Using a V bit to sharpen corners of a pocket

[alex_holden]

Hi, newbie question I'm afraid.

I'm trying to relief carve some stamps. I've got as far as using a pocketing MOP with an 1/8" end mill to remove the bulk of the background material. Is there a way to generate another toolpath that uses a 60 degree V bit to sharpen up the internal corners a bit and also eliminate the 'bridges' where the inner shape has inadvertently become connected to the outer circle, without unnecessarily re-cutting all of the background area?

I have attached my work file.

[kvom]

Just use a profile MOP on the polylines needing cleanup.

[Bubba]

As Kvom suggested use profile MOP. Try 1/16 Dia bit maybe it clean up enough.. V-Bit may work as long as the depth very shallow. 

[EddyCurrent]

A 1mm tool around the letters and inside the inner circle does the trick.

[alex_holden]

Thanks, I got there in the end, and your suggestions to use a profiling operation set me off on the right track.

What I needed to do was:
1. Create a profile MOP to cut the inside of the triangular counter.
2. Set the stock surface and target depth the same as in the pocketing MOP.
3. Turn on Corner Overcut = True.
4. Configure the tool bit (60 degree V, 0 diameter).
5. Set the roughing clearance to (pocket depth) / Tan 60.

I don't think I could have figured this out without the help of the CAMotics simulator! I've attached a rendering of the 'sharpened' counter showing the pocket cut to full depth with an end mill, then the corners sharpened with a V bit.

I haven't yet tried doing the outside of the symbol but I imagine the same procedure will work.

[EddyCurrent]

I've just realised that because it's a stamp, there would be no need to profile at the full depth, the method you show is therefore okay and does leave very sharp corners.
I wonder if this thread and script could be used for the purpose ? http://www.cambam.co.uk/forum/index.php?topic=4065.msg27844#msg27844

[alex_holden]

Thanks Eddy. In the end the V bit didn't cut as cleanly as I hoped, but a few minutes with a sharp skew chisel fixed it. Attached is a photo of the finished stamp. 50mm diameter, end grain limewood.