Filament gets stuck in extruder Prusa Mini+  

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Craftop
(@craftop)
New Member

Good day all,

Since a week, I own the Prusa Mini +, about which I am very happy! Out of the box, the printer performed great. However, since yesterday I experience some problems. It happened to me twice that, during a print, the filament (both times PETG) got stuck in the extruder, resulting in a printer that tries to continue its print, however no filament comes out of the nozzle. At first, you don't notice anything, after some time the printer starts to squeek (after which I stopped the print). I thought the nozzle or hotend was clogged. However, after taking apart the extruder, I saw that the extruder flattened a small part of the filament, which resulted in a wider part hence the filament wasn't able to enter the PTFE tube toward the hotend. At first, I thought I tightened the bolt (with the spring) too fast, but today it happened again and now I start to wonder if that really was the case, the bolthead was flush (or even stuck out a little) with the surface (as described by Prusa), so I. Is it possible the extruder motor becomes too hot during printing, slightly warming and softening the filament? Or should I keep on playing with this bolt? Sadly, I did not make any picture to show what it looked like.

I hope someone can help me to fix this issue! Thanks in advance!

Posted : 16/12/2020 11:12 pm
Simon B
(@simon-b-2)
New Member

I am in the same situation but with PLA... I am interested in the responses... 🤨 🤨 

Posted : 16/12/2020 11:33 pm
BitScout
(@bitscout)
New Member

I'm having the same problem with one single filament (Amolen glow in the dark PLA). The extruder basically grinds a piece out of the filament, and then starts making a loud clacking noise, which made me notice nothing was being extruded any more. This happens after maybe 10 minutes or so, maybe 20.

Posted : 19/12/2020 10:03 pm
shodaiultraman
(@shodaiultraman)
New Member

My filament is stuck in the extruder as well, it doesn't come out either 🙃 

Could someone point me to a guide on how to open the extruder, please?

Posted : 21/12/2020 3:52 pm
Craftop
(@craftop)
New Member

@shodaiultraman

For that, take a look at https://help.prusa3d.com/en/guide/how-to-access-and-clean-the-extruder-pulley-mini_126457/

 

Posted : 21/12/2020 3:57 pm
Jonas
(@jonas-5)
New Member

It sounds like you might be experiening a more or less common issue with the mini. You can find many topics discussing this and related issues on the forum (for example here: https://forum.prusaprinters.org/forum/assembly-and-first-prints-troubleshooting/underextrusion-4/ ) . Search for underextrusion or clicking. In my particular case what helped was to reposition the hotend (see step 21-23 in this article: https://www.help.prusa3d.com/en/guide/how-to-change-a-heaterblock-heatbreak-mini_122769 ). Mine was too low and the PTFE-tube inside the hotend was not corretly compressed. The molten filament was not pushed correctly through the nozzle and created a blob. This increased the resistance to the point that the extruder gears ground down the filament when trying to push it through. 

This was the solution in my case, no guarantee it will work for you. By the way, Prusa's support is very good, you could start with contacting their chat. 

Hope this helps 🙂

Posted : 21/12/2020 6:03 pm
toz, Craftop and BitScout liked
shodaiultraman
(@shodaiultraman)
New Member

(Not sure if this was aimed at my post or OP's, but) thank you!

Posted : 21/12/2020 9:33 pm
Jonas
(@jonas-5)
New Member

@shodaiultraman

I wasn't sure, either 😀 I guess it was more like a general contribution to the conversation than a reply to one defined post 😝 

 

Posted : 22/12/2020 8:20 am
BitScout
(@bitscout)
New Member

An observation: One single mask anti fog clip printed fine, but three next to each other caused the problem somewhere in the middle.

My hypothesis (as a <1 month user) is:

- A nose clip has roughly three parts per layer: left clip, center part, right clip

- By printing three at a time, the filament has to be pushed back and forth very quickly.

- Stroke length varies throughout the model.

- At one "perfect" ("resonant") layer height, there's more back-and-forth than actual extruding, and maybe the end of the filament retraction even happens exactly when it is supposed to be pushed again, doubling the desired speed & direction change.

Posted : 22/12/2020 8:34 am
Craftop
(@craftop)
New Member
Posted by: @jonas-5

It sounds like you might be experiening a more or less common issue with the mini. You can find many topics discussing this and related issues on the forum (for example here: https://forum.prusaprinters.org/forum/assembly-and-first-prints-troubleshooting/underextrusion-4/ ) . Search for underextrusion or clicking. In my particular case what helped was to reposition the hotend (see step 21-23 in this article: https://www.help.prusa3d.com/en/guide/how-to-change-a-heaterblock-heatbreak-mini_122769 ). Mine was too low and the PTFE-tube inside the hotend was not corretly compressed. The molten filament was not pushed correctly through the nozzle and created a blob. This increased the resistance to the point that the extruder gears ground down the filament when trying to push it through. 

This was the solution in my case, no guarantee it will work for you. By the way, Prusa's support is very good, you could start with contacting their chat. 

Hope this helps 🙂

I recently took out the PTFE tube from the hotend, measured it (since I read it might be too short, but it was ok), and placed it back into the hotend and attached to PTFE tube that supplies the filament to the nozzle. After that, I loosened the three small screws in the nozzle and pushed the nozzle up to compress the PTFE tube. After fixing the three screws again, the nozzle was back together. Until now, this indeed solved the problem for me. Both  PLA and PTFE print fine! I advise everyone experiencing this problem to start with this. It is a fairly easy and fast thing to do!

Posted : 22/12/2020 5:54 pm
JoanTabb
(@joantabb)
Moderator

Consider changing the grub screws for socket screws for ease of future maintenance

 

A number of users have split the sockets on the grub screws

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 : 22/12/2020 8:21 pm
Valady Nagarajan
(@valady-nagarajan)
Active Member

Could you please advise on the size of screws that can replace these three small grub screws - Diameter, thread size and length will be helpful. Thanks

Posted : 01/01/2021 4:30 pm
JoanTabb
(@joantabb)
Moderator

they would be M3 (Metric 3mm Screw thread) I don't have a mini, so I can't advise on length. if you take one out, then put a needle or cocktail stick in the hole, you can  measure the depth of insertion and then get a screw about that long, I am guessing 10mm
common lengths are 6mm, 10mm and 12mm. I bought a selection of M3 Stainless steel cap screws off ebay I also bough some thin Hex nuts, thin Square nuts and washers, plus some brass inserts, and I use them on the printer and on models

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 : 01/01/2021 4:53 pm
Valady Nagarajan
(@valady-nagarajan)
Active Member

Thanks for your prompt reply. I will check the screws the next time I will be required to adjust them. Right now the printing is going on smoothly. 

Posted : 01/01/2021 5:25 pm
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