yesterday I did a simple print and something went wrong. I can’t check the footage yet but as I came back to the printer I found a big blob of filament. In this blob the silicone sock of the extruder was embedded, ripped apart by pressure. Now the extruder nozzle is covered in plastic (see images).
This is a 0,4mm stainless steel nozzle, the filament is Bambu Labs Blue PLA.
Is there a way to remove the filament and get the nozzle back to work or should I scrap it? If the latter, where can I get a stainless steel replacement nozzle? I occasionally print with embedded magnets and I couldn’t find stainless steel nozzles anymore in the Bambu Store.
To answer your question - yes, it can be cleaned. I’ve salvaged nozzles that were far worse than what you’re showing.
The questions you didn’t ask, but are worth considering, are these:
Does it actually need to be cleaned?
Probably not. If the silicone sock still fits and the thermistor is reading correctly, I would be inclined to leave it alone.
Even if you clean it, is it worth the time and effort?
In many cases, probably not. If the nozzle is still functioning normally, the benefit of cleaning it may be small.
I completely understand the urge to fix something that looks messy. I’ve spent plenty of time salvaging nozzles myself, and in hindsight the $15 replacement cost was usually cheaper than the hours I spent trying to make them perfect again.
That said, I would never discourage someone from trying this kind of salvage at least once. There is real value in learning how the hotend behaves and seeing what can be recovered. If you enjoy the tinkering side of 3D printing, it can be a useful exercise.
On the other hand, if you prefer your printer to behave more like an appliance, replacing the nozzle is often the simpler path.
With respect to stainless steel nozzles, Bambu isn’t the only seller of Bambu nozzles. I find plenty of them on Amazon, Ali express and ebay.
@Arnd I will give that a try! Maybe one of my neighbours has a heatgun I can borrow, great idea!
@Olias Those are some very good points to consider. I ordered new silicone socks yesterday. As soon as they arrive I’ll test out if the nozzle still works. What is already bothering me is the smell of smoldering plastic that comes from it. I’ll try to clean it up a bit and will give it a go.
Does that “plastic coating” that will be still present even after a cleanup will increase the chance of that thing catching fire or will it decrease print quality/reliability?
Rest assured, you will become nose-blind to that smell very quickly and the only people who will notice are people who are not in that environment every day.
Simple answer; No.
Think about it. Hot molten filament coming out of the nozzle is a standard function of the printer. The tip is far hotter than the sides, so if there were ever a fire hazard it would occur there first. But the temperature required to burn PLA, PETG, ASA, ABS etc. is much higher than the nozzle temperature.
That said, you may be concerned about the silicone sock becoming a thermal insulator and increasing the temperature inside. That is part of its function - to retain heat - but it would still have to reach temperatures 200-300 C higher to approach anything close to combustion. When you hear about 3D printers catching on fire, it is almost always related to power supplies or faulty wiring, such as the A1 issue in 2024.
On the subject of reliability, that is a very real concern, but you can calibrate around it if your models appear degraded. Otherwise, it should not be a concern. If the amount of accumulated filament has somehow dislodged the thermistor - unlikely - then you may be getting false nozzle temp readings. If it is, perform a simple temperature tower test and recalibrate your nozzle temperatures. If you’re unsure how to do that, I can share some tutorials that worked for me.
There won’t be a chance of fire, but it’ll melt and ruin a print.
I’ve cleaned worse. Give up on the thermistor and heater. Heat the nozzle up using a heat gun and gently pull the thermistor out. Scrape any hot filament away from that tiny hole. It get’s plugged easily. There’s another on the other side. It’s fixable if filled in, but you don’t really want that headache now.
Once that hole is clear, I have used a brass brush to push heated filament off the throat. Brush away from the heatsink and wipe with paper towel when needed. Keep the nozzle hot with the heat gun. It won’t be an all one swipe and done process but won’t take too long. Eventually you’ll have a nice clean surface again.
While your brushing towards the nozzle end be certain to not allow build up on it. scrape horizontally to the nozzle to remove any build up there. Brass will not harm the nozzle.
Once you have a clean surface apply a heater and thermistor. Sock as well, but not necessary at this moment. Heat up the nozzle to 200-210 and try to load some filament. While or just before carefully observe the nozzle. Any smoke coming off it. If so it’s just plastic you missed and you can most likely remove it with a paper towel. Just don’t burn yourself.
Filament comes out, you’re golden. Slap a sock on it and be on your way. Don’t overthink it. It’s a good idea to keep socks, thermistors, heaters as well as a spare nozzle on hand so there’s little to no downtime when this happens. It will happen again, at some point.
I wanted to give an update on the subject. But first thank you guys for your answers, they really helped me a lot!
Yesterday the heat socks came in the mail so I gave the cleaning a try today. I got a heat gun from my neighbor, picked some pliers and tried to clean the nozzle.
I’m pretty happy with the result. I don’t know if it could be more clean, but I couldn’t manage to do so. I avoided to get the heat element and the thermistor out, because I don’t have replacements on hand.And I did not have a brass brush either. Just wanted to try. After that I put on the silicone sock and did a standard benchy print with 124% speed just to test things out. And it looks as if the thermistor and the heat element work just fine.
Should I clean the nozzle more thoroughly or will this be enough? Whats your opinion on it?
Now that you have it all back together if you wanted to get it super clean, Just install it, and set the printer to 260. Unwrap the sock with hot gloves, and wipe it down while it’s all still melted.
That is a matter of personal preference and how much time you’re willing to spend.
When I had my first blob-of-death, I went super OCD on cleaning. My method was to deep-freeze the nozzle in the back of my freezer and then chip off the PLA, which becomes brittle at cold temperatures. Then I used a Dremel with a brass wheel to clean off the remainder. Brass is softer than stainless steel, so it did not damage the nozzle.
I also replaced the thermistor, which was its own adventure because once the factory thermal paste cooks, what you get is a hard, crumbly material. The only way to extract it was to use a hand drill to clean out the thermistor from the hole in the side of the nozzle and replace it with a new one.
This time I used a better thermal grease that I normally use on CPU heat sinks rather than the factory supplied thermal paste. It cleans up better later on.
After I was done with all of that, I had what looked like a factory-new nozzle that only under a loupe would one see any evidence of salvage. I was mighty proud of myself until I looked at the clock. I spent four hours salvaging a $15 nozzle. The kid at the local McDonald’s makes more. But I had the satisfaction of knowing I could do it. Would I do it again? HｅｌｌNo!!!
The Maker spirit
Anyone with the true spirit of a maker knows what I am talking about. Sometimes when something breaks and you know you can troubleshoot it, but it is taking longer than you hoped, it eventually becomes personal. Now you have to beat the machine, even if it means wasting an entire afternoon. I am sure I am not alone in that feeling.
But I had the satisfaction of knowing I could do it. Would I do it again? HｅｌｌNo!!!