Prusa mk3s clicking

My mk3s starts to click almost every print and stops extruding.
Does anyone know how to fix this problem?

That sounds like a jam The extruder gear will skip by times.

Try to bring it up to temp and in the menu release the stepper and see if you can push filament through by hand.


I’ve had one Customer bring in his MK3 and when I opened the Access door to the Dual Bondtech gears. I Seen that the Grub/set screw for the Driven one was loose and hitting the outer gear and binding. Customer stated One print earlier machine was fine, and was great for years. He asked me how this happened all a sudden. All I could do is: /Shrug it’s a machine these things happen!

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@Keith LOL I actually know why that happens! Not so much with printers but my work we have a few hundred gears held with grub screws. When tight the vibrations that cause them to move have very little effect. Once the pressure reduces enough they are able to move quite a lot. The second it stops applying pressure it moves far more, So what seems tight one moment is very loose the next.

The OP could be a loose grub screw too. My experience is it clicks with a nozzle jam. It could be many other of things, a jam seems to be the most likely.

You haven’t provided much information here. What type and brand of filament are you using, what temperature is the hot end at, what size nozzle are you using? Does it do the purge line at the beginning of the print and how does it look. How far into the print before it clogs. I.e. does it make it past the first layer? Have you opened the idler side door to inspect the bondtech gears. There may be ground up filament present that needs cleaning. How much have you adjusted tension screw with the spring that attaches to the idler?

Ive used multiple types of filament, mostly sakata, but ive cleaned out the extruder lastnight with a brass brush and compressed air can. Did 3 cold pulls, incresed temp to 220 and tightened the grub screw more than i usually would. So far smooth sailing, over night print was successful and its printing beautifully as of now. Thanks for all your help guys!

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The only more general thing I might add is when you trim the filament do so at at least a 45º angle if it is too flat on occasion it binds at the opening of the throat. I suspect this was not your issue but I think it is good practice, the tolerances are quite tight with the Prusa.

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