[Solved] Strange noise - where to start?  

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Ted
 Ted
(@ted)
Active Member

Hello All!

I have a noise problem on an i3MK3S - when the bed is moving in the Y-axis, there is a sort of a rattling noise, also when the bed changes direction in Y and I think that the 1st Layer is continuosly loosing its precision...

When I apply a soft pressure on the front or back end (right side of the bed, see video) the noise goes away!

My question is: 'Where to start with repairs?!'

This is the first problem I have had in a year (considering myself lucky and having a very good printer) - I have included a short video where I am printing a first layer test, just boost up your speakers and you might hear what I mean!

Thak you all for your help!

Best, Eduard[video width="1920" height="1080" mp4="https://forum.prusaprinters.org/wp-content/uploads/2021/05/i3MK3S.mp4"][/video]

https://forum.prusaprinters.org/wp-content/uploads/2021/05/i3MK3S.mp4

This topic was modified 1 month ago by JoanTabb
Posted : 10/05/2021 3:40 pm
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 --
(@)
Illustrious Member

Dry bearings make noise. What grease did you use to pack the bearings before installation?

Also - some of the components on the bed seem rattle prone - the shims under the heater for example, even the print sheet against the screw stops -- lol -- I have to make sure the print sheet is fully pressed against the stop screws or else I get a rattle. Steppers shake everything in the vicinity - so a stable surface under the printer can also help.

This post was modified 1 month ago by --
Posted : 10/05/2021 6:07 pm
Ted
 Ted
(@ted)
Active Member

Thanks Tim,

the printer was no kit, it came completely assembled from the factory. 

When I perform the regular maintenance accordimg to the suggestions on the knowledge base I use the grease supplied by  Prusa.

I have a suspicion that the one or more of the u-bolts which hold the bearings has\have come loose and causes the problems. I now will check all the nuts and bolts of the bed and search for loose ones...

Eduard 

Posted : 10/05/2021 6:32 pm
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 --
(@)
Illustrious Member

@ted

Just make sure the u-bolts aren't over-tightened, they can deform the bearings and cause seizing.  And all you should need to do for the shims is run through the screws on the top of the heater circuit board. No disassembly needed. About the only other place you'll get rattles is the connector shell at the back of the bed, a couple of screws there. 

The rattle from the steel sheet barely touching the two stop screws is also difficult to diagnose. It sounds like it is coming from everywhere.

The rattle from loose bearings, the bearings themselves rattling on the rod, is actually pretty normal. Grease helps. Prusa abhors greasing the bearings and installs them dry. To eliminate that rattle you have to do a full disassembly and pack the bearings when off the printer. Grease on the rods may help, but a few drops of light machine oil will more likely get inside the grease seals and quiet things down.

ps: 3D printers are not quiet ... lol.

Posted : 10/05/2021 11:01 pm
Ted
 Ted
(@ted)
Active Member

@tim-2

Thanks again - will take your advise.

To the 'ps' - I know - (and there is a big difference between the noise of the MK3S and the MINI, I have them standing side by side), but the MK3S was quiet and now there is this noise, so somethings got to be wrong.... - and there is this indifferent first layer thing, which is also new...

Eduard

Posted : 10/05/2021 11:42 pm
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