Hi, I'm new to CNC, and im trying to cut multiple parts from thick 18mm baltic birch plywood, that are cut to half sheets (1250mm x 1250mm). I'm struggling to fix it correctly to my waste board. For the moment I use screws, at positions depending on my design (I've multiple half sheet designs). But its difficult, because I must carefully measure to place my screw, not to cut over them (especially since I use a big roundover bit). The second problem is that it seems I cant fix it exactly flat to my waste board, because my cuts always varies in depth (it's always deeper on the periphery, so the center of my board must be slightly surelevated, because my waste board has been surfaced). That's especially visible with the roundover bit. The things is that there is not much clearance around the board to use sophisticated clamping system. What are my other choices? Thanks!
You could maybe design in the screw holes in your CAD file. Then lay the sheet on the machine and run a toolpath just for these pilot holes first. After they are done, screw it down and cut the rest. The weight of the sheet should be enough to hold it in place for just simple drilling toolpaths. The nice thing is that if you repeatedly make the same things, and you had some sort of indexing system where the sheet was always in the same place, you could repeatedly use the same screw holes in your waste board which would extend its life.