Prusa Mini: stops extruding, starts clicking  

RE: Prusa Mini: stops extruding, starts clicking

Look here - https://forum.prusa3d.com/forum/assembly-and-first-prints-troubleshooting/underextrusion-4/

RE: Prusa Mini: stops extruding, starts clicking

Just got bit by this. A second time. After a month after getting brand new hot end because I broke the first one previously. Clicking, whirring, no extrusion...

Tried manual purge (unscrew bowden tube, heat it and push the filament in by hand), everything seemed fine, means not a clogged nozzle.

Next I tried cleaning the feeder. Clean the cogs by needle, blowed with compressed air, try to mess with the spring loaded screw, still not fixed, so it's not feeder.

Ok, so hot end, my nemesis from last time... the distance between block and heatsink is around 4mm, so no problem here. Tried a couple of cold pulls, looked clean and didn't fix anything. So, unscrewed the fitting and replaced the PTFE tube. During removal of possible debris from the hot end. I pulled out what seemed like a shaving of PTFE tube. Not sure when and how it got there. Anyway, after replacing the PTFE tube and reseating the heater block, it prints again. The bad PTFE tube still had the proper length of 43,something +- 0,1 mm. the one from my first attempt was, indeed, almost a milimeter shorter.

Anyway, I begin to think the compressed PTFE tube is a design flaw of this printer. I suspect it gets used to the compression and stops being perfectly sealed after some time, and that's what's causing the trouble. I wonder what can be done with it...

RE: Prusa Mini: stops extruding, starts clicking

Same here, I moved up the the heat break, but got jams again a week later. I replaced the PTFE with the spare, the one off the printer was 1 mm shorter than spec. I also suspect the PTFE can get compressed over time.

I wonder if a stainless steel insert could replace the PTFE tube? Or, a new design of heatbreak.

RE: Prusa Mini: stops extruding, starts clicking

I've got the same problem with other filaments than prusament. I've tried two different makes of PLA (One was Primacreator Easyprint). As soon as I use those, the extrusion stops after the first layer. It seems to under extrude so I tried raising the temp (didn't work), I increased the extrusion factor to 1.05 (didn't work). But as soon as I go back to the Prusament I have everything is fine!

RE: Prusa Mini: stops extruding, starts clicking

We are not the only ones to meet this design problem ... Bondtech solved it, I changed the heatbreak (and the extruder) by this and no more problem!

RE: Prusa Mini: stops extruding, starts clicking

@serge-d

I've just done the same upgrades, seems to work well

RE: Prusa Mini: stops extruding, starts clicking

Posted by: @patrik

I've got the same problem with other filaments than prusament. I've tried two different makes of PLA (One was Primacreator Easyprint). As soon as I use those, the extrusion stops after the first layer. It seems to under extrude so I tried raising the temp (didn't work), I increased the extrusion factor to 1.05 (didn't work). But as soon as I go back to the Prusament I have everything is fine!

RE: Prusa Mini: stops extruding, starts clicking

Have you tried cleaning filament?

RE: Prusa Mini: stops extruding, starts clicking

I've tried cleaning the filament, extruder and the nozzle. I managed to print Add:north E-PLA using the Prus PLA profile and setting the first layer temp to 220, other to 215 and increasing the extrusion multiplier to 1.08. It prints but it is still underextruding!

RE: Prusa Mini: stops extruding, starts clicking

Yep, I noticed this problem too.  I have already done the PFTE tube replacement and things were fine for a while. Sometimes I fix it by unloading and loading the filament which I think means it's not a nozzle problem.  Sometimes I just leave the printer off for a while and that will work.

I'm thinking it's 4.0.5 since I'm also getting screen freezing during a purge at 99%, pausing and then stopping a print and unloading a filament.  Since I typical see this when the extruder problem occurs, there may be a connection.

RE: Prusa Mini: stops extruding, starts clicking

I've got it working! I noticed that the heat breaker was sticking out of the fan a bit to much. Pushed it in 5 mm and now I can print the troublesome PLAs that didn't work before. Add:North E-PLA worked with Prusa PLA profile and for an unbranded PLA I had to increase the extrusion multiplier to 1.08 and increase the temp by 5 degrees for first and other layers.

And the PTFE tube was a bit short ~0.3-0.4 mm. The replacement I got was the right length but it didn't have the chamfer at the ends so I couldn't use that.

RE: Prusa Mini: stops extruding, starts clicking

I've upgraded to the Bondtech heatbreak and haven't had any problem with any of my filaments since.

RE: Prusa Mini: stops extruding, starts clicking

Any good STL file for a jog to cut and shape the PTFE tube, I'm really after something to shape that end.

RE: Prusa Mini: stops extruding, starts clicking

Posted by: @raymate

Any good STL file for a jog to cut and shape the PTFE tube, I'm really after something to shape that end.

This is what I have used.
ptfe-tube-chamfer-and-cut-jig

RE: Prusa Mini: stops extruding, starts clicking

@steve-smith

I use that one and one by Karl:  

https://www.prusaprinters.org/prints/34035-ptfe-multitool

RE: Prusa Mini: stops extruding, starts clicking

@cwbullet
Wow hadn't seen that one before.. I will have to check it out.

RE: Prusa Mini: stops extruding, starts clicking

Thanks @cwbullet and @steve-smith printing both 😀 

RE: Prusa Mini: stops extruding, starts clicking

1. The problem I’m having is when I load the filament in and try to print it grinds up the filament and stops printing. I can’t even get a first layer down without it grinding up. I already tried cleaning the extruder, raising the heat block, and replacing the nozzle and nothing worked.

RE: Prusa Mini: stops extruding, starts clicking

@hu3e

Have you tried cranking up the heat a bit?  I have a Mini+ that has the problem you describe but at 230C (PLA) it prints beautifully.  Also make sure the extruder tension is not too tight: with filament loaded, head of screw is roughly flush with the housing.