Product category:
Bearings
News Release from: The Barden Corporation | Subject: Dental bearings
Edited by the Engineeringtalk Editorial
Team on 17 September 2004
Aerospace technology moves to dental
bearings
New bearing production techniques are enabling manufacturers of dental handpieces to achieve up to fourfold increases in the length of warranty periods which they can offer.
New bearing production techniques, developed by Barden as part of a 4-year product improvement and reliability programme, are enabling manufacturers of dental handpieces to achieve up to fourfold increases in the length of warranty periods which they can offer Compared with the market demand for extending warranty periods from 6 to 12 months, Barden's programme is enabling manufacturers to consider offering warranties of 18 months, or even 2 years
Until recently, the generally accepted warranty period for dental handpieces was just 6 months.
If this seems short, it must be set against an operating regime that must be one of the most arduous imaginable.
The requirement for repeated sterilisation of the headpiece, combined with effects of operating debris and lubrication, impact particularly on the ultra-high-speed (up to 500,000rev/min) turbine bearings used in the handpieces, often causing them to fail prematurely.
As a major supplier to the dental market, Barden has been at the centre of developments to improve all areas of dental turbine bearing performance.
Barden was one of the first to introduce the increased life and high-speed benefits of hybrid dental bearings to the market, and also first to respond to the market demand to increase warranties on handpieces from 6 to 12 months.
The vehicle employed to achieve the latter objective is an ongoing product improvement and reliability programme.
Central to its success is the combination of new production and sealing techniques with initiatives in assembly and quality control procedures.
In the production area, particular attention has been focused on techniques for finishing the inner and outer ring raceways of dental turbine bearings.
The raceways, just 0.15mm deep and accommodating 1mm diameter balls, are benefiting from a new honing technique developed by Barden, which improves both the quality of their surface finish and their relative roundness.
Safeguarding the improvements delivered by the new honing technique is improved bearing sealing; the second key element in Barden's improvement programme for dental turbine bearings.
The improved sealing design reduces the critical gap between the integral shield and the bearing inner ring to just 0.050mm, a 60% reduction compared to conventional shield and circlip designs.
The benefits of this development are fourfold.
First, the problem of shield ejection is overcome.
Secondly, exclusion of contamination is much improved.
Thirdly, lubricant retention is much greater.
Forthly, operating noise from the compressed air passing through the bearing is much reduced.
Having addressed both the issues of manufacturing and design in its improvement programme, Barden turned its attention to bearing assembly.
Here, a full 5S audit of the company's dental bearing assembly area was undertaken to determine that cleanliness levels for bearings operating at ultrahigh speeds could be met, consistently.
On completion of the audit, the dental bearing assembly area was relocated into a section similar to that used for the assembly of the critical aerospace instrument bearings.
Here, laminar flow clean air benches are employed to control the number and size of airborne particles in the range from 5 to 0.5um.
Finally, and in conjunction with the restructure of the assembly area, two other actions were completed as part of the product improvement project.
Similar quality control procedures to those used for the aerospace product market sector were adopted for all dental bearings and a full employee-training programme was completed.
This included basic bearing design, application familiarisation, and bearing handling procedures.
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