steve10778
Aluminum
- Joined
- Nov 22, 2010
- Location
- ohio
Needs some ideas here,,,,
96 vf2 having chatter problems when milling id circle. The chatter always occurs at 95 degrees to 120 and 275 degrees to 300 degrees. Milling 1.0 inch deep, .002,.005,.010 stepover ranges, no change chatter every time in the same two spots.
here is what i have done so far:
New spindle
tried different table locations
various materials, steel aluminum
5 flute carbide, 2 flute, 4 flute
speed and feed up and down, no effect
adjusted leveling foot on one side to twist bed, to see if it had any effect(squareness) no effect so put back
checked y axis bearing locknut to see if had worked loose, no.
climb milling or conventional, chatter appears in the same area. ( i would have thought it would have reversed to the other side of the quadrants, but it did not)
ball bar test shows good results
backlash according to ball bar is .00015 or less(with comps on) measured backlash(deflection with full return to indicator zero) is about .0005 to .0008
circularity is very good ( a few tenths), no quadrant marks, except chatter after the 90 and 270 quadrants.
so i started to suspect servo issues, not servo mismatch but maybe oscillation while interpolating, adjusted d gain to stiffen axis up, no change, reverted settings to normal
adjusted p gain, no help, reverted that back too.
did not try any integral, feedforward, or accel parameter tweaks.
Im thinking of just replacing the thrust bearings on both x and y, but im just not so sure.
so what does everyone else think?
thanks,
steve
96 vf2 having chatter problems when milling id circle. The chatter always occurs at 95 degrees to 120 and 275 degrees to 300 degrees. Milling 1.0 inch deep, .002,.005,.010 stepover ranges, no change chatter every time in the same two spots.
here is what i have done so far:
New spindle
tried different table locations
various materials, steel aluminum
5 flute carbide, 2 flute, 4 flute
speed and feed up and down, no effect
adjusted leveling foot on one side to twist bed, to see if it had any effect(squareness) no effect so put back
checked y axis bearing locknut to see if had worked loose, no.
climb milling or conventional, chatter appears in the same area. ( i would have thought it would have reversed to the other side of the quadrants, but it did not)
ball bar test shows good results
backlash according to ball bar is .00015 or less(with comps on) measured backlash(deflection with full return to indicator zero) is about .0005 to .0008
circularity is very good ( a few tenths), no quadrant marks, except chatter after the 90 and 270 quadrants.
so i started to suspect servo issues, not servo mismatch but maybe oscillation while interpolating, adjusted d gain to stiffen axis up, no change, reverted settings to normal
adjusted p gain, no help, reverted that back too.
did not try any integral, feedforward, or accel parameter tweaks.
Im thinking of just replacing the thrust bearings on both x and y, but im just not so sure.
so what does everyone else think?
thanks,
steve