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I get crash detections all the time  

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Zombatha
(@zombatha)
New Member
I get crash detections all the time

Hi

I have been unsing my MK3 Kit for 2 - 3 weeks now and it has been working fine.
The z-axis has been somewhat noisy all the time but I believed it to be due to resonace in the construction itself.

Now however the z-axis has begun to miss steps and the z-axis noise has become far louder. I believe that the
electronics is failing. The printer detects some of the missed z-axis steps and makes a crash-detection reset,
but after a while is looses the orientation completly and begins to print completly wrong.

I'm very carefull with ESD and always uses ESD protected desk mat and wrist strap when I work with electronics.
However the controlboard could stil have got damaged somehow.

Do you have some troubleshooting tips? Otherwise I would like to get a new board sent to me for replacement
to see if that can solve the problem.

Postato : 29/04/2018 9:04 am
RH_Dreambox
(@rh_dreambox)
Prominent Member
Re: I get crash detections all the time

Make sure both trapezoidal nuts run smoothly on the motor axles. Lubricate the Z axes with Lithium grease (or some sewing machine oil).
Make sure that the two Z-screw covers are not tightened, then they may cause malfunction.
I don't believe in electrical or electronics errors.

Bear MK3 with Bondtech extruder

Postato : 29/04/2018 9:58 am
darKing
(@darking)
Trusted Member
Re: I get crash detections all the time

Also make sure that nothing is blocking the z axis. I have my raspberry attached to the z axis and at some point the USB cables an / or power cables got tangled around the z axis motor and it could not move freely up and down 😁

Postato : 29/04/2018 12:04 pm
Zombatha
(@zombatha)
New Member
Topic starter answered:
Re: I get crash detections all the time

Thanks for the tips.

The z-covers are running freely, (always have).
The screws are lubricated, they were lubricated, but I added some more.
There are no cables or other stuff jamming or blocking the z-axis (never have been).

Still no joy!
Still crash detections and loosing coordinates after crash recovery.

ehum, should have mentioned in my first post that the prints starts as they should
but after a couple of layers I begin to get crash detections

Postato : 29/04/2018 5:29 pm
moggieuk
(@moggieuk)
Eminent Member
Re: I get crash detections all the time

Hi, one more thing to check is that your y-axis belt is sufficiently tight. Also, try printing in stealth mode. If you get good prints without missed steps then I think you are experiencing the same over sensitive crash detection on the y-axis. If have the same problem and I know my bed glides perfectly without any form of binding -- without a belt, tipping the machine a few degrees causes the bed to slide from end to end. My bed also resonates and I notice a little play if I shake it left to right.

Anyway, I have had some luck by decreasing the sensitivity of the y-axis crash detection. To do this you need to put the following in your g-code start script:

M916 Yx

Where 'x' is a number from 3 (the prusa default) to 63. Higher number is less sensitive.
e.g.

M916 Y9

Try M916 Y5, then Y7, then Y9 and so on and see if that improves things.

My only concern with this is that this will decrease the stall sensitivity for homing with **could** mean restarts are less reliable. I've submitted a 'issue' on github suggesting that there should be two sets of sensitivities: one for homing and one for general operation.

Postato : 29/04/2018 9:57 pm
darKing
(@darking)
Trusted Member
Re: I get crash detections all the time



Try M916 Y5, then Y7, then Y9 and so on and see if that improves things.

My only concern with this is that this will decrease the stall sensitivity for homing with **could** mean restarts are less reliable. I've submitted a 'issue' on github suggesting that there should be two sets of sensitivities: one for homing and one for general operation.

Not sure why this should help with his Z-Axis though. 😈

Although I also thought of the Y-Axis thing right away. 🙂

Postato : 30/04/2018 12:02 am
moggieuk
(@moggieuk)
Eminent Member
Re: I get crash detections all the time



Not sure why this should help with his Z-Axis though. 😈

Although I also thought of the Y-Axis thing right away. 🙂

Lol! I've always got my left and right mixed up, so I have no chance with X, Y & Z !!

Postato : 30/04/2018 1:27 am
Zombatha
(@zombatha)
New Member
Topic starter answered:
Re: I get crash detections all the time

Thanks for the tips, again. 🙂

I deactivated the crashdetection and got a good print.

I will test to slightly change the sensitivity for crashdetection of the y and x axis.

Also I came to think about the material (in this case PLA) its pretty stiff and if the print causes a small bump or something gets a little bit bent during print it may cause a crash detection (perhaps. a wild guess from my side).

So I will do some testing with the orientation of the stuff I print and how the support is printed.

Thanks again

I'm glad that the electronics seems to work well.

Postato : 30/04/2018 12:53 pm
darKing
(@darking)
Trusted Member
Re: I get crash detections all the time


Thanks for the tips, again. 🙂

I deactivated the crashdetection and got a good print.

I will test to slightly change the sensitivity for crashdetection of the y and x axis.

Also I came to think about the material (in this case PLA) its pretty stiff and if the print causes a small bump or something gets a little bit bent during print it may cause a crash detection (perhaps. a wild guess from my side).

So I will do some testing with the orientation of the stuff I print and how the support is printed.

Thanks again

I'm glad that the electronics seems to work well.

So uhm... are you actually talking about your Z-Axis (up / Down Axis) or not? 😀 I revisited my failed stats menu and realised that there are no Z-Axis crashes. So I guess you got it kind of wrong in your first post. ❓

Postato : 30/04/2018 7:46 pm
Zombatha
(@zombatha)
New Member
Topic starter answered:
Re: I get crash detections all the time

Well, the printer reported z-axis problem, and while moving up and down it sounded pretty loud.
Adding lubrication to the screws seems to have solved that problem. It still sounds and vibrates a litte bit too much but I will take a good look att the screws and the bearings to see if I can make them run more smooth.

The reason I believed it to be a problem with the electronics was that the Z-steppers sounded as when the drivers failes for some steps. But it seems to have been vibrations. 🙂

I also noticed that sometimes small pieces of the prevous layer are raised a little bit and it looks as if I get a crash detection when the extruder crash into these bits. So I will make some tuning of the crash detections so that it's not too sensitive.

It very interesting. This is my third printer. The very best of them all. But all printers have different behaviours and different symptoms that one always need to get familiar with. 🙂

Postato : 01/05/2018 8:31 am
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