I am cutting a 3D surface, about 20" x 20", max Z of 0.7" in soft pine with 3/8" ball nose bit at 6000RPM 100 IPM feed. Every time it shifts Y axis it is at full depth and cause the wood/bit to chatter - this then triggers a limit switch. I have been using the machine for a couple of years now, and this problem has not really been an issue, I just slow the feed down a bit and everything is OK. However with a 3D surface - its going to take 4 hours at 100IPM, I would not like to slow it down any more (besides 70IPM does not fix the problem).
I have tried securing the board more, with no luck.
Any suggestions?