GRW bearing lubrication tests yield maximum wear life for medical and dental instruments

GRW High Precision Bearings, one of the world’s largest producers of precision bearings, revealed results from its extensive bearing lubrication testing, promising longer life of dental and medical equipment through the optimized use of lubricants.
Dental and medical device miniature ball bearings depend on lubrication for optimal performance and reliability. Using extensive laboratory testing of 30 lubricants from different manufacturers, GRW identified five autoclave resistant lubricants most suitable for use in medical applications.
According to Robert-Koch-Institute guidelines, autoclave sterilization is mandatory for dental and medical instruments. Dental and surgical hand pieces must be autoclaved with superheated steam, and no re-lubrication can occur due to contamination risks. These sterilization processes pose a particular challenge to ball bearing lubricants.
GRW’s lab tested 30 lubricants, each to 1,000 sterilization cycles with superheated steam. Initial testing eliminated 11 of the lubricants. The remaining 19 lubricants were subjected to analytical and visual testing criteria including weight, optical changes, scanning electron micrographic inspections and infrared spectra. Five lubricants proved capable of withstanding repeated sterilization. GRW testing proved that the best performing lubricants for medical and dental hand pieces consisted of polyurea-thickened greases using a base of mineral oil or PAO (polyalphaolefin).
GRW also performed high-speed running tests, (such as in dental turbines running at 500,000 rpm,) noise (GPR) and starting torque behavior tests using GRW’s in-house dental test stand. These tests revealed that any increase in starting torque, caused by viscosity changes in the lubricant, resulted in considerable heat generation within each bearing. Infrared spectroscopy and SEM-analysis were used to determine any significant changes or grease sample alterations. Considering all known criteria, GRW’s testing revealed the best overall results were achieved using greases with a base of mineral oil or PAO.
(June 10, 2013)