Continuing the discussion from Help: What do I need to do to eliminate gaps around inlay using advanced v carve:
Have had lots of difficulty achieving precision v-carve inlays that don’t produce gaps at the surface. Since December, have had multiple issues that one by one I’ve eliminated—spindle wobble, loose screws in Z, loose screws in gantry mount, router bits [maybe?] out of conformity. Believe all that is resolved, machine calibration checks out, and have produced some tests with success that makes me think I’m on track, then all of sudden failure again. Only this morning have I stumbled onto what may be at the root, but I still don’t know if it’s pilot error in Carbide Create on my part, or my lack of understanding on how to correctly manipulate CC, or something buggy in the code that is giving me inaccurate tool paths occasionally. I have studied the tutorial on how to vcarve inlay in version 4, but I believe I’m right in understanding the new functionality in advanced vcarve with start and max depth should achieve the same result as cheating the z-zero in the tutorial. Others with better insight than me might have a better notion of that.
So, on to what I stumbled on. Including files for the small test of an intricate lettering for my farm’s logo that I’m trying to inlay on an end grain cutting board. Making several test cuts before I [plunge] into the end grain walnut and ruin a rather expensive bit of wood. The test pocket comes out as expected; I have 0 and .25 max depth. To test that advanced vcarve places the tool path accurately, I created an offset tool path inside = tan of 18 degrees x .25 max depth = .0395. In simulation, I can visually see the tool path and the offset vector are essentially on top of each other. Seems right.
For the inlay, I do have a pocketing pass to clear away material before advanced vcarve as the settings I’m striving for are .22 start and .28 max, which I expect leaves .03 glue gap in the pocket inlay and .06 saw gap above pocket surface. So if I understand advanced vcarve start depth, the idea is to achieve the exact width of the inlay vector at start depth, so when inserted into the inlay everything above that plane sits into the pocket and everything below that plane protrudes above the surface of the pocket. So for 18 degrees and .22 depth, I believe the tool path should be offset .0348. What I find is that the tool path is actually very close to the inlay vector. Through trial an error, made offset tool paths to compare to the tool path in simulation and for .22/.28 it is very close to being offset by .01. Back to trig and believe that implies a depth of .06, which incidentally is the difference between start and max. So I changed settings, did the same checking, and feels like I can confirm the tool path is being calculated offset from the inlay vector by the difference of start and max.
So back to my original question, am I not designing correctly in CC, is CC bugging, or is this just not functionally available in CC [other than the version 4 tutorial on manipulating z-zero / or designing offset tool paths manually using property geometry]?
Has been a tremendous learning experience for me getting to know the Shapeoko Pro better as I approach my 1-year anniversary with the machine and would really like to get this inlay carving figured out. Not an engineer or mathematician by training, so no guarantee my calc’s are right either. Appreciate any other insights.