Hello all, first off to start I have a workbee 1010 that I have upgraded with a CNC4newbies Z axis. tI am having an issue that has happened since day one of owning the machine. No matter how many times I calibrate the Z-axis steps it seems like it’s always cutting way way deeper then it should. I am using the open builds z-probe, triple checked tramming and just leveled my spoil board again last night. Currently I am trying to engrave my logo on some aluminum plate and am only calling for .001 on the first pass and .0015 on the second pass and I am prob getting .025 the first pass. I though it might be G-code related, I am using Carbide Create for my cad and cam and it all looks normal with the exception of one line I have to delete before every job. (Line 9, M6-TXXX, it throws as error if I try to run the g-code with this line, I have just been deleting it) other then the depth issue everything else looks great and is sized correctly. I’m really new to most CNC stuff so I am slowly learning, but this is really irritating as it’s happened since for months and can’t figure out why it’s wanting to take more depth then it should.
So I ran a test with the G-code, for every line that showed G1 Z-0.025 I replaced it with G1 Z-0.001 and every line that shows G1 Z-0.038 I changed to G1 Z-0.002 and it does exactly what I want it to. I know that the G-code is in MM, and the .025MM and 0.38MM in the G-code match up with my .001'' measurement that I was asking it do but it was still engraving way deeper then that. the machine seems capable of doing what I am asking after I change the code as the test piece turned out good. just cant seem to see why its doing what its doing with the correct measurements in the G-code. here is a copy of the g-code I am trying to run for anyone that might want to look at it
I'd say your Z is not calibrated correctly, it is x25 off. (my first check was that your file has the required G21 code in it to set MM mode because obviously if it did not and GRBL was in G20 (inch) mode then moving Z by 0.025 would move 25 thou rather than 1 thou.) Internally GRBL is all millimeters, including all the calibration numbers, so you need to re-do the calibration very carefully with a good mm ruler. I would do this: put in a short tool, maybe a blunt stub of a broken bit. carefully set Z zero to the surface (I use the paper method, my paper is 0.1mm thick). give command G21 G1 Z20 F100 that should raise it exactly 20mm, you can change this number to match the width of your steel ruler, and then the ruler should just pass under the tool, not even a bit of paper should fit. If it DOES NOT raise by your given number of millimeters, then I would return to zero and raise by as much as I safely can. Calibration works best over long distances, do not jog, it must be a single command. Search the resources section for the calibration how-to if you don't know how to do it. Remember to return to 0 before changing any numbers in GRBL and cross check carefully after the change. Use as many decimal digits as you have available, roundoff errors will BITE you. As a side note I proved to myself that it is possible to calibrate a completely unknown system by starting with a stepspermm of '1' and doing 3 to 5 calibrations, getting ever closer at each step.
