Chattering problem during cut
Posted: Sat Jul 28, 2018 11:27 am
I have an HD-4 with a VFD spindle motor (1.5HP) and I have used it quite a bit with pretty good results. However, I am getting a 'chattering' during cuts sometimes, doesn't always do it. Cutting an elliptical recess in a piece of maple and using an offset conventional cut pattern with a 1/4-in em and a depth of cut of 0.11". Work is 3/4-in thick and the pocket is 0.694-in total depth, set up to make 6-passes, feed is 70-in/min . Most of the pass cut goes pretty well, but in the "NE quadrant" of the cut the bit chatters for about the whole quadrant. The rest of that cut is usually pretty smooth. Does it on every pass and the result is that that part of the recess has a definite roughness to it -- the rest of the pocket is pretty smooth. I have gone through and tightened all the bolts on the gantry and the router carriage, but there still seems to be a bit of 'play' in the carriage. If I grab the dust port vacuum hole , I can move the router bit several thousands just by putting pressure up or down. I don't know if this is where to chattering is coming from or not -- I can't tell where anything in the assembly seems to be moving. I have tried varying the rpm, the feed rate and the depth of cut, doesn't seem to matter -- I still get the chatter on the NE quadrant of the cut. Not just a circular patter either, it will do it on a square cut in the same area. (Referencing the center of the pattern as the datum, the chatter is in the +X and +Y quadrant. During the cut, the bit is moving increasing positive X and negative Y, tracing the upper right part of the ellipse.)
Any ideas????
Any ideas????