Problem with mk3s pre-assembled; vibrating noise and crash detected
 

Problem with mk3s pre-assembled; vibrating noise and crash detected  

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jon calma.v
(@jon-calma-v)
Active Member

I got my second mk3s just about a week ago and noticed that during bed levelling/calibration before i do a print it makes a very loud vibrating noise. it will still print and work but from time to time, it will hit the x axis and head home with the screen showing crash detected.  at other times, during the calibration before print it already prompts "crash detected" before it even starts printing, and it will just keep on calibrating til it prompts me crash detected and ask if i should continue my prints.

i need this printer to work badly due to my production commitments, but is this issue something i should worry about? any solutions?

thanks,

jon

This topic was modified 5 days ago by jon calma.v
Posted : 25/03/2020 6:30 pm
joan.t
(@joantabb)
Veteran Member Moderator

Hi Jon, 

from what you say, the printer is already working Badly...  I am not sure i can help you make it print worse... 

however I  think there is a chance of making it work better... 

Have you lubricated the linear bearings? 

the X and Y  axis should move smoothly from end to end, without jerkiness, or lots of friction. \

the Mk3 printer senses the motor current, expecting the current to suddenly increase when the carriage touches the end of travel. and uses this to set up 'Virtual End points' 
if the axis jams for any reason, then the virtual endpoints will be in the wrong places.   which can lead to unexpected collisions being reported. 

 other things that can cause problems include 
idler wheels binding because the mounting screws are too tight, 
stiff movement because the belts are too tight,
friction between the motor  toothed pulleys and the mountings, often the X motor pulley is put on incorrectly
wires catching on something. 
Y axis Ubolts too tight,
X axis back cover too tight,
 faulty bearings... 

I hope this helps. 
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 : 25/03/2020 11:04 pm
jon calma.v
(@jon-calma-v)
Active Member

@joantabb

Thanks for the reply Joan.  From what you said, seems like I have really big problem here.  Honestly I know little about troubleshooting issues the printer, the very reason I bought a pre-assembled.   Having said that, shouldn't this printer be tested properly before it was shipped out or at least guaranteed that it will work without issues?

Posted : 25/03/2020 11:34 pm
joan.t
(@joantabb)
Veteran Member Moderator

Hi Jon. 

I don't recall you saying it was prebuilt, so let's take a massive leap of faith and suggest that you didn't get a printer built by the apprentice on his first day...

I would hope that the delivery company didn't treat it like a football on the way to you... so I would start off by oiling the smooth rods with a little light oil, machine oil, or sewing machine oil, perhaps gun oil if you have it. and moving the axis backwards and forwards, or left to right a number of times  by hand, and hopefully you will feel a difference and hear and improvement. then try printing again... 
Prusa say the bearings are pre lubed, other folk say that they are treated with a rust preventative which must be washed out and replaced with Grease...  I don't know one way or the other.

My  latest kit came with a tube of white lithium grease and I greased the bearings on assembly even though the assembly guide didn't tell me to do so... 

if you received a tube of grease with your prebuilt kit, it might be an idea to use that as recommended in the Prusa maintenance guide. immediately. https://help.prusa3d.com/en/article/i3-printers-regular-maintenance_2072#rods-and-bearings

I hope this helps, 
regards Joan

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 : 26/03/2020 3:27 am
jon calma.v
(@jon-calma-v)
Active Member

@joantabb

Thanks Joan,  I thought you realized that its pre-built based on my topic.  In any case, after your first reply, I moved the x and y axis around and narrowed down the issue to the y axis --  there is a resistance from time to time on the bed when I move it back and forth. I haven't applied any lubrication yet but after a few back and forth movements I did, the resistance was almost non-existent.  Now however, I am printing a model and I can here some metal noise, like something loose... trying to observe it, seems like its coming from the y and z axis assembly -- when ever the it moves on either directions (y or z) there is some "loose parts" noise.... I am trying to compare it now with my 1 yrs old mk3s, and I can confirm something's amiss with the new one.  

I will do the lubrication as per the link you sent, but any other advise or assistance you can share is greatly appreciated.

thanks!

jon

Posted : 26/03/2020 6:46 am
1agkirk2
(@1agkirk2)
Active Member

@jon-calma-v

I had a similar problem wrt stiffness in the axis movement in one direction.  Unit worked fine for a few prints but then would not Home correctly and started failing Calibration attempts.  I oiled the steel rods carefully and I no longer have any problems.  My guess is Prusa got a batch of linear bearings that had not been properly oiled.

Posted : 26/03/2020 10:37 pm
joan.t
(@joantabb)
Veteran Member Moderator

Sorry Jon, 
I was looking at posts that needed approval, and I was looking for embedded spam etc. I didn't check the section title. 

Totally My mistake. 

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 : 26/03/2020 10:57 pm
jon calma.v
(@jon-calma-v)
Active Member

@1agkirk2

thanks for that advise, will try it and hopefully everything will be good.

regards,

jon

Posted : 27/03/2020 3:13 pm
jon calma.v
(@jon-calma-v)
Active Member

@joantabb

no need to apologize, no harm done. just wanna see how to resolve my issue. I will try lubing the moving parts as at all axis, hopefully that solves my issues.

thanks!

jon

Posted : 27/03/2020 3:15 pm
Robert-mm200
(@robert-rmm200)
Noble Member

Seriously though - treat light oil as a diagnostic technique - not a long term solution. It can get you going and through a few prints. Proper lubrication with an appropriate grease is the way to go long term.

Posted : 27/03/2020 3:58 pm
jon calma.v
(@jon-calma-v)
Active Member

@robert-rmm200

thanks for the tip!!! will keep that in mind... 

i appreciate all the advise you are giving me, i know nuts about all these.

thanks,

jon

Posted : 27/03/2020 4:09 pm
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