Corner Tear Out

[3ps]

Hi, I need some suggestions to stop the chipping of sharp corners on profile cuts. Example: cutting out a square shape, The nature of the bit rotation and the direction moving around a corner ends up chipping out two corners that no longer have support to prevent this. I am cutting poplar @ around .8 ips. Any help would be appreciated. Thanks Doug

[woodworx]

slow corner speed. use down spiral bit.

[Gary Campbell]

Doug..
Toolpath so that the cross grain is cut first, then with the grain. This would be similar to running a panel thru a raised panel bit. If the cross grain edges are cut last, they will chip out.
Gary

[3ps]

Thanks for the tips, Where do I adjust the corner speed? Also how do you go about setting up the toolpath to cut the cross grain ends first? I tried looking in the toolpath screen and could not find anything that would depict what is cut first. In node editing you can pick the start point and select climb or conventional in the toolpath screen.Thanks Doug

[srwtlc]

Doug,

Slow corner speed is adjusted in SB3 under VR (Value Ramps). This may be of little help though as the problem is more related to the toolpath.

While node editing, as you stated, you can change the start point. When you create the toolpath, put a check in "Use Vector Start Points".

Another thing that sometimes helps, is to put a very slight radius on the corners if it's acceptable. While creating the toolpath you can also choose to have or not have "Sharp external corners" on the "Corners" Tab.

Poplar is nasty for that too!

[rhfurniture]

Sometimes I resort to drilling a hole at the corner of the cut first, so as to cut the fibres that could tear out before their support gets taken away. Can work a treat.

R.

[3ps]

Ralph, This sounds like the way to go, Heading downstairs to try it. I will report back with the results. Doug