Chatter in 1/4 MDF

[richard862]

We are using a PRS Alpha 60x96 (2 spindles) to profile cut shapes (up to 40 per panel) out of 30/48 MDF panels using a CMT 3/16 DOWNCUT SPIRAL BIT at 3.0 IPS and 14000 RPM. We are getting various degrees of chatter at what appears to be random locations on the parts. Sometimes the chatter is on longe smooth curves and at other times it is in small .250 slots. We have tried adjusting the ramping which helped some. We've been running the same programs for about two years and it seems the problem is getting worse. I've attached a picture of the chatter and the profile settings used.

[knight_toolworks]

may be some bit flex. though with mdf you don't usually have much. If you have a 1/4" bit to test it.

[bleeth]

Sounds mechanical. Good chance it's time for a pinion gear change. At the very least check all your bolts for tightness and verify your motors are snug against the rack. Make sure you are not getting it from the spur gears not being tight on the shafts.