So finally I managed to assemble the printer. But all my testprints of Benchy and a Lowrider Benchy look a bit strange.
In Cura all models look normal.
The magnetic plate is fixed with clamps and does not shift during the print.
Where is the mistake?
Trimpot adjustment should only be made with printer powered off. If adjusted whilst powered on, especially with a metal screw driver, the board will get fried.
I am not very satisfied with this printer and my negative post was deleted. What happened was that all 3 trimpods went up in flames when I adjusted them. Thus in my opinion this printer never should be used unattended. So its useless for me and went to the junkyard. An expensive experience for me.
@st-blum did you ever solve this problem? I'm having the same issue but on my y axis instead. I think my driver trimpot was adjusted incorrectly and killed my stepper motor. I ordered both a new driver board (as making fine adjustments made no difference by the time I tried fixing the problem) and a new stepper motor as I think it killed mine. Hopefully it fixes it
Besides mechanical resistance on the platform, adjust your stepper driver trimpot, it's possible that it may be supplying too much current to the motor, causing it to over heat and temporarily shutdown before cooling again and becoming active. Vice versa you may not have enough current going to the motor and causing it to struggle. You should only need to adjust it very slightly as the tmc2100 trimpot is a little more sensitive than the a4988 drivers.
Definitely looks like there's a bit too much resistance somewhere on the X-axis. If you push the build axis along with a finger with just enough force to start it moving, it should be smooth right to the end. Eccentric nuts being too tight is one cause. Alternatively my x-axis pulley gear was a bit too low causing a couple sections of biting which gave me the same kind of results with layer shifting along the X-axis. Print speed/jerk/accel could also cause this, but shouldn't be coming into play if you are using default settings.
You can add a Z Hop so the hot end moves up when it moves. Sometimes it can hit the part causing shift. Also, in Cura, spin the model 90deg in XY and try again. See if shift moves or same direction.
Dear St-Blum, I had a similar problem where layers seemed to shift quite a lot during print despite the fact that the flexible printbed was fixed. In my case, the X-Axis belt was fixed to tight so sometimes the printbed did not move at all and sometimes it was kind of jumping after managing to overcome resistence. After loosening the screws on the support wheels my prints came out super smooth! Good look and I keep my fingers crossed this works for you, too. Best regards, Denis