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Massive miss alignment mid print  

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torbenberger
(@torbenberger)
Active Member
Massive miss alignment mid print

I just tried my first bigger print on the XL. Only using tool 1 of 5, so no tool changes involved.

Looks like the printer just decided to print somewhere else mid print, any idea what could cause this?

Firmware & Prusaslicer are on newest version.

(also the print did not come loose on the print bed, it sticks really well)

 

This topic was modified 4 months ago by torbenberger
Posted : 14/12/2023 2:28 pm
torbenberger
(@torbenberger)
Active Member
Topic starter answered:
RE:

happened on the same print again in the exakt same way.

happens around 1:00 in the following video, seems like a big positioning issue, the print head just runs into the wall and from there on the position is wrong.

https://drive.google.com/file/d/1eD_Nbe_Mc5ENBOsI_FIAxc_7O632iXad/view?usp=drive_link

This post was modified 4 months ago 5 times by torbenberger
Posted : 14/12/2023 5:42 pm
ntdesign
(@ntdesign)
Reputable Member
RE: Massive miss alignment mid print

There seems to be no reason why it should skip steps, since the footprint is the same on all layers and the head movement looks smooth (so no collision with the model before it hits the wall). If it always happens at the same height, maybe corrupted gcode? Try reslicing and a new flash drive?
But anyway it should detect a massive crash like that and re-home itself. This could well be a firmware issue, I would contact support and definitely keep the sliced file in case they need it.

Posted : 15/12/2023 10:13 am
torbenberger
(@torbenberger)
Active Member
Topic starter answered:
RE: Massive miss alignment mid print

Thanks for your reply.

It's not happening on the same layer, also resliced the model with couple of settings, always with similar results somewhere down the print.

I then tried the non-input-shaper preset. As it turns out, crash detection is disabled with input-shaper profiles. With the non-input shaper, the printer actually detects some crash. It seems i have a slight bend in print on which the printhead catches from time to time. As this is not detected at all, the printer just completely looses correct positioning and from then things go south.

I would really highly recommend to NOT USE THE INPUT SHAPER PROFILES!!!! I can't state this enough. If there is really no crash detection at all, this might lead to some serious damage to your printer. On the github issues section some users are reporting similar things. When you mix things with multi material, you might even have the printer crash toolheads into parked ones while attempting to change.

tbh this should be marked with a big disclaimer everywhere you use input shaper even if it was an alpha firmware. This should never be marked as stable as it is, BC IT IS NOT STABLE! shame on you prusa!

Posted : 15/12/2023 12:14 pm
ntdesign
(@ntdesign)
Reputable Member
RE: Massive miss alignment mid print

And where does the bend come from? Did it detach or warp?

Posted : 15/12/2023 12:20 pm
torbenberger
(@torbenberger)
Active Member
Topic starter answered:
RE:

Its a 40cm long 3cm wide piece. The print slightly detaches on the edges => first mall crash. Then it warps somewhere in the middle (without detaching, bed adhesion is good) => second to n-th crash.

This is an XL printer, so you print large stuff which comes with it's own challenges like bending / warping. So crashes are somewhat expected from time to time which is totally fine. But knowing this, you should not encourage users to use a firmware / preset that seriously damages your (3-4k €) machine when it encounters expected crashes.. thats just really not okay to say the least 

This post was modified 4 months ago 2 times by torbenberger
Posted : 15/12/2023 12:24 pm
ntdesign
(@ntdesign)
Reputable Member
RE: Massive miss alignment mid print

Agreed. They should at least stall the motors when encountering resistance above a certain threshold (some minimal crash safety).

Posted : 15/12/2023 1:01 pm
kmkeller
(@kmkeller)
Member
RE: Massive miss alignment mid print

We are having the same issue on our 2 tool printer

Posted : 02/04/2024 9:10 pm
teleporteur
(@teleporteur)
Member
RE: Massive miss alignment mid print

I have exactly the same problem, it only happens on pieces of size like the photo in the first post

If I print a shorter and taller piece, even for 6 hours, this problem does not happen!!!

And when the head shifts to the right we hear a loud noise at 1-2 motors. Then the head hits the rail on the right and automatically the head falls on the plate because the 2 pieces which hold the head on the carriage slide to the left!!!

The piece that I print does not lift at all and there is nothing wrong with it.  So no obstacles !

I am extremely disappointed with PRUSA

I'm waiting for a response from support

Posted : 08/04/2024 8:45 pm
Diem
 Diem
(@diem)
Illustrious Member

The two unsupported curves are warping upwards, there's your crash.

Cheerio,

Posted : 08/04/2024 11:27 pm
teleporteur
(@teleporteur)
Member
RE: Massive miss alignment mid print

No, that's not the problem, it's not warping, the object is made like that, see my new image, the problem appeared on the 1st 2nd print much higher up!!!

This is a serious problem with APs stepper motor management.

 

Posted : 11/04/2024 7:45 pm
AsmodeusVirolac
(@asmodeusvirolac)
New Member
RE: Massive miss alignment mid print

I have this Problems too.

I have tried as a temporarily solution to slow down printing-speed via the printer menu to 90%. That helped.

From what i have viewed when it happened, the problem is the following:

The xy-movement speed for travels is extremly high and the z-movement couldn't move fast enough/don't do enough movement to get a safe z-distance.

Maybe increasing the ramp-angle for the travel-lift might help. But couldn't try it myself for now.

Posted : 12/04/2024 7:50 pm
AsmodeusVirolac
(@asmodeusvirolac)
New Member
RE: Massive miss alignment mid print

it is definatly also not a warping issue, as i also had the problem with PETG-CF with less than 0.08% shrinking.

My suggestion at the moment is, that it might be a problem of a the bed-level ...

That what i want to test, if my bed might have  a hight difference from back to front, because (regarding the standad-profile) the max travel-lift is 1,5mm with an ramp-angle of 1°.

 

Posted : 12/04/2024 8:03 pm
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