Print failing at exactly the same layer(s)



  • Hi all,

    So, the background is: my printer is a custom build core-xy d-bot running firmware version 1.19.2, my belts are tight, the motors are strong enough that i can't physically move any axis when they're engaged and everything is well calibrated, moves smoothly and does not catch in the movement path.

    The print in question can be found here https://file.io/crxbfU

    My issue is this:

    https://i.imgur.com/CvYwhh1.jpg

    for some reason, at exactly 104mm on the Z on both failed prints i have it shifts in the exact same direction by the exact same amount, i haven't been present at the point or after the shift to try figure out why, annoyingly this is pretty much all i have to go on, the entire rest of the print is perfect and the edges of the top of the print are cooled adequately and thus do not curl up, catching in anything. The weight of the print on the z does not affect it, i can push very hard and the bed will not move when motors are engaged. I have tested moving the x/y quickly back and forward at speeds greater than what i'm printing at with no issue.

    I want to say this is a software issue due to the fact it failed at the same layer, in the same way, but i'm honestly not sure, any help would be appreciated.

    Thanks,
    Declan


  • administrators

    If it's a firmware problem then there should be a nonzero count under "Step errors" in the M122 diagnostic report after the error occurs.

    However, your print has a large overhang. I strongly suspect that you are getting curl-up at the edge of the overhang, and the nozzle is catching on it.



  • That's what i'd like to imagine but the inner face has a consistent 45 degree angle all the way up and the back face of the edge is perfectly smooth, the top also doesn't really curve at all as it's PLA and cooled fairly strongly. I'll keep that gcode in mind if i attempt this again, thanks



  • Actually, that's a really weird picture because the shift seems to be both positive and negative in both X and Y. It's almost as if several layers were not printed at all, then it resumed with those 3 inner parts being printed at a larger diameter because several layers had been missed, but also with the entire thing rotated. The link to the file seems to be broken but I'd suspect the actual gcode file is corrupt. Take a look through it and see if you can spot anything going weird at around 104mm. Look for the maximum X and Y values suddenly getting larger compared to previous layers.



  • Ah, sorry about that, here's an amended link: https://drive.google.com/file/d/1qiS-JFY-y8D6g8poORKAAcmqyTzxZ1rE/view?usp=sharing, I've ran the file through several gcode readers and it doesn't seem to be doing anything too untoward at 104



  • Load it in your favorite slicer and drop it under the bed until 100mm mark and attempt to print just that part.



  • I appreciate all the above suggestions, however, as you probably all assumed and much to my chagrin, it was a model/hardware issue combined with a bad config. Basically my setup is a chimera and my bed has a 1mm bow from the left to right, i'm currently using mesh levelling with it tapering off at 1cm, i think the taper and the curve of the bed is affecting the print because the other nozzle, whilst it works fine for most parts, can hit a piece of the model whilst travelling.


 

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