7 cold pulls and still not getting great results
My printer was running well but I didn't use it for around two weeks and I'm now having issues -
I mistakenly left it powered on (although unheated) - it's also in an enclosure so I'm not sure why these problems have started.
Nonetheless, I ran a 20 minute print to test it and although the shape was good, there were structural issues (i.e. a lot of gaps in the layers), and when I tried to run a test print to check for issues hardly any filament came out at all. I also couldn't unload the filament, so it seemed like the nozzle was clogged.
I followed the guide on the Prusa website, by:
• Removing the bowden tube from the extruder
• Heating the nozzle to 270 C
• Inserting filament directly into the extruder
• Setting the printer to 'Cool Down'
• Pushing filament through the extruder until it stopped melting at 160~ C
• Waiting until 90 C then pulling the filament gently upwards with pliers
I did this 7 times and here are the results (from left to right):
It's clear there's an issue but it's concerning that it's not getting any better. I'm hoping I've done something wrong and it's not a major issue with the printer - any advice would be massively appreciated please! 😥
It felt really promising pushing the filament in and seeing it flow out the nozzle (although it did curl up a bit at times), but the filament strands from the cold pulls don't look very good or clean.
I also noticed the clog has caused a build up of 'filament dust' in the extruder gears from where the printer has tried to retract the filament (which ended up just grinding it up as it was stuck) so I'll need to dismantle that and give it a good clean too. Thankfully the guide on the website is really good. 😀
RE: 7 cold pulls and still not getting great results
Maybe replace ptfe tube and do selftest
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RE: 7 cold pulls and still not getting great results
Maybe replace ptfe tube and do selftest
Exactly this. I have bought several extra PTFE tubes and when this kind of things happens, I replace. What filament do you use? Extensive use of high temperature filament can cause this. I have had to replace the PTFE tube after using extensively for PC blend and TPU. I just consider the PTFE tube a wear item. Possibly, also adjust the heatbreak as Prusa specifies. It makes a difference in how much heat gets to the PTFE tube.
Regards,
Mark
RE: 7 cold pulls and still not getting great results
I can look into a bowden tube replacement - do you have any recommendations for brands please? I bought my printer second hand and didn't get any spares
Also I only ever print PLA+, at 215 C for the first layer and 210 C for other layers
RE: 7 cold pulls and still not getting great results
Is it definitely a bowden tube issue ? As I was getting these cold pull defects by inserting filament directly into the extruder (not through a tube)
RE: 7 cold pulls and still not getting great results
Is it definitely a bowden tube issue ? As I was getting these cold pull defects by inserting filament directly into the extruder (not through a tube)
You could try replacing that but not what I meant I thought you were on mk4 anyway incisive the extruder there should be small ptfe tube try replacing that
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RE: 7 cold pulls and still not getting great results
https://help.prusa3d.com/guide/how-to-replace-a-hotend-ptfe-tube-mini-mini_119449
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RE: 7 cold pulls and still not getting great results
Yes, the hot end tube is what I meant. There are some replacement hot ends but from reading here none are universally better in every situation. So, I just replace the tube once in a while when needed.
Regards,
Mark
RE: 7 cold pulls and still not getting great results
Thanks all, just ordered some and will give it a try when they arrive 🙂
RE: 7 cold pulls and still not getting great results
Yes, the hot end tube is what I meant. There are some replacement hot ends but from reading here none are universally better in every situation. So, I just replace the tube once in a while when needed.
Regards,
Mark
Yeah after about 1000 hrs
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RE: 7 cold pulls and still not getting great results
Or when you get symptoms of it been deformed or jamed
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