Marks at end of arc

[romaxxcnc]

There was a post here about marks in a circle where the cutter stops and relaxes tool deflection.

All rotary cutting/ milling type machines with cutter side loads will leave a mark against a cutting surface where the cutter dwells.

Cad Cam programs typically offer an Approach/Depart feature to remedy this. Where the cutter moves away from the wall in a small arc before stopping.

-Ron

[gipper]

Ron,

I appreciate the response and understand your explanation. Would tool deflection also cause this on a square pocket where the bit stops in the middle of a side? I do typically run bits with 2" cutting length as I deal with thick stock cutting my guitars.

P.S. Have been running my WD-1 for 3 years now and the machine has performed well for me.

Brian

[romaxxcnc]

Brian,

Yes, anywhere the tool is cutting and then stops or dwells and still rotating against a wall, it will make an indentation. (Incidentally, this is one of the worst things to do to a cutter working with metal, and probably woods too. It wipes the cutting edge right off - friction/heat and no material removal to keep it cool. Like dragging a file and not allowing it to cut, it will dull it quickly).

All machines do it and depending on the cutter load - heavier cuts will be more pronounced. Typically, a finish pass of perhaps .010" is taken to clean the profile. In light cutting this effect is minimized.

For approach and depart functions, the toolpath looks like a teardrop shape inside of a circle. Although they can be used on any profile. BobCadCam has this. Give it a starting point, the radius, and it will build the path for it. The cutter will start at the center of the circle, move out near the edge, swing a small arc and then merge with circle path, at the end, it does the opposite.

-Ron

[gipper]

Ron,
Again thanks for the response. Unfortunately my version of Cut2D does not offer lead in and out options. May be time to upgrade.

Brian