[Solved] Crackling sound during first purge  

New Member


Not sure how to explain this behavior but since a few days now every time we try to print something on our MK3/MMU2s the filament has a hard time to load before and during the first purge. Sometimes it takes 2 to 3 tries to have the filament taken by the extruder and sometimes it fails completely.

The current filament we are using was working fine last week and we got some decent print with it.
We tried with an old filament () that might have gone bad because we cannot load it at all (it's probably more than 1 year old and wasn't stashed in perfect condition)

We also tried different brand of filament and it's the same issue :


During the loading of the filament, before the print start to do the first purge, the gear inside the extruder makes some crackling noise as if they are not able to get a grip on the filament and that cause the load issue. I tried to screw the spring screw more and it kinda works but the purge still gives me some crappy dotted lines.

We disassembled the whole extruder, replaced the tube, cleaned the whole thing but the problem persist.

I want to add that as soon as the purge is done this crackling sound disappear, the first layer is printing ok (for now).

I'm wondering if someone could give me some advice on what to check / change so I don't damage the extruder gear (what I fear the most).



Posted : 16/01/2020 7:12 am
New Member

Update: After the current print (large flat piece) and 3 layer here is the result.. As You can see the result is super bad 🙁

[caption id="attachment_10273" align="alignnone" width="600"] crappy layer[/caption]

Posted : 16/01/2020 9:39 am
Noble Member

sounds like too much friction in the buffers/feed system. You must be able to pull filament through with relatively little resistance, else you'll get this exact problem.

Posted : 16/01/2020 2:11 pm
New Member

Actually I found out the screw was not tightened enough as per the upgrade manual.


I did that and not the clicking sound is gone but I now get some issues with the ir sensor going from 1 to 0 during the print. I would say it happens mostly when there is a lot of retraction. I will close this topic and check for this issue.



Posted : 17/01/2020 9:46 am

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