I've been running a part on a VF2. 12K spindle. HSM activated
I've had to move it to a MiniMill SS. 10K spindle HSM activated
Part is 6061 T6 Aluminium.
The was had an excellent finish coming off of the VF2
Now on the Mini Mill running at 80% feed(to compensate for the lack of 2000 rpm) the finish is unacceptable.
It isn't chatter. It happens in XY as well as Z. For lack of a better way to describe it. The machine seems to be shuddering for a short distance after a direction change. Like it has to step left and right to find the correct direction.
In the first photo you can see the shudder mark as the toolpath comes off of the straight edge onto the sweeping radius. If you look at the sweeping radius above the step it is perfect. It was like that all the way around until the path below the step was cut and the cutters flutes put the marks all the way up. The waves are ±2.5mm crest to crest.
The next photos you can see the up down movement in Z. Feed rates range from 5000mm/min - 2500mm/min. These were just fine on the VF2.
I have an idea that the machine has backlash and the previous owner tried to eliminate it electronically and not physically.
Another possibility is parameter or setting variations. Can someone point me in the direction on which ones to look for.
3rd possibility is the machine is not 100% level. I saw the setting up, and I'm a fussy barstard. The technician kept telling me "that's within tolerance". Not my tolerance!
Or it is rocking on the feet. It does not feel like it is moving as far as I can tell.
Slowing the feeds down does reduce the shudder but does not eliminate the problem.
Any ideas?