Crash Detection  

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cjarmagost
(@cjarmagost)
New Member

Hello All,

My name is Clayton, my friends call me Ghost. I have a MK 3  that keeps triggering the crash detection. The belts are tight on both axis(ssss). I think it is the nozzle bumping the little bit of extrusion when the head lifts to move to a new position. How do I fix that?

I have read some of the threads and they say to turn off the crash detection, but that seems to me to be the wrong answer. I mean they built the detection to save the printer/print. As a de-engineer that is screaming wrong answer. 

Thanks in advance for your time, Ghost.

P.S. Am I the only one running into this problem?

Posted : 20/07/2019 4:12 pm
joan.t
(@joantabb)
Veteran Member Moderator

Try reducing the flow or reducing the extrusion multiplier, a little!

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 : 20/07/2019 5:25 pm
cjarmagost
(@cjarmagost)
New Member

Thank you for the suggestion.

OK so I am a noob and I did tried to slow down the print to 75% (on the printer as it was printing) . Is that what you are referring to? I do not know what the extrusion multiplier is thou.

Thank you again, Ghost

Posted : 20/07/2019 6:44 pm
joan.t
(@joantabb)
Veteran Member Moderator

the tune menu has a flow selection item, that can reduce the overall filament flow, 

it has a similar effect to changing the extrusion multiplier in the slicer

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 : 20/07/2019 7:54 pm
Tim
(@tim-m30)
Illustrious Member

Folks on the forum can only guess at what you are fighting if you don't at least post an image of a part that is suffering the issue you are concerned about.  Most of us don't read crystal balls or other peoples minds.  And when we do, it is very taxing, especially because of distance.  

Generally, following Joan's crystal ball, if you are fighting curl, slowing down solid infill print speed helps the most.  This is done in slicer settings.  Changing cooling settings in the slicer can also help.  

This post was modified 1 year ago 2 times by Tim
It is always wise to get more than one opinion......
Posted : 20/07/2019 8:24 pm
kisao-lator
(@kisao-lator)
Active Member

Hello all

i have a MK3S in about a week and now that i m done with the first layer calib. i start to print some ready gcodes from the sd

im getting y axis crash detection 

i have check all (i think) possible problems

over tighten bed bearings -belt

i have done the wizard setup 3 times

here is 2 photos of a benchy that get 2 y axis crash and when it resume the print was off the last layer

please tell me how do you see the print quality

thanks in advance

[video width="1280" height="720" mp4="https://forum.prusaprinters.org/wp-content/uploads/2019/07/buddy.mp4"][/video]

 

Posted : 21/07/2019 1:22 pm
Tim
(@tim-m30)
Illustrious Member
Posted by: kisao-lator

im getting y axis crash detection 

 

please tell me how do you see the print quality

thanks in advance

Loosen the U-bolts holding the Y-axis bearings.  They should be snug, not tight. Just enough to keep the bearings in place and not wiggle, basically just "kissing" the bearings, not crushing them.. 

It is always wise to get more than one opinion......
Posted : 21/07/2019 7:04 pm
cjarmagost
(@cjarmagost)
New Member

I have tried all this to no avail. I am starting to wonder about my Prusament. I think I will order some other PLA to try.

I re-tightened the u -bolts, loosened enough to move then just tight enough to stop movement. then printed a Benchy and had 15 crash detections.

I lowered the flow rate as suggested and still have crash detections and I am sitting in the room with the printer and see and or hear nothing wrong. I am losing faith in the product. 

Posted : 27/07/2019 3:28 pm
kisao-lator
(@kisao-lator)
Active Member

I ve done the same exact steps.  Then I just turned off the crash detection and get some flawless prints. I know that this is not the right solution. If the is someone that can give as the right solution. I'll give a try it.

Posted : 27/07/2019 4:48 pm
elad6k
(@elad6k)
New Member
Posted by: kisao-lator

Hello all

i have a MK3S in about a week and now that i m done with the first layer calib. i start to print some ready gcodes from the sd

im getting y axis crash detection 

i have check all (i think) possible problems

over tighten bed bearings -belt

i have done the wizard setup 3 times

here is 2 photos of a benchy that get 2 y axis crash and when it resume the print was off the last layer

please tell me how do you see the print quality

thanks in advance

[video width="1280" height="720" mp4="https://forum.prusaprinters.org/wp-content/uploads/2019/07/buddy.mp4"][/video]

 

OMG! I Had the exact same crash detection at the same place

Posted : 28/07/2019 10:36 am
alexgreet
(@alexgreet)
New Member

I am having the same issue with random y axis crash detections. I initially printed the bench on the sd card and I can confirm that I am experiencing crashes at similar stages in the print. Apart from constant y axis crashes my mk3s prints perfectly fine. any recommendations on how to mitigate this issue besides turning off crash detection? 

Posted : 01/08/2019 3:36 pm
vintagepc
(@vintagepc)
Noble Member

Apparently there's a known bug with false detections in 3.7.2, wait for 3.8

Posted : 01/08/2019 3:52 pm
alexgreet
(@alexgreet)
New Member
Posted by: vintagepc

Apparently there's a known bug with false detections in 3.7.2, wait for 3.8

thanks for the heads up, I was seriously doubting my abilities to get this printer working. Lets hope 3.8 does the trick. 

Posted : 01/08/2019 4:01 pm
wejucook
(@wejucook)
New Member

I hate to admit this but I was getting a lot of y-axis crashes until I looked under the hot-plate and noticed there was still a plastic tie that I did not snip off when un-packaging (I bought mine assembled.)  I thought I was careful and caught all those.  The one under the hot-plate is hard to see!!!

Posted : 02/08/2019 3:45 am
frank.wever
(@frank-wever)
New Member

@kisao-lator

Me too, have the same problem - astonishingly at the precise same positions as illustrated in your picture. This twice times printing the benchy again. And yes - switching the crash detection off and printer is printing fine.

I had tried to fasten and to losen the belts and put some lubricant onto the rods. The y-axis is moving very smooth with little force, this over the complete available length. For x-axis I do need significiantly more force to move it and have no trouble with it.

Now I have no further idea, than to suppose that this behavior (due to the similarity of the crash positions) is a matter of the software. I have updated to the version 3.8.0-2684 for which a crash detection correction was announced in the release notes, but this didn't help either.

So any further ideas?

Posted : 26/09/2019 8:39 pm
Robert-mm200
(@robert-rmm200)
Noble Member

When you are looking at problems like this, remember what a "crash" is. It is not an actual crash - the printer has no way of detecting those.

It means the servo motor resistance has gone up, reason unknown. Practically speaking, it means something has interfered with travel on that axis.

If it fails every time on Benchy at the same level, I would stop the machine right there and see what might be hitting something.

Zip tie is a popular cause. One of the cables hitting something is another. Especially look for drooping cables from the extruder. They should not go below horizontal.

Firmware is the very last possibility I would consider. There are an awful lot of people running this version of the software without reporting problems.

Posted : 26/09/2019 8:53 pm
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