Filament Leakage - MK3S+
Hello guys,
I'm new to 3D printing world, that's why I ask for your help.
Recently I received THERMAL ANOMALY error. I took a closer look and I observed that my nozzle and heatblock were full of filament. The filament was leaking just before entering the heatblock, and just before entering the nozzle. Also, I observed that there was also black filament, which was strange because I haven't printed with black filament(Prusa Galaxy Black PLA)recently. I thought that maybe a piece from the extruder might be melting, but I didn't find anything. I disassembled the whole extruder and watched for any broken parts, there wasn't any and I didn't find any piece that might be melting either. So, I cleaned the parts and tried again with same result. I bought a brand new heatblock, PTFE tube( I thought it was guilty - I was wrong) and replaced the nozzle with a new one. While I assembled the hotend I realized that the nozzle and the heatbreak weren't tighten how they should. I had big hopes that this was the whole problem, so I assembled everything back and ran again trough the whole calibration cycle again. It worked fine until yesterday. Again, the same problem as before although now the pieces were brand new. I was printing with Prusa Orange PETG, but again there was black filament. Where does that black filament come form? It might be the orange filament but burnt down? Or a piece might be melting? How can I solve this problem?
Thanks in advance 🙂
Check you are using genuine E3D nozzle - there are known to be clones available that are a fraction short in the thread.
Then pay particular attention to the diagrams at the bottom of this page:
https://help.prusa3d.com/en/article/changing-or-replacing-the-nozzle-mk2-5s-mk3s-mk3s_2069
Cheerio,
RE: Filament Leakage - MK3S+
Hey Diem,
Thanks for your reply!
I bought all the parts from Prusa so I guess I should be good with that.
I carefully walked trough all the steps from that article and checked multiple times if I assembled it according to the diagram. Also, I don't think this might be the problem because it worked just fine before it happened again. 🙂
You have to get the nozzle and the heater block into close contact or you will have leakage. A scratched surface can also leak. It can take a week to ooze through.
Cheerio,
RE: Filament Leakage - MK3S+
The sealing surfaces of nozzle and heatbreak are those that face each other as shown in prusa's page @diem posted a link of. As he suggested, it seems ok according to the image you sent to move the nozzle a little further in. But at least a tiny gap between nozzle and heaterblock is necessary. Otherwise the sealing surfaces are not tightened against each other. They have to be pristine prior assembly. If available, using a torque-wrench is preferable.
RE: Filament Leakage - MK3S+
That was the problem first time, the nozzle and the heatbreak weren't in close contact with each other. But the second time, I checked multiple times if they were as they supposed to be. After I replaced the parts it worked well for about three months. It's possible for them to get loose in time?
RE: Filament Leakage - MK3S+
How scratched should the surface be? Some minor scratches count?
Even a tiny scratch on one of the mating surfaces is enough to start a leak then, if left, the high pressures can erode a deeper flaw.
Cheerio,
RE: Filament Leakage - MK3S+
I checked my cleaned pieces for any scratches but I haven't found anything yet. As I don't have much experience, there might be some tiny minor scratches which I'm missing, so I uploaded some photos of each mating surfaces(the nozzle's and the heatbreak's) I hope they're useful. 🙂
RE: Filament Leakage - MK3S+
remember to torque the nozzle heated according to Prusa, please.
I recommend to use a nozzle of good quality, like from Prusa or E3D as @diem said, not a dirt cheap one. It is THE essential part of every FDM printer. If you mainly use PETG and PLA, a brass nozzle lasts for months. I have my hard coated brass nozzle from Micro Swiss for ages in my MK3S.
RE:
Your mating surfaces could be cleaner. Do you have very fine sandpaper (something finer than, say, 300, ideally 1000)?
RE:
Hey blauzahn
I want to make clear that I have all the parts form Prusa. I know from experience how many problem can a low quality piece cause. Therefore, with all the pieces bought from Prusa shop, there shouldn't be any problems with them. About the sandpaper, I'll look and see if I have some and try to make the surfaces cleaner
The area at 7 o'clock in the second picture looks suspect - but all these defects are easier to feel than to see ... run a fingernail over them to check for irregularities and, as @blauzahn says the surfaces must be clean - a blowtorch can help in some cases.
Cheerio,
RE: Filament Leakage - MK3S+
After I cleaned them, the next step would be to assemble everything back and see what happens. Is there any specific order in which I should put the things together? Or anything I should pay close attention, except this diagram?
RE: Filament Leakage - MK3S+
Because I didn't receive any reply I decided to reassemble it again and see what happens. Everything was cleaned so I tightened the nozzle and the heatbreak as shown in the Prusa diagram. I also applied some thermal paste on the heatsink and ran a first print, but the same result. I couldn't even finish the print because the filament was already leaking which also triggered a Z axis error, so I had to stop the print. I don't understand what I did wrong because the nozzle and the heatbreak were tightened and looked fine. Also, if you could tell me where the black filament comes from it'd help me a lot.
RE: Filament Leakage - MK3S+
the E3dV6 extruder setup is simple but critical,
it relies upon the flat end surface of the heatbreak, being tightened against the flat end surface of the nozzle
this is difficult to achieve with a contaminated heater block
in the past, I have disassembled the heatblock, nozzle and heat break, cleaned the external threads with a brass wire brush, a pair of pliers and the gas ring on my cooker, and cleared the internal thread in the heat block, with an M6 tap 'Metal cutting tool'
then re assembled the parts carefully...
I departed from normal process, by using 'CoppaSlip' High temperature antisieze grease on the nozzle and heatbreak threads, then screwed the nozzle fully into the heatbreak, then backed it out half a turn, next I screwed the heat break fully into the opposite side of the heatblock, until it butted against the back of the nozzle, tightening it lightly on place, next I put some heat sink paste on the larger threads on the heatbreak and screwed the heat sink, into place. ensuring that any excess paste was removed from the gap between the heatsink and the heatblock.
I then re inserted the PTFE Tube and re assembled the printer extruder housing around the extruder.
when assembled, I Put some protective paper over the printer heatbed and heated the nozzle to 280C, before finally tightening the nozzle.
finally I reduced temperatures to normal printing temperatures and loaded some filament, being careful to catch the first spurt of filament in a tissue, because it would probably contain some Coppaslip, and I didn't want that to contaminate my build surface.
after that I removed the paper covering the heat bed, re installed the removable build plate, and executed a 'First layer calibration print' I prefer to use the
'Life adjust 'Z' My Way' process, than the prusa built in option.
https://forum.prusa3d.com/forum/original-prusa-i3-mk3s-mk3-assembly-and-first-prints-troubleshooting/life-adjust-z-my-way/
there are test files in the bottom of the first post, for use with 0.4mm nozzles
the black filament seems to be the charred remains of filament that has leaked through the screw threads in the heater block.
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: Filament Leakage - MK3S+
@COSMOS: I had not seen your post yet. Sorry. I just received a notification about the new post from @JoanTabb a few minutes after she had posted her nice instructions.
When tightening the nozzle, you counter the torque by gripping the heatblock, not the heatsink. Usually this works. It helps, when the heatbreak itself is fully screwed onto block into the heatsink. Does your heatsink sit tight in the extruder housing or does it rotate too easily? As @JoanTabb states: Thermal conductive paste has to be applied to the thread of the heatbreak that goes into the heatsink. But only there, not to the thread that goes into the heatblock. The heat that goes into the heatbreak should be minimised. OTOH, the heat it can loose to the heatsink maximized.
When tightening, I use a pliers wrench and grip the heatblock between its front and back surfaces in order to stay away from the fragile cables. I prefer a pliers wrench over a plain wrench because it does not slip. Since the middle of the heatbreak is thin and fragile, one has to be careful not to bend, break or snap it. This happened to me once. I use a torque screwdriver to tighten the nozzle hot.
At work, I also managed to wreck the thread within the heat block once and had to replace it. At home I use a nickel plated copper heatblock from E3D. Like @JoanTabb, I use copper paste (used for cars exhaust pipe screws). Also only for the thread between nozzle and heatblock.
I have set of spare parts (nozzle, heatblock, heatbreak). Just in case. Of course one can always order a fully assembled hotend from Prusa. But that is more expensive and you have to disassemble more in order to route the cables into he electronic box.
Please be patient. At the end you will get it to work properly again.
RE: Filament Leakage - MK3S+
Thanks a lot @blauzahn and @ joantabb for the detailed response, they really help me a lot. After I read your post, I suspect there is a problem with the heatbreak, which had not been changed before. As I didn't have a brass brush, I cleaned them using a small micro drill and a mini brass brush(it wasn't very strong. for example you could stop it with your finger), but it might had done some minor scratches trough which the filament could leak. Anyway, I'm going to buy a new heatbreak and a brass brush so I can clean the parts more easily, replace, again, the nozzle with a spare one and clean the heatblok on the inside. I checked if the heatsink was sitting tight and yes it did. After I get a new heatbreak I'll try again and hopefully it will work, but for now I'm going to wait for the heatbreak. Thanks again for all your responses. 🙂