Posted by Chuck Awot on August 27, 2000 at 23:57:20:
In Reply to: Hobbing posted by Kevin on August 01, 2000 at 08:02:08:
In certain applications, carbide can be used in any older machine that is in reasonably good condition. I know a lot of people that cut tons of non-ferrous gears (aluminum, bronze, bakelite, etc.) in older machines using carbide. These are typically finer pitches, that are well within the rated pitch limits of the machines. When cutting steel gears with carbide, machine rigidity is extremely important. Carbide is very unforgiving, and any looseness or especially backlash in the hob head will "shell" the hob almost immediately. Any excessive runout in the hob will only make matters worse. With skiving or hard hobbing, you are often working with material hardnesses that are up around Rc 60-62, and machine rigidity becomes even more of an issue. All of your tooling and fixturing often has to be designed specifically around the process, to provide maximum rigidity. Cutting oils also become important with skiving and hard hobbing, and even the cutting pattern has relevence. (Conventional vs. Climb cutting). I have done a lot of carbide cutting on both gears and worms, and have done a lot on both hard hobbing and skiving as well. If you would like a little more information on it, contact me at firstname.lastname@example.org.
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