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Crash on Y axis detected - no reason to see why  

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TheSlowPrinter
(@theslowprinter-2)
Active Member
Crash on Y axis detected - no reason to see why

It's an on / off problem with my mk3s since ages now. First, it printed without issues for years, now I can't finish one print.

Axis seem to be solid and don't move, print looks fine and there are no depositions on the printed piece.

At about 1cm height, the issues starts. Cleaning the nozzle and the print from some drops filament doesn't help.

Restarting immediately crashes again.

What should I check next? 

Napsal : 25/09/2024 2:30 pm
Diem
 Diem
(@diem)
Illustrious Member

If you are having multiple Y crash reports:

With the power off, move the Y axis by hand; is it smooth? Does the resistance stay the same over the whole range?

Clean and lubricate the smooth rods, check they are not damaged/scratched.

Check the idler pulley is not clogged, out of line, or damaged (loosen the belt and try turning it with your fingertip, is it smooth?)

With the belt loose try turning the stepper motor by hand; you should feel the regular steps, but otherwise: is it smooth?

Cheerio,

Napsal : 25/09/2024 8:07 pm
TheSlowPrinter
(@theslowprinter-2)
Active Member
Topic starter answered:
RE: Crash on Y axis detected - no reason to see why

Thanks Diem,

sounds too obvious to have thought about myself! 😀

Will take a look later.

Greets!

Napsal : 26/09/2024 11:58 am
TheSlowPrinter
(@theslowprinter-2)
Active Member
Topic starter answered:
RE: Crash on Y axis detected - no reason to see why

Additional to my original Prusa MK3s, I also have a AliExpress clone. When comparing moving the axis by hand, the clone runs much smoother.

When moving the orig axis, they are moving in little steps. And the Z axis had 2 spots, where it was even harder to move over.

I have then disassembled and reassembled the X & Y axis. Every part (pulleys, steppers, bearings on the rods) on it's own are moving really smooth. Also I have used excellent bearing lubrication (Molikote, but can't remember which exactly) when assembling them.

When putting tension on the belts, the free running pulleys run smooth, but the steppers not so much. I really hope they aren't broken.

Let's see how the next print goes, after belt adjustments.

Napsal : 27/09/2024 10:03 am
Diem
 Diem
(@diem)
Illustrious Member

but the steppers not so much.

You should feel the steps but no grating, no roughness. 

Cheerio,

Napsal : 27/09/2024 11:23 am
TheSlowPrinter
(@theslowprinter-2)
Active Member
Topic starter answered:
RE: Crash on Y axis detected - no reason to see why

Have now printed a part, a bit higher than where the crashes happened. Always focused on the print head.

Looks like there was some dirt in the belts, as nothing else has changed than everything disassembled, tinkered around and assembled again.

What I still don't understand: Why it only started to happen on layers above around 1cm? The nozzel doesn't touch the print, so there is no torque involved, which could increase on higher layers. ¯\_(ツ)_/¯

Just forgot to turn on crash detection again for this print. Next one will be with detection on. This will tell if everything is fine again.

Thanks once more for the hint @diem.

Napsal : 30/09/2024 7:19 am
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