Posted by Stepan Lunin on August 28, 2009 at 10:41:34:
In Reply to: Surface damage on hard cut gears posted by Ivan Doretzkiy on August 27, 2009 at 13:59:50:
Ivan, this is also why hard turning is not recommended for critical applications. Because hard turning is more common you can find publications about crack propagation, overheat and residual stress from hard turning. The alternative solution to the Klingelnberg hard cutting is to do more gentle finish like grinding or lapping. You canít grind 30-100-inch diameter gears, but more gentle hard cutting tool will work just as good as grinding, and without surface burning. During 2007-2008 I was consulting DMG and Overton Gear, strategic partner of Klingelnberg, on developing of an alternative technology for cutting of case hardened marine gears with use of a smaller cutter on 5-axis CNC DMG machines. In 2008 Overton was purchasing 2 DMG machines for cutting of cyclo-palloid (Klingelnberg tooth) gears. Today, a better tooth finishing process should be available from Overton in the US or even from Klingelnberg in Gearmany, since Overton does some tooth cutting for Klingelnberg. The other alternative would be nitriding. Because of the high risk of damage from the hard cut, nitriding may be lower risk option. Or, consider a better process for the case hardened tooth finishing that we offer at Spiral Bevel Corporation.
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