First major filament jam that I can't fix with the normal methods
I've had my Prusa MK3S for almost two years now and it's been printed amazingly well with almost no maintenance (just oiling the bearings and shafts) and very few jams that I couldn't fix myself. Unfortunately, last night, I didn't catch the printer before it used up the rest of a spool of PLA. I heard the "out of filament" beep but when I tried to extract what was remaining, nothing came out. I tried loading the new filament but while it engaged with the gear, it got stuck immediately and would not advance at all. Eventually, after fighting with it for a while, I had to cancel the print and then I went through the process of trying to clear the jam.
1) I increased the head temperature to an ABS setting and let it sit for a while. After a while, I noticed that some filament gooped out the extruder. I then tried reloading the filament, but it made no more progress than it had before.
2) I have some acupuncture needles and I gently tried to insert one into the filament entry point at the top of the head. While the head was hot, I could feel the needle push through the filament. Unfortunately even after trying this multiple times and then trying to load new filament, I was completely unsuccessful.
3) I tried letting the printer cool down and heat up again and tried steps (1) and (2) but was also unsuccessful.
I opened up the side hatch on the head to see if there was something obvious blocking the white PTFE tube. The PTFE tube seems to be completely blocked with the broken strand of filament that didn't make it out of the head.
So, what are my options? I'm wondering if I should heat the head up again and this time try to push the filament down with the short part of an allen wrench? I don't want to damage something, but I also would like to avoid having to replace the PTFE tube and maybe other parts if I can avoid it. Any advice?
RE: First major filament jam that I can't fix with the normal methods
It's not the most clear picture, but the PTFE tube seems to be totally blocked.
RE: First major filament jam that I can't fix with the normal methods
Good news!!! After re-reading the manual this morning, I saw the bit about using the acupuncture needles to push the filament out from the tip of the extruder. I tried that and I was able to push the blockage out!!!
Now, however, the extruder makes a pretty loud grinding noise when it loads the filament. I'm wondering if the idle gear is not turning very smoothly. I did notice that when I opened the side door, that it was not turning smoothly in my hand. Both loading and unloading the filament produce a pretty awful screetching noise. The printer printed the first layer of the PRUSA badge just fine so that seems to be working and when printing that filament, it generally sounded okay except when it changed directions (maybe reversing directions?)
Maybe I do need to get a new idle gear, shaft, or side-door for the extruder head.
RE: First major filament jam that I can't fix with the normal methods
Ah! Found the source of the noise. The bearings inside the idler gear were REALLY dirty. The idler gear was barely turning at all! It was sticking really badly. I'm going to clean and grease it.
RE: First major filament jam that I can't fix with the normal methods
Please ensure that the Idler shaft is supported on both ends, sometimes one end slips out of it's support
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
RE: First major filament jam that I can't fix with the normal methods
Yes, I did see that when I first tried to open the access panel. The shaft had pushed through so that i had to pull out the bolt "hinge" to get the panel off.