I recently Klipperized my SV06+ and smaller prints haven’t been having an issue, it’s been great. However larger prints seem to have one-off Y-axis shifts in the same direction every so often:
(this particular print was done overnight, which is why I didn’t stop it)
I checked the belts and bearings, re-calibrated input shaping, and watched the print. I also made sure the power cable isn’t catching (I have a mod on to raise it out of the way). It doesn’t seem to have any specific errors or breakdowns when the axis shifts, it just does it then moves on. It didn’t have this issue on Marlin, and haven’t really tweaked very much so far. The only possible thing I can think of is that I’ve set stealthchop_threshold to 999999 on the Y axis stepper because it was loud as hell following Klipperization (which worked to quiet it down).
First it didn’t happen with Marlin because you were printing a lot slower.
Four things can usually cause this…
1: Layer Adhesion, not your problem.
2: Debris on the Z Rod if it seems to be happening around the same point in the print.
3: Loose Y Belt tension.
4: The Nozzle hit the infill.
I ran a test print on three cylinders that are taller than the first print (printed one at a time) and it didn’t run into any issues, so it can’t be 2. We know 1 isn’t it. The Y belt tension is taut and hasn’t loosened, so it’s not 3. And 4 would only make sense if the print had lost adhesion from the bed and shifted, but it didn’t.
I’m running a test print of the same part again, but this time rotated around the Z axis by 45° and seeing if that helps. I’ll try to reproduce the issue on something else tomorrow.
Then you have tried two different brands of filament. Unless they bother are unusable (not very likely IMHO - I routinely print with old, brittle PLA filament without trouble) the problem is elsewhere.
Is the printer placed on a stable surface? Or does it shake around a lot when printing?
From that picture, it looks like your printer is really close to the back wall.
If you push the plate all the way back does the cord hit the wall…??
I’m not talking about the cord getting caught under the bed & frame, but the cord pushing against the wall.
With the bed all the back, you should leave about 2" of space so the cord doesn’t hit the wall.
This could be why you problem is so intermittent, if the cord is hitting the wall…it could be enough under certain conditions to cause your layer shift. Since your running Klipper, it could be a significant bounce off the wall…JMO
The cord never hits the wall. I put in the OP that I have a clip on the cord specifically to reduce that chance. All the way back there’s about 3 cm of clearance.
Did you have this issue before you added the cable support…??
From you make, it’s only been installed about a month.
have you considered removing one or both pieces to see if this is an issue…??
I saw another make where a user posted that he had to remove his because it hit a stepper fan he installed.
In your 1st pics the shift is forward, in your last pic the shift is going backward.
It’s nothing we’ve checked so far, not the belt, not a mod, not speed, not a slicer issue.
So, unplug the printer & move the bed back & forth & see if you can feel anything through your fingers…a bump or sudden stop or catch.
Check the grub screw in the stepper gear…make sure it’s tight & the shaft doesn’t wobble.
Check for a piece of filament on the belt or in the stepper gear…(I just had this happen on my ACE)…also check the gear in the front adjuster. To do this properly your going to have to move the bed & a forth to see if their is anything stuck along the belt path, filament, hair, etc.
Look between the bed & the frame while moving the bed back & forth to make sure nothing it hanging down or stuck on the rails.
Plug the printer back in & using the screen, move the bed back & forth & listen for any clicks or noise that doesn’t sound like the normal bearing noise.
Well, at this point I’m at a loss…
to me it just keeps coming back to either the nozzle hitting the print or the belt is loose.
It couldn’t hurt anything to tighten it 1/2 of a quarter turn (1/2 of 1/4).
I’ve adjusted the belt a few times, and the issue persists. It actually gets worse when I adjust too far in either direction (likely compounding issues), so keeping it where it is seems ideal for now.
As a stopgap, I’ve dropped the speed factor to 50% across the board, and that seems to alleviate the issue… but it still doesn’t tell us what the issue actually is nor how to fix it so I can print at full speed again.
