Wednesday, January 01, 2025
Repeated Calibration Zigzag
Happy New Year! Is there anything that I should put at the top of my New Year's Resolution list to release, document, or improve things that you want to see? 43 people have checked the new git repo, please do tell.
I wrote the GCODE for a calibration zigzag, 500μm lengths, 50μm spacing, repeated along X & Y with a staircase gradually lifting the probe by 2μm for each segment. I ran it twice, and took an image of the calibration slide with the same camera settings:
Immediate things, X scale is off, the lines are only 415μm long, not 500, fixed that in GRBL config.
Lighter lines are generally more consistent, which figures as less stress on the probe.
Y axis seems to have consistency issues being +/-30μm. Needs an overhaul. I'll probably do a diagonal calibration slide later to test the overhaul. Even so, that's literally within a hair's breadth.
[Edit: It seems one of the bands used for backlash has broken, which is going to tilt the drive nut...]
But the X axis, other than the scaling issue, seems to be positioning +/- 10μm absolute which I am moderately happy with for now.
Start point divots are reduced, possibly by a 5x reduction in plunge speed. I noticed a lot of vibration of the probe through the microscope. Not sure how much of that is the axis mount, and how much flexibility in the probe, but both need to be addressed.
I'll take a peek to see what's up with the Y axis. Now I have had experience in handling the setup, I think I might risk a decent probe with a more symmetrical cross section and see if that improves things.
This all brings to the fore the question of end stops, so that I can guarantee the same starting point every time and thus experimental consistency.
