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markus.z3
(@markus-z3)
New Member
layer shift problems

Hi all,

I assemble my Prusa i3 Mk3 Kit last week and it went really well. Initial Setup and calibration where perfect. The first print came out perfect. Then I start to run in layer shift problems.

I followed KB Article https://help.prusa3d.com/l/en/article/qiPUfukPVw-layer-shifting

My first Belt status was x 291 y 278 so I try to increase the tension of the belt and was able to move it one more tooth. I tighten the motor pulley screws and loosen the idler pulley screws.
Now my Belt status is x 267 y 275 but I have no idea how to get it to 240 or lower.

The first two Benchys are the gcode from the Prusa SD Card printed via my Raspberry Pi.

No 3 is printed directly from the SD Card. Then I sliced the Benchy in Prusa Control and printet from the SD card, this print is much better but there is still an error at the same layer. No5 is agine the Benchy from the SD Card. All are printet in PLA the first shift is always at around 7 mm the second one at 22 mm.
I was able to print some parts like a new Einsy housing or an Alchohol Wipe Dispenser but not without one or two misprints. And when I try to print in PTEG it is even worse.
Firmware is 3.2.1-576

Posted : 30/06/2018 1:33 pm
Asraff Amzani
(@asraff-amzani)
Estimable Member
Re: layer shift problems

Hi,

Try to follow steps 33 of this link https://manual.prusa3d.com/Guide/2.+Y-axis+assembly/507?lang=en

When fitting the y axis belt, make sure the idler has gaps between the metal brace, then you slowly tighten both screws.

X axis however on steps 11 https://manual.prusa3d.com/Guide/4.+Z-axis+assembly/509?lang=en

If your x motor mount is an older design, you can use the mk2's technique which is step 20 https://manual.prusa3d.com/Guide/4.+Z-axis+assembly/296?lang=en

My belt tension stat is 261/260, had no problems printing the benchy with a slightly modded mk3 slic3r profile (I only changed perimeters and skirt count) and printed correctly. The belt tension stats doesn't have to be lower than 240. it is between 200-280 is advised while 240 being the balanced tension vs current for the motor (I think).

You can refer to this handbook at page 72 https://www.prusa3d.com/downloads/manual/prusa3d_manual_mk3_en.pdf

Posted : 30/06/2018 3:13 pm
markus.z3
(@markus-z3)
New Member
Topic starter answered:
Re: layer shift problems

I followed this step. The belts are installed correctly.

Update
After switching off crash detection. It got much better.
There is only a minimal layer shift at 7 mm high.
Is crash detection not working?

Posted : 30/06/2018 4:45 pm
Asraff Amzani
(@asraff-amzani)
Estimable Member
Re: layer shift problems

I would still advise you to tighten the belt even more.

There's a lot of problem with the crash detection as of 3.2.1. I personally turned off crash detection because it is a false positive crash. Printing a benchy alone can have up to 35-40+ false crashes while after turning it off, the benchy printed perfectly without layer shifts.

Usually minimal layer shift can also because of your belt tension and motor pulley not tightened properly, the grub screw i mean.

Posted : 30/06/2018 5:21 pm
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