What should I be verifying when my Z appears to be off a bit when I start a project? When I start running the G-code using gSender and trying to bore a hole for example the bit will start the circling motion well above the piece of wood (maybe a 1mm or less) and eventually go far enough down to start cutting wood. This also happened to me today when trying make a bowl and can tell the bit was not touching the wood when it should have been.
I am using the auto zero touch plate for XYZ on top corner of stock and Fusion 360. What should I be double checking to make sure Z is accurate?
I would start by setting up a board and zeroing like usual. Then either move just off the board and goto Z 0 or jog slowly down to see if the touch block is working/setup correctly. Try to use a board with nice corners or don’t compare Z 0 to the very edge of the board. If it looks off at this point I’d check the gSender setting for AutoZero thickness and make sure it’s the same as your block.
EDIT: You might want to double check the bit size/mode in the probe tab. I don’t have an AutoZero but Auto vs Tip might change depending on bit type. Something to check anyway.
If it’s zeroing correctly at that corner then I would move onto checking the spoilboard surface and the stock to see if it’s an even thickness.
If you zero to the top of a small block of wood you can jog to different areas and see if the block fits the same. Something like that is faster than lowering the bit to the spoilboard and prevents crashing. I’d check 9 spots like the center of each square in a tic tac toe board. Either that or just resurface taking off a thin layer. Your spoilboard, your choice.
If it’s off by less than 1mm I’m guessing its uneven stock or spoilboard. I have a LongMill with self made table and it’s not uncommon for the spoilboard to be off 0.5-1mm because of weather changes.
Thanks for the reply.. I’ll check those items tomorrow.. could there be something in Fusion that I am doing wrong? I did test Z zero earlier and appeared it was exactly at the top of the board at the corner.
I’m not clear if the auto-zero plate compensates for not placing the bit at exactly the depth specified in the Fusion CAM settings for that bit and if that would cause an issue?
If I’m understanding that right it should. That’s what the thickness setting is gSender’s settings does. It probes the touch block and sets Z 0 to that set distance below where it made contact. So the bit won’t be at Z 0 after the probe. But if you then move down and Z 0 is kissing the top of the material then that is working perfectly.
I’ve only a little experience using Fusion years ago and I never used the CAM part so I can’t help with anything Fusion specific.
When I want to know if my material needs surfacing, I pick a wee slice of 2x2 waste of the floor ( theres always some laying atound.) And zero Z on top of that, lower Z to zero and start moving about the material, stopping a certain points and try fit my trusty zero check tool. This gvies me enough knowledge on how cupped bend or unequal te surface of my material actual is.
After that I will contemplate for a moment, if Iam good with the result. A simple sign can get away with more cupping than a 3d carve. I might even compensate and zero on the deepest part of the board if the deviations aren’t too bad. I even went so far as to split parts of the design and rezero on its location to mitigate surfacing the material. Sufacing isnt always an option.
It looks like the board is at least 0.5mm difference from one area to the next as you and @_Michael suggested it may be. This happened to be a scrap piece of regular dimension lumber from a big box store so didn’t realize there could be that much difference.
