Calibrating for 3D printing

I would like some advice for calibrating for my 3D print extruder that I have for my MPCNC. I have calibrated my Printrbot Simple by tweaking the M92 values and I would assume I should do the same with the my MPCNC. I am reaching out to everyone since I do not want to inadvertently affect the milling or lasing.

Please share your thoughts.

These values should all be spot on unless you have changed something. The only problem any printers used to have were hobbed bolts and they needed calibration. We use gears on every axis our values should not change. How far off are your prints?

When you say “calibrating,” do you mean your prints don’t match the dimensions of the models? If you’re talking instead about surface features, it may be an issue with the extruder driver voltage. Ryan helped me dial in mine and it’s working fantastically now.

When I say calibrate I am really talking about dialing in the size. I printed a test block that is 40x40 and the X is 39.23, the Y is 40.12 and Z is 39.71 The 20x20 is X 19.28, Y 19.98 and Z 19.89
Test Block
I know I am splitting hairs but on my PSM I adjusted my M92 to get it spot on and I can do this on the MPCNC and I think it will likely make the lasing and milling more accurate but I wanted to reach out to everyone to see what they thought.

I completely understand. You want this to be as accurate as possible. We can assume the Marlin firmware is dialed in, as it seems to be working on many MPCNCs. In my case, one of my machines prints the 20mm hollow calibration cube ( at about 19.6 x 19.8 x 20.1. That’s pretty darn close, but I assume it’s due to backlash that I still have to work out of my system.

Just for information, you might want to check out an interesting guide on calibration at’s_Calibration_Guide.