Non-uniform layer shifting or possible magic collision

Non-uniform layer shifting or possible magic collision  

New Member

This is a test print for a nice cylindrical Periodic Table of Elements, and for some reason, when my layer height is set to .15mm, I am getting strange layer shifting, or possibly some strange collisions. The front of the test print is great, but at a certain height as you go farther back, there is a very noticeable failure. When printing with .3mm layer height, there is not shifting, but there are slight issues with the underhang on the upper-side of the hexigons.

Debugging Steps Already Taken

As the weather got colder, I found several of my prints becoming more Salvador Dali-esque. I re-lubricated the rods and loosened the belts, and the prints resumed semi-normal functionality. However, I'm not able to get anywhere near the proposed .05mm layer height anymore... Spaghetti monsters abound. 

Multiple prints are displaying the same failure in approximately the same location.

My Ask For Advice

Any idea what would cause this so uniformly and where I should continue debugging?

This topic was modified 7 months ago by SwingChef
Posted : 08/11/2019 3:51 am
Famed Member

Bit of a long shot, but there is (or was?) a bug in a recent firmware release that caused problems when the filament sensor was enabled. You might try disabling it and trying again. I saw it as layer shifts and errant lines on the 2nd layer. I looked random until I realized the shift was identical with each print.

I'm getting an error on your link. Can you save a project (3MF) file, zip it and upload it here?

This post was modified 7 months ago by bobstro
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Posted : 08/11/2019 2:51 pm
New Member


I realized that I had the wrong link in my buffer when I pasted it. This is the correct Thingiverse link:

I hadn't heard about others having issues with the filament sensor; I honestly thought I had broken mine somehow, and had turned it off until I had time to debug it. I just barely updated the firmware (from 3.8.0 to 3.8.3), and it seems the filament sensor is still causing issues. At least, when trying to print the 19-minute test Prusa plaque, the filament sensor exhibited 2 false positives in the first two layers. Having updated the firmware, I'll do another test print of the helix base to see if that makes any difference.

I was thinking of additional calibration on the Z-axis, but it seems like that would be causing additional problems elsewhere on my print.

Posted : 09/11/2019 4:21 am
Honorable Member

i suspect your filament sensor needs a tiny adjustment,( hardware not firmware). it sounds like it's triggering very close to 1.7mm and needs to trigger around 1.5mm



Posted : 11/11/2019 6:32 pm

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