Why would my Delta do this?



  • Please watch the video I have uploaded to my Google Drive: https://drive.google.com/folderview?id=1mMQUQU7hyqLuA7Hmn7ylKW_2XPX-9gX6

    I am not in possession of this machine, I built this for a friend of mine and he is trying to print a 110 mm diameter cone out of translucent petg. I almost suspect the "B" parameter in the M665 in the config.g is to blame for this, but would exceeding the printable radius in this line result in such erratic behavior??

    I'll get the gcode file and his config.g in the morning, what happens when you exceed that limit though??

    If printed within the 100 mm diameter "limits" parts print BEAUTIFULLY and precisely. A hair over what he calls the "calibration circle" (I assume printable radius) and all hell breaks loose. I am assuming "B50" is what I'll see in his M665.

    What are your thoughts?


  • administrators

    You have not performed delta calibration, or if you did perform it then you didn't save the results. See https://duet3d.dozuki.com/Wiki/Calibrating_a_delta_printer.



  • @dc42

    I thought something similar, would a G28 ; Home after a G29 S1 do this as well?

    I machined the extrusion and measured the rods with pin gages, I know the machine is accurate and the guy using it is a competent programmer and electrical engineer, he is just not used to G-Code. He has a 3D printer but it is running marlin.

    What happens when the gcode exceeds the value "B" Parameter of the M665? It's calibrated accurately and the calibration is saved. It is possible the calibration is not being applied, for example missing a G29 S1 or maybe the G29 S1 is before the G28?

    Forgive me for the late response, had to fly up to NY for business.



  • I've had some parts run over "B". The "outline" is "clipped", meaning a line that would cross "B" hits the limit of the "B" circle, moves along that circle, and continues to move along the circle until the endpoint of a move is inside that circle. The net effect is as though you pressed the part against a hot curved surface. That's the best I can put it into words.

    And... if I understand your question correctly, another way of phrasing the answer: Nothing "crazy" happens.



  • From the video:

    I hear it skipping teeth on the belt. I can't see the bottom mechanical endstops.... but I believe it is hitting these. Also, I see a ton of Z movement that shouldn't be there.

    Please post the entire contents of config_override.g and config.g.


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