Layers Shift on the X axis

General Discussion
1

Printer Model: UlTi Steel v1 (Ultimaker kinematic)
MCU / Printerboard: SKR v1.3 + Raspberry Pi 3B+
Drivers: TMC2208 without UART
klippy.zip (1.8 MB)

Hello,

I have a problem with shifting layers on the x-axis. The shift is always only on the x-axis.
The problem appears periodically, the printer prints normally for a couple of days, then problems may begin.

photo_2022-10-26_20-49-05
photo_2022-10-26_20-49-051280Ă—960 212 KB

The print head moves to the side smoothly, there are no jerks.

What have I done:

  • Rechecked the mechanics
  • Changed currents (now 1A), added cooling, does not help.
  • Swapped the motors of the X, Y axes, the problem remains on the X axis
  • I changed the drivers to new ones, swapped the drivers for the X, Y axes. The problem didn’t go away.
  • Updated klipper
2

Hello @Nyrlan17 !

You may try with reduced acceleration and velocity.
Also check for smoothness of the x-axis and that the belts are not too tight but also not too lose. It seems, you have some of them.

3

thank you @EddyMI3D
I think the problem is not in the mechanics, I checked all the mechanics.
The displacement is smooth, as if these movements of the print head are written in gcode.

photo_2022-10-26_20-49-59
photo_2022-10-26_20-49-591062Ă—771 146 KB

It happens that the print head moves continuously along the X axis until it stops. After that, the engine starts to skip steps and make characteristic sounds, as there is nowhere to move.

Сhanging acceleration and velocity doesn’t help

4

The most likely problem is that your belts are too tight or too loose with a secondary problem being that you have a pulley that is slipping on the shaft.

I realize that you looked at the printer’s mechanics but I would suggest that you do an experiment with the belts loosened slightly and then one with the belts tightened slightly from what you had originally.

If it is a belt problem, one of the experiments will be worse and one better.

Good luck!

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5

Just a couple of other things to consider in addition to the other excellent suggestions:

  1. I see that you have increased stepper current to 1A. In the background of one of your images, it looks like you are running 40mm steppers. 1A is usually at the lower end for a 40mm stepper, most seem to be rated at 1.7-2.0A, so I would try 1.2 or 1.3A and see if that makes any difference. Ideally, check the ratings for your specific steppers. Also, don’t specify a hold current for X and Y axis, it’s unlikely to ever be used anyway so better not to specify it

  2. Whenever I get x-axis layer shifts, it is almost always caused by little blobs being left on top of the print before a retract/travel movement. The next time the head travels over the blob, it smashes into it, and that causes the stepper to skip steps. So consider adding Z hop of 0.5mm to 1.0mm and see if that fixes the problem. This will slow down your print times a bit, but just do it to see if it fixes the problem, and if it does, then you can look at fixing the cause of the blobs. This might include tuning print temps, retraction settings and travel settings, but they can also be caused by the filament curling up when printing large overhangs.

1 Like