Isotropic Super Finishing of large gears
In view of the ever growing durability demands on gears used in large gearboxes, Osro and REM have jointly developed machines and Isotropic Super Finishing (ISF) processes, specifically tailored to improve the surface finish of large gears.
The machines used in the ISF Process are designed to cope with the extreme weight of these large components. OSF has a range of machines suitable for Isotropic Super Finishing gears weighing up to 2000 kgs. Pinions up to 1000 kgs and Inverse gears, (sometimes referred as the hollow wheels), up to 2000 kgs.
The Isotropic Super Finishing process uses the effective and proven REM ISF method of surface refinement to increase the wear resistance of the gears. The surface improvement of the gear flanks results in a reduction in grey staining and micro pitting. The improved surface finish generated by the ISF process produces an improved load carrying capacity, lubrication regime,(EHL), and consequently greatly reduced wear.
The benefits are:
Reduction of surface roughness
Improved load carrying capacity
Improvement of grey staining resistance
Elimination of running in wear
Improvement of scuffing load capacity
Improvement of micro-pitting resistance
Reduction in lubricant filtration maintenance
Lower operating costs
Lower operating temperatures
The advantages of the Process can be applied to all gears whatever the application. However, specifically planetary gearboxes having Low Speed - High Load operating regimes gain tremendous benefit from the Isotropic Super Finishing process, particularly when not only the Planets and the Sun wheel, but also the Inverse gear is superfinished.
The process is also suitable for gearboxes which suffer from extreme wear and have to be rebuilt. Experience has shown that Isotropic Super Finishing of the replacement new gears, prior to assembly, can produce an up to three-fold increase in life expectancy.
Profilometer readings
Both OSF and Osro GmbH have worked closely with several universities to investigate the effect of Isotropic Super Finishing on gears. In particular the companies have been involved in two FVA projects, ( projects 286 III & 521) as well an investigation carried out by the RWTH Aachen to compare the effect of Isotropic Super Finishing and coatings. A diagram showing the results of these tests is shown below.