How do we know when it is time to replace the nozzle?
Hi, Prusa Support has checked the hot end and there is no leakage. Yet, I keep getting prints with imperfections. For example, black dots, burnt marks, extra filaments suddenly showing up from nowhere in the middle of the print jobs and got pushed around by the nozzle. Sometimes they ended up brown/dark burnt balls but often they got embedded in the prints (often at the front edge or edge of a big circular hole) as brown/dark burnt filaments. I have the i3MK3S for 1.5 years. Often print PETG. For the past three months, suddenly I see more prints with small blobs and zits on the print surfaces. As far as I am aware of, there was no such blobs and zits issue in the past. Are these imperfections caused by the nozzle? If not, what caused the issues?
How do we know it is time to replace the nozzle? I have never taken the nozzle out to clean it but I have been cleaning the hot end.
RE: How do we know when it is time to replace the nozzle?
In your situation, I'd replace it. If that fixes the problem, you know it was the old nozzle. Clean it or toss it. If it doesn't fix the problem, use the removed nozzle as a spare and continue troubleshooting. Nozzles are one of the easiest things to swap, inexpensive, and often the source of annoying problems that can be hard to troubleshoot. When in doubt, swap it out.
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RE: How do we know when it is time to replace the nozzle?
Thanks. I worry that if I don't tighten it properly, I may break the hotend which will end up an expensive replacement or cause lava flow.
RE: How do we know when it is time to replace the nozzle?
Thanks. I worry that if I don't tighten it properly, I may break the hotend which will end up an expensive replacement or cause lava flow.
You don't need to be overly worried. Just be sure to immobilize the heater block with a 16mm spanner/open wrench so it can't twist and all should be well. Don't use too much pressure -- I use two fingers to tighten the nozzle -- and be sure not to twist the hotend assembly. Be sure that when the nozzle is fully tightened, there's still a < 1mm gap between nozzle and heater block and all should be well.
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He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan
In 5 years I've never changed a nozzle
After five years and thousands of prints, I have never once changed a nozzle. I have tons of them. I bought extras thinking I would need to swap out clogged nozzles, but that has never ever happened. I figured the nozzles would wear or develop some problem, based on my printer before Prusa. Of course I have swapped out 0.6mm and 0.4mm nozzles. But neither of my Prusa printers has ever required a nozzle change.
When I upgraded one of my MK3Ss to a MK4, I again bought extra nozzles. And like before, I am still using the original 0.6mm that it came with.
I print with PETG 98% of the time. ABS very occasionally, but never PLA and nothing exotic or abrasive.
Also, I did have clogged nozzles with the cheap Chinese 3D printer I had before Prusa. None since switching to Prusa.
Cheers, Tom
RE: How do we know when it is time to replace the nozzle?
Do you mean that after five years you're still using the original 0.6mm brass nozzle ?. Believe me, even if you never print abrassive filaments, I'm sure that you'd notice an improvemnt in print quality if you replaced that battered nozzle. Be merciful, the poor thing is asking for a long due retirement.. 😉
It very much depends which filaments and even which colours you print. Natural, translucent and black cause very little wear; nominally non-abrasive white and pastels contain a lot of semi-abrasive oxides and can destroy a nozzle in a few months.
Cheerio,
RE: How do we know when it is time to replace the nozzle?
I only print non-abrasive PETG and PLA and my brass nozzles will wear easily after a year. I simply carefully extrude some filament and then measure it with a caliper to see if the hole is larger than .4 and you can tell if your brass nozzle is wearing. You have to be a bit careful when you extrude to try to keep the diameter of the extrusion accurate. you’ll lose accuracy if your nozzle diameter available is larger than .4 and I found my stringing increased I don’t see a mention of the nozzle material, but I assume it’s brass