Hi Seth,
I have working code but need to get a consistent procedure and Fusion Contour is not helping. This is specifically about how Fusion sets the Z height.
For some years I have used PCB-Gcode and as such it does not have a stock model. The topmost surface of the board, the copper surface, was set as zero height and you would nominate a cut depth relative to that surface. Standard 1 oz.sq.yd PCB material has a copper layer 35um thick. As standard procedure I would nominate a cut depth of 60um, that is the 35um of copper plus an extra 25um down into the fiberglass core. This ensured reliable isolation where any minor unforseen vertical variation (within 25um) would not cause a failure.
Have attached a couple of pics of the board I'm working on now. See how the Top Etch I was able to set the zero height at the top of the copper and I nominated the depth of cut be the surface of the fiberglass core PLUS 0.01mm or 10um. Note that Fusion Contour has delivered the results nicely. That is to say that the TopHeight is 0mm and the BottomHeight is -0.045mm. This is ideal and replicates how PCB-Gcode works.
The second pic is the bottom side of the same board and I used the same method to generate the toolpath but note that the zero height is set at the core surface so the TopHeight is +0.035mm and the BottomHeight is -0.01mm. Despite using an identical procedure I end up with two different toolpaths.
The TopEtch toolpath ran perfectly, once processed by Autoleveller it maintained near perfect Z height throughout the board. Not so the BotEtch toolpath. In particular when I set the material in the machine the machine get touched off to the prevailing upper most surface namely the top of the copper. Thus when the tool path runs it runs 35um too high. I can and have manually corrected this but its not ideal.
The issue appears to be when I set the origin in the first Setup. I'd like to think that the geometry of the model includes both the 35um layer of copper traces and the fibreglass core, and when I set the top corner of the board as origin it is at the same height as the topmost surface of the copper. In the case of the TopEtch toolpath that worked perfectly but not so in the BotEtch toolpath. I've been over the selection process a dozen times and cannot find a suitable procedure that gives repeatable results.
Can you make any suggestions?. One idea I had was to in the PCB design place a pad at the intended origin of the board and set the WCS on the surface of that pad. I'd really rather not have to bother with that, but I do need absolutely repeatable results, otherwise making PCBs requires expert attention while at the machine to correct for any changes between toolpath references.
Craig