4 replies

Layer Shifting After ~20 hours

motion

Hi everyone,

I'm running into persistent layer shifting about 20 hours into a 23 hour print. I've tried the print about 9 times now, and only one of them has finished.

Details worth mentioning:
The shift is always similar in size (about 20mm)
The shift happens at nearly the same height, but not exactly. If I'm printing in IDEX mode, one will shift before the other
The shift is one sudden jump
After the shift, the belts and pulleys are in the same alignment as before (in other words, the belts are not slipping)
There are no error messages in the console.
Only rarely have I seen it shift early in a print (could have been a different issue when it did)
Shift usually (but not always) occurs in just the X axis
I don't really have the same problems if I print the same file but faster. For example if I use PLA instead of PLA silk, it's much more likely to finish.
Stepper motors are steady at about 55deg C
Earlier I was getting an error message that the rpi was being undervolted at times, but that has since been fixed

Things I've tried so far:
Decreasing accelerations (I'm at about 6000mm/s2 for travel moves)
Increasing current to stepper motors from 1.6A to 1.8A
Decreasing the current to steppers to 1.5A (I'll probably try decreasing by more today)

None of these things seemed to produce any change in success.

My setup:
Mostly stock Vcore 4 500 with IDEX. I'm powering the RPI on it's own buck straight from the PSU and the only other addition really is some chamber lights. I've attached my printer.cfg.

Current hypotheses
Thermal issue with the drivers
PSU instability or transient power drop

If anyone else has had similar issues or has any ideas on how I can go about debugging/fixing this, I would love to hear them! Thanks in advance