Crashes detected in Y-Axis without apparent reason. Resulting in layer shifts.

Crashes detected in Y-Axis without apparent reason. Resulting in layer shifts.  

Active Member


My Prusa i3 MK3S ist working really fine, and most of the time it prints with no issues and I get perfect results. 

There is one small issue I have: The printer frequently detects crashes in the Y-Axis with no apparent cause. Usually, this is no huge problem and just leads to minor imperfections. Yet, I had a visible layer shift, around 0.5mm, after such a crash detection (printing PETG).

I tried to find the cause for these detected crashes:

  • Lubricated the rods and bearings.
  • I checked for any plastic parts on the belt.
  • Checked if the pulley is fastened. 
  • I removed the belt and re-assembled it, checking the belt tension values. The measured value is now around ~270, it was higher before ~250.
  • Recalibrated everything.

This had no effect, in the last print, I had again 3 crashes detected in the Y-Axis.

If I understand this correctly, disabling the crash detection will ignore these crashes but may generate layer shifts?

What else can I do?


Posted : 24/09/2020 10:28 am

does the axis move freely by hand?

could your ubolts be too tight?

could your idler bearing bolt be too tight? or the bearing be faulty?
could the motor pulley be rubbing against something?


regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK...
Posted : 25/09/2020 6:03 pm

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