[Solved] Prusa Mini: Filament frequently jams after about 2 hours of printing  

RE: Prusa Mini: Filament frequently jams after about 2 hours of printing

Just another data point: I adjusted the gap about 6 weeks ago and I haven't had the problem again.

RE: Prusa Mini: Filament frequently jams after about 2 hours of printing

@mike_mike

Yes! I did the same thing and the printer has been printing beautifully ever since.  Once you have this dialed in, the print quality is really remarkable.  Only a 2mm gap and you are good to go.

RE: Prusa Mini: Filament frequently jams after about 2 hours of printing

Same issues for me as all , after a few weeks of great prints , I have ended up with frequent jams after a few good layers. I rebuilt the hot end several times and ensured the PTFE tube didn't have a gap. I have not tried to 235 temp yet, I am hoping this might solve my problems. Is there a way to make that temp default for PLA ? Has anyone that raised the temps experienced the problems again ?

RE: Prusa Mini: Filament frequently jams after about 2 hours of printing

I've had consistently good printing with a wide variety of PLA filaments at 225°C on my two MINIs (after fixing the PTFE tube gap).  I created config files with the elevated temperatures for PLA and my go-to PETG.  Maybe someone knows how to change the default temperatures (I don't).

RE: Prusa Mini: Filament frequently jams after about 2 hours of printing

After fixing the gap, it's been working great for me for weeks at the default 215° with a few different brands of PLA.

RE: Prusa Mini: Filament frequently jams after about 2 hours of printing

So my first print after setting the temp to 230, sucessfull! so far so good. Could this be an issue with the thermistor  ? It worked fine for many weeks and lots of long prints. IS there a way to change the temp for the z calibration to 230 ? I have trouble with calibration as well at 215. 

RE: Prusa Mini: Filament frequently jams after about 2 hours of printing

I wonder if I have heat creep issues ? I put thermal grease on the heat break after reassambly ( dow Corning 340 but still facing the same issues . I am doing another print at 215 and its a small one (15mins) and no issues with the print. I did a couple cold pulls and no clog was there. Something is blocking extrusion and I don't know what it is, doesnt seem to be temp or a clog. Thoughts ?

RE: Prusa Mini: Filament frequently jams after about 2 hours of printing

@kevman

I had a couple issues where the bowden tube was too tight at the crimp rings.   You might want to check that.

RE: Prusa Mini: Filament frequently jams after about 2 hours of printing

@kevman

Hello

I faced issue reported by Frankincell: at crimp rings level (both) of bowden PTFE tube, diameter was significantly smaller: this tube fully disassemble from the printer, I can feel some resistance on a filament I tried to insert by hand at both ends.

I solved this by drilling those areas with 2mm diameter tool using my Dremel. no more "brake feeeling" by inserting again a filament by hand after this.

RE: Prusa Mini: Filament frequently jams after about 2 hours of printing

My tube was a bit tight at the crimps, so I just ran a drill down the tube to restore its diameter at the tight points.. The only problem is that at 1.75mm you need an uncommon drill size, but luckily I have a set which go from 1mm to 6mm in 0.1mm increments.. So I just found one that did the job.

RE: Prusa Mini: Filament frequently jams after about 2 hours of printing

Thanks for the responses. I have checked the crimps they are good, the filament glides nicely. I went had to rebuild the hot end again as it jammed once more. I had the heater block gap at 2.2mm  after compressing the ptfe tube as per the instructions and support suggested bring it to reccemended value of 4.8 which I did, but that causes the hot end to jam up as well. So I have it at about 3 and I am at a loss. I was getting great prints for weeks and I can't seem to chase this problem down. Yesteray the print I mentioned were sucessfull all eventually failed with clickign and under extrusion and ultimately jamming. Almost every possible troubleshooting scenario is not working for me.  What do I do ?

RE: Prusa Mini: Filament frequently jams after about 2 hours of printing

@kevman

Hello, sorry to ask you this, but did you check all points mentioned by Prusa (for this specific issue), as well as various photos I posted on April 14th into  this post (page 4 now) regarding this issue?

Did you try to raise extrusion temperature as well (+5 and +10 °C)

Did you check extruder main gear teeth to make sure interleaves are not full of plastics résidus ?

I removed the plastic part covering it, so I can easily engage any filament , rolling this gear by hand,  up to see it at extruder output...and to clean this gear teeth for filament with some air pressure at end of each prints.

If all was already tested , then I guess you need to claim Prusa for a recall and repair under warranty.

I don't know all European regulations across all countries, but this issue in France is considered as "hidden vice", made by wrong design , which induce owners not able to use it properly….and Prusa would be fined for this, easily...

This was also detected and reported quiet a bit early by some well-known Youtubers while testing the Mini...

It is not contributing to Prusa reputation, so I do not understand why clear announcement and real efficient correction kit is not already sent to all facing this clogging/extrusion issue...

RE: Prusa Mini: Filament frequently jams after about 2 hours of printing

Posted by: @sylvain-t2

@kevman

Hello, sorry to ask you this, but did you check all points mentioned by Prusa (for this specific issue), as well as various photos I posted on April 14th into  this post (page 4 now) regarding this issue?

Did you try to raise extrusion temperature as well (+5 and +10 °C)

Did you check extruder main gear teeth to make sure interleaves are not full of plastics résidus ?

I removed the plastic part covering it, so I can easily engage any filament , rolling this gear by hand,  up to see it at extruder output...and to clean this gear teeth for filament with some air pressure at end of each prints.

If all was already tested , then I guess you need to claim Prusa for a recall and repair under warranty.

I don't know all European regulations across all countries, but this issue in France is considered as "hidden vice", made by wrong design , which induce owners not able to use it properly….and Prusa would be fined for this, easily...

This was also detected and reported quiet a bit early by some well-known Youtubers while testing the Mini...

It is not contributing to Prusa reputation, so I do not understand why clear announcement and real efficient correction kit is not already sent to all facing this clogging/extrusion issue...

 

Thank you for your response 

To answer your questions

1. Yes I followed the entire guide in detail , did the hot end adjustment for the PTFE tube several times. 

2. I did try raising temperatures , I eventually tested all the way up to 230C it seemed to be working , but that failed after about 45 minutes same issue. 

3. I've been rather obsessed with cleaning the extruders gears, I take an exacto knive and scrape out each tooth and then blow out with compressed air. Very tedious but I wanted to make sure I was on top of that issue. 

I've been in touch with Prusa support , but I have to reach back out today since the latest attempt has failed. I want to have faith that they will find a fix for this and that I'm not experiencing this alone. I have ordered new parts , heater block, heat break and nozzle to see if any of this would help. I am doubtful. 

RE: Prusa Mini: Filament frequently jams after about 2 hours of printing

I am confuse, isn't this topic solved? 

RE: Prusa Mini: Filament frequently jams after about 2 hours of printing

@atomleef

I'm also confused, the topic was solved some time ago.  It's the topic that never dies.

RE: Prusa Mini: Filament frequently jams after about 2 hours of printing

sorry you are all confused, but I have the same symptoms and the answer in this post didn't solve my issues. I have upgraded to a bondtech heatbreak and still have the same issues. I was looking for some ideas on what to do next.  I think there is perpetual heat creep in my hotend and it cannot be resolved with any of the answers or solutions I have seen so far.

RE: Prusa Mini: Filament frequently jams after about 2 hours of printing

I have a NIST-calibrated Fluke62 infrared thermometer on order that I'm purchasing for another project, but I will definitely use it to check out hot-end temperatures on my different printers.   I'm very curious to know how temperatures differ between the MK3S and the MINI.  After experiencing the same problems with the MINI as everyone else, I slid the hot-ends upward as high as they will go.  My two MINIs are now printing all PLA brands reliably at 215°C , though I have been doing the first layer at 225°C.

RE: Prusa Mini: Filament frequently jams after about 2 hours of printing

@kevman

Hello,

If all actions you made did not solve your issues, then you should initiate a return to Prusa for warranty coverage.

Thanks to the hundreds of Mini owners having faced such extruder issue, (and still…)  they can not refuse...I guess..

Best regards

RE: Prusa Mini: Filament frequently jams after about 2 hours of printing

@kevman How prusa answer? Can you share prusa 's answer? thank you

RE: Prusa Mini: Filament frequently jams after about 2 hours of printing

I have been having issues with extruder skipping and awful extrusion lately after hours and hours of printing.  I still have in consistent first layers which is another topic.  I pulled the stock ptfe tube out today after reading through the posts and compared it to the one from spare kit.  Is it normal for it to me a few mm shorter due to compression?  Look at the difference in this not so scientific taken photo. I just swapped them out and will try a test print.