Musings and Experiments on the Art and Science of 3D Printing


Video: Delta Printer Calibration Diagnostics

By SublimeLayers Monday, April 9, 2018
Here's a tutorial showing how I approach diagnosing delta calibration issues using a bed probing macro. You might learn a little bit about how RepRapFirmware does it's delta calibration too.

4 comments to ''Video: Delta Printer Calibration Diagnostics"

  1. Hi, thank you for the video.
    I have a rostock max v2 with Duet WiFi and DC42 ir probe.
    i did the test as you presented and from 3 tests i got mean of 0.011, 0.013, 0.014 and deviation of 0.071, 0.074 and 0.075 after calibration of 13 points i cand any better than deviation of 0.075. Any suggestions?

    1. Jerek, the Rostock Max is one of the printers I mention that displays the "taco" effect. Look at the sequence of probe Z height offsets. Do you see a pattern that goes high-low-high-low (or low-high)? I would guess from your very low mean and high deviation that this is indeed the case.

      The only remedies I can suggest are:
      decrease the outermost probing radius by 20mm and rerun. The taco effect lessens nearer the center of the bed.

      implement probe offsets (H parameter in the G30s)

      use grid compensation (but your grid map is going to look terrible)

  2. Should have dome my work before asking you, i have corrected for difference in trigger height of the IR probe at each point and now i have really good results. I have made really simple excel table, trigger height at test point- trigger ar x0y0-Z offset at reigger point(TH-Thx0y0-Zdelta00) .The only thing left now is to figure out why in certain spots nozzle ends up higher or lower depending on the direction of the movement. i guess it has something to do with my carriages and belt tension. Now i get deviation of about 0.045, not ideal but close enough to to print stupid stuff.
    Thank you so much for all your knowledge and sharing it.

  3. Thanks Jarek and thank-you very much for supporting me on Patreon! It is greatly appreciated.

    You understand it - anytime you observe movement anomalies dependent on the direction of travel, you very likely have some sort of backlash (aka slop) in the motion mechanics. Places to look:

    Make sure the stepper pulleys are secure, they do have a tendency to loosen over time
    Make sure all 3 belts are tensioned and tensioned uniformly
    Make sure the upper pulleys (or where ever the pulleys opposite the steppers are) are not wobbly and the belt does not move side to side as it travels
    Check for belt wear and broken teeth (very difficult to diagnose)

    Try to associate the movement direction with one of the towers. That will usually give you a place to start looking.