Flared Corners- What is causing it?

[GalenL]

Hello All,

I have been using my shopbot for a couple of years now but have finally taken the time to run test cuts for feed & speed. I noticed that at the corners, cut line is flaring out perhaps 1/32 which is probably enough to make our old edgebander misapply glue. I am cutting with a 3/8" mortise compression bit in 2 passes, 6 IPM @ 9000 RPM. I put in a .020 offset and even put a lead in through ramp. The flare is most noticeable at the bit start/end corner. Any suggestions?

26261

[Brady Watson]

6 IPM @ 9000 RPM. ... Any suggestions?

Yes. Increase RPM to 13,000. Change move speed to 3,1 [MS,xy speed, z speed] and try again. Makes sure speeds are inches per second. Othewise run 180,60 inches per minute...

-B

[bleeth]

Put the start point at the back of the cabinet part and forget about the little corner flare.
Cutting my move speed in half on a batch of cabinets is out of the question.
I also cut at 6ips. But I also used to get that same flare when my max cutting speed was around 3-3.5 with Gecko box.

[GalenL]

Thanks for the advice. I tried keeping the movement speed at 6 ips and running the spindle at 12,000 rpm. Seems to have reduced the flare a little to the point where it is acceptable, but the bit gets rather hot.

[donclifton]

Am I missing something. @ 360inches per min (6ips ) and @ 12000rpm that's only 33.333 rpm per inch.
Don Clifton