Weird layer shifting

[Emrea 0]

I have weird layer shifting that always happens in the same direction the same amount each layer, it looks like a software issue because it's way too consistent.

 

I have a sketchy looking printer I made on my own, I just have gotten it up and running with marlin. I printed over usb with Cura, the preview did not show this.

 

Any tips?

Edited June 10, 2020 by Emrea

[gr5 2,172]

It's the printer, not the gcode.  There is some fast/violent move that is identical on each layer and you are losing one full step on the stepper.  It's the same on every layer because it's exactly one full step and because the slicer is doing the same fast move on each layer.

 

It's probably the stepper.  If it was pulleys then it wouldn't be so consistent.

 

Either adjust the current or more likely, lower the acceleration and jerk.  Try cutting them both in half.  You'll have to play with these values.  Hopefully you have a firmware that lets you change this easily for example with a gcode and you can do many moves with higher and higher accelerations to see where it slips and then maybe cut that value in half.  Same with jerk.

 

I'd use pronterface or similar so I can command the fastest possible moves and just do simple, long moves back and forth adjusting max speed, accel, jerk settings.

 

Anyway also it's possible a pulley slipped.

 

If you have pulleys and belts then tighten the set screws more.  You need to tighten the hell out of those set screws - your allen wrench should be twisting a little.  If you have a tiny L shaped wrench then it should hurt your fingers.  Usually the pulley on the stepper.

 

Pay attention to if it was slipping in X or Y as that's the only axis you have to tighten.

 

It's also possible the belts are so loose they slipped a tooth.

 

 

 

[gr5 2,172]

The nice thing about printrun/pronterface is that you can issue gcodes manually and adjust these values and issue G commands to move the axes.  I think M500 can save the acceleration values permanently (so you don't lose them on power cycle).  You should also keep good notes and maybe edit Configuration.h so that if you ever do a "reset to factory settings" you don't lose your hard work.