Where I work Cams for internal use machines used to be made from Mehanite and hard ground on a tracer machine with a master.
Over the years material was changed to A6 and hard machined at 52-54 Rc.
We are now chasing down a problem that we are not sure is related or not to the manufacturing method. It is difficult to get the whole story on when this became a problem, but cams that used to last years are lasting months. This is happening to hundreds of cams in a couple of different factories. Some issues are from set-up on the machine, but other are not.
What is weird is the wear pattern seen on the cams, they are getting grooving along the whole profile that is like the rumble strip on the side of the highway.
As you can imagine there are plenty of theories and variables to the problem. I'm interested in other peoples experiences with trying to hard mill cams and if anybody experienced similar wear or failure problems.
These Cams are about 6" in diameter, turn in the 175-225 rpm range, and have a 1.25" unlubricated roller cam follower on it.
We cut the CAMS on a MAZAK FJV-250
Rough Cutting is done with a Z Carbide ½” end mill
Finish Cutting is done with a EXO Carbide 6 Flute end mill
Rough and Finish Pass is done at 2500 RPM moving at 10 IPM (Inches Per Minute). Does not give a "ground finish"
Pictures in next post.
Over the years material was changed to A6 and hard machined at 52-54 Rc.
We are now chasing down a problem that we are not sure is related or not to the manufacturing method. It is difficult to get the whole story on when this became a problem, but cams that used to last years are lasting months. This is happening to hundreds of cams in a couple of different factories. Some issues are from set-up on the machine, but other are not.
What is weird is the wear pattern seen on the cams, they are getting grooving along the whole profile that is like the rumble strip on the side of the highway.
As you can imagine there are plenty of theories and variables to the problem. I'm interested in other peoples experiences with trying to hard mill cams and if anybody experienced similar wear or failure problems.
These Cams are about 6" in diameter, turn in the 175-225 rpm range, and have a 1.25" unlubricated roller cam follower on it.
We cut the CAMS on a MAZAK FJV-250
Rough Cutting is done with a Z Carbide ½” end mill
Finish Cutting is done with a EXO Carbide 6 Flute end mill
Rough and Finish Pass is done at 2500 RPM moving at 10 IPM (Inches Per Minute). Does not give a "ground finish"
Pictures in next post.