Dental bearing ups device life by four

New bearing production and sealing techniques are helping manufacturers of dental hand pieces up warranties from six months to two years. Dean Palmer reports New bearing production techniques, developed by bearings specialist Barden as part of a four-year product improvement and reliability programme, are enabling manufacturers of dental hand pieces achieve up to four fold increases in the length of warranty periods which they can offer. While most dental device manufacturers offer a six- or 12-month warranty, in some cases Barden's programme is extending this period to two years. Repeated sterilisation, operating debris and lubrication of dental hand pieces make for a very arduous working environment so bearing turbine performance is critical. Barden's improvement programme therefore focuses on bearing production and sealing techniques. On the production side, new techniques for finishing the inner and outer ring raceways of dental turbine bearings were developed. The raceways, 0.15mm deep, accommodate 1mm diameter balls and benefit from a new honing process, which improves the quality, surface finish and relative roundness. On the sealing side, an improved seal design reduces the critical gap between the integral shield and the bearing inner ring to just 0.05mm, a 60% reduction compared to conventional shield and circlips designs. This means the problem of shield ejection is overcome, contamination is therefore less and lubricant retention is much greater. And, operating noise from the compressed air passing through the bearing is reduced. Barden also reviewed its dental bearing assembly process with a full 5S audit, to ensure cleanliness of product. Laminar flow clean air benches are used to control the number and size of airborne particles in the range 5microns to 0.5microns