Welcome to the SeeMeCNC Community

So in the past few months, my printer has developed a real problem with layer shifting, and I'm just not sure what else I can try that I haven't already. Here's what I've done:

*Tightened belts
*Loosened belts
*Made sure the belt drive pulleys are tightly screwed in and well aligned/not rubbing
*Replaced the 3 year old belts
*Increased motor current
*Decreased motor current
*Increased air flow pointed at drivers
*Slowed down prints
*Decreased acceleration (down to 1000 from 3500)
*Decreased travel speed to 125
*Increased Z hop to 2mm
*Disabled "avoid crossing outline" (simplify3d)
*Swapped control boards...had a Ramps with drivers laying around

Seriously, what else is there? I'm stumped.

*EDIT* My prometheus hotend hangs down from the effector, maybe the mount has developed a tiny amount of wiggle? Gonna try replacing it.

Does the layer shift always happen in the same direction?

g.

Set screws on the pulleys on the stepper motors. You may think they are tight but you may not have one of the screws on the flat of the stepper shaft. Been there, done that and it is hard to diagnose. But since you have done everything else, it's a place to look. And as Gene asked, can you correlate the shift with one of the tower axes? How big is the shift? Is it alway 1 direction or does it go back and forth? Curious minds want to know!

The shifts do seem to happen in the same direction, so I did think it was related to one of the towers in specific, but despite checking and rechecking the set screws on the pulleys, still no improvement. But! Then I wiggled the hotend to try to see if there was any play in the mount, and since then the printer can't maintain layer alignment for it's life...so if that wasn't the main issue before, it certainly is now, hahaha! I have a friend printing me out an extra beefy replacement I designed to hopefully stop this from ever happening again.

Are you using the u-joint arms by chance?

g.

I just upgraded to the new ball-cup arms, around 6 months ago. They are fantastic. ^_^ Turns out the issue was in fact that the printed piece I was using to mount the hotend to the effector had developed a teeny bit of play, and with the replacement the layer shifting seems to have cleared up. I just wish I'd thought of that sooner! *facepalm*

Glad you got it sorted.

g.