I did something that is probably unusual but it brought a strange problem to light.
I did an inside offset and an outside offset to a shape at the same depth and it left an area untouched between the two that was about 25/1000 wide. I had 0 finish allowance on both. Is this normal? The end mill I was using was 1/2" and it measures pretty exact.
Well, this came into play again toady. I was doing an inside contour that had some pretty tight tolerances for a bearing. It needed a .197" diameter. Corel had the correct measurement, but I couldn't figure out how to read a DXF file to confirm that it had the correct value - but it seems to have this problem regardless of whether it's a shape made up of individual points or true arcs (and only on contours). It ended up making an inside contour of .184". I made this with a .005 finishing pass first, then a 0 finishing pass at 10 IPM so it shouldn't have been due to end mill deflection. It was a 1/8" end mill. From what I see It appears to be doing a minimum of .0125 offset even when it's set to 0.
Any thoughts?