more wear-resistant than ball bearings made of PEEK,” says Aldridge. “We also tested ball bearings made of PE, PP, PA and POM – all of these gave a significantly shorter service life. Ongoing material optimisation, along with a comprehensive series of tests, has enabled us to increase the service lives of our xiros plastic ball bearings by a factor of 42 since the birth of xiros in 2007.”
 
The range of dimensions has also been increased; igus now offers more than a hundred sizes, shapes and styles. These range from radial and axial bearings, multi-purpose bearings for both linear and rotational movements, ball transfer units, pedestal bearings and flange bearings through to ball bearings with dust shields. “The standard range is supplemented by tailor-made, customer-specific solutions, which are becoming increasingly important,” adds Aldridge.
 
Fig. 1. xirodur D180 - extremely wear-resistant for high rotational speeds.
 
Fig. 2. xirodur B180 - radial deep-grooved ball bearings for absorbing axial forces, lubricant-free ball transfer unit for conveying sensitive materials.