Prints shifting on TAZ 6

General LulzBot TAZ
1

I have a TAZ 6 that over the past couple weeks has started shifting midway through longer PLA prints. I have been trying to troubleshoot it using info from various sources, but so far, no luck.

A few details on my TAZ 6 and things I’ve tried:

  • It is less than 2 years old - most prints I do are 6 hours or less. I don’t run it 24/7 at most a few hours a day and there is not a lot of wear on the machine (looks new).


  • It is in an enclosure - however the electronics have air pulled in from outside the enclosure. I have a thermometer inside the electronics chamber and it stays 65-70F when printing. I also added heatsinks to the top of the driver chips as a troubleshooting step (assuming Y driver was overheating).


  • In addition to the electronics chamber, I have a thermometer inside the enclosure - temp is normally 65-70 and I leave a couple doors open when printing PLA.


  • I mainly use PLA and haven’t tried any other material - trying to fix it with PLA first.


  • It seems to only shift halfway through prints over 4 hours.


  • It is always the Y Axis that shifts (see attached image).


  • The size of the part doesn’t make a difference: ie I’ve printed things as small as filament clips and it will still shift.


  • I did a 16 hour print a week ago and it did NOT shift - not every print shifts.


  • I’ve checked the stepper motor, shaft set screws, belt tension, and as many mechanical things as I could think to check - all seems ok.


  • The issue happens with brand new filament rolls that I know are not tangled.


  • Most 2-3 hour prints do not shift.

Before I start replacing stepper motors and Rambo boards, I wanted to see if anyone here has any further ideas I could try.

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2

Looks like I’ve been searching the forums for the wrong terms. I found a couple posts on “misaligned printing” and “stepped and jagged printing” that showed similar issues to mine. Piercet suggested checking the Y-Axis belt which I am embarrassed to say I didn’t think to check. Tonight I flipped over my printer and my Y belt did not make a “guitar pluck sound.” In fact, every single M3 screw under my printer was loose. The Y belt may have been tight at one point, but with loose tension screws I am not surprised it came loose.

Everything is tight now, and I was able to play stairway to heaven on my X and Y belts. Hopefully that solves the issue.

3

Thank you for this post. I’ve been having this same problem with 8 hour prints :cry: and it keeps getting shifted off the Y axis. I currently paused my print to check the tension to find the screws could use some tighten. When the print is finished, I’ll check the motor pulleys and all other axis to ensure all are tight.

4

If all the mechanical parts look good, you can reduce the y acceleration and see if that helps. We have had several Y drivers fail on the Rambo. Sometimes, the first indication of the driver starting to go is an occasional offset.