I have a New Carve CNC (lead screws, no belts) and an Openbuilds BlackBox controller, which I have owned now for roughly 7 months. The machine is mostly used for cutting 6061 aluminum and it has worked perfectly until now. A few weeks ago my Openbuilds Blackbox controller started throwing EEPROM errors. I contacted Openbuilds and they sent me a new Blackbox controller. I connected the new controller, restored my old GRBL settings, and proceeded to cut an aluminum intake plenum top. It wasn't until after the job was done that I noticed that the plenum top was 0.25" short in the X-axis and 0.010" short in the Y-axis - I have done dozens of these tops prior without any issue. Today I spent the time dialing in the machine with a dial indicator (the machine was off by 0.007" in some instances), made adjustments to GRBL settings $100, $101, and $102, and then proceeded to run a test job in MDF. No dice. The issue still persisted and was still off by 0.25" in the X-Axis and 0.010" in Y-Axis. It's accurately inaccurate! I'm stumped. I haven't made any changes to the machine other than swapping out the Blackbox controller and the .gcode file that I used is the same that I was using prior to swapping out the controller. Literally, everything is the same except the controller. I tried to hook up the old controller to see if I could pull up the original GRBL settings I was using to check for any inconsistency between the two, but the firmware isn't recognized on the controller - basically, it's toast. Also, I've tried to enable $13 (report inches) in the GRBL settings, but I'm unable to enable it. It defaults back to "disabled" once I hit save. Just to clarify: When I say that the machine was "off by 0.007"', I mean when I jogged the machine 0.500" in the X-axis via Openbuilds Control, the dial indicator would show the actual movement distance was 0.507"; when I jogged in the Y-axis 0.500" the dial indicator showed 0.498". I am using Fusion360. Any help would be greatly appreciated!
Keep that on mm. Control works in mm in the backend, and converts to inches for display purposes for you. If you do change it to Inch, you'd be off by *25.4 on all displayed units The BlackBox itself cannot contribute to dimensional issues. Its either mechanical, or calibration related. Its been in use for a while, check stop collars, screws on shaft couplers, etc are all still tight, symptoms look a lot more like backlash. Once its all tight again, recalibate
And calibrate over the longest distance you can measure. A dial indicator is too short, you need a 500mm steel rule. The dial indicator will show you the cyclical error in the lead screw but not the cumulative error over the length of travel and it is the cumulative error we are calibrating for.
