Problems when replacing the nozzle
I was having trouble replacing the nozzle. I probably haven't figured out the correct procedure for changing the nozzle yet, as I get the thermistor error sometimes (but after restarting there doesn't seem to be any problems).
In this case, after printing for an hour, i noticed the filament leaking between the nozzle and the heater block, so I unscrewed the nozzle, trying to clean it and then reassembled it. In this case is it a safe procedure or should the heater block/hotend be cleaned in some way?
These are the steps I follow:
- heating the nozzle to 280° (the filament is already unloaded)
- when it has reached the temperature with the wrench I block the heater block and unscrew the nozzle (here sometimes the alarm appears and the printer resets) - i am careful not to touch the wires
- I take the nozzle and hold the wrench and screw it back, bringing the temperature back to 280 °
Now here it is not clear to me where I am wrong ... maybe I do not screw the nozzle enough? I did not understand if you have to "screw" the heater block ... because in some videos I see that they rotate it, but I don't understand its usefulness.
In any case, if there is some filament left between the nozzle and the heater block, how can I clean it with the nozzle inserted? Is it useful a cold shot?
RE:
The procedure described here, to perform an heat break check, is it possible without the nozzle assembled?
https://help.prusa3d.com/en/article/clogged-nozzle-hotend-mini-mini_112011
PS.
How do you clean a nozzle from filament residues along the screw?
https://help.prusa3d.com/en/article/changing-replacing-the-nozzle-mini_134235
Pay particular attention to the diagrams in the 'Final inspection' section.
Where did you get the replacement nozzle? Be aware that some cheap nozzles are fractionally too short in the thread to seat correctly.
Cheerio,
RE:
Yes the space between nozzle and heater block was correct.
I'm replacing with a E3D V6 copper nichel plated nozzle... get from an european reseller.
PS.
One thing is not clear to me. Do I also have to push the heater block up (as final step when it's hot at 280°C)?
RE: Problems when replacing the nozzle
Is this correct?
RE: Problems when replacing the nozzle
This is correct — if the gap comes about because you can't screw the nozzle in any further. In that case, the nozzle hits the heat break and should form a seal. If you just stop screwing it in to create the gap, it's wrongly assembled.
I take the nozzle and hold the wrench and screw it back, bringing the temperature back to 280 °
Not sure how to parse this sentence. If you're screwing the nozzle in and then bring the temperature up, that's not enough. You have to *tighten* the nozzle at 280 (I actually use 285 but it shouldn't matter).
How do you clean a nozzle from filament residues along the screw?
Hold it with pliers in front of a heat gun, wait until the filament becomes soft, then use a soft brass wire brush (e.g., https://www.amazon.com/gp/product/B0829ZTN57/) to clean it. I've made this part of my nozzle replacement ritual. Heat up the nozzle and clean off any filament residues.
as I get the thermistor error sometimes
This happens when you shorten the wires with the wrench. If you find yourself changing nozzles frequently you may want to check out the Z-catch tool ( https://z-catch.com/). Works fine for Mini and Mk3S. It's a bit pricey but destroying your thermistor cable gets old after a while. And if you're really into swapping nozzles, I'd consider replacing the hotend with a Dragon hotend.
Formerly known on this forum as @fuchsr -- until all hell broke loose with the forum software...
RE: Problems when replacing the nozzle
Hi fuchsr
Not sure how to parse this sentence. If you're screwing the nozzle in and then bring the temperature up, that's not enough. You have to *tighten* the nozzle at 280 (I actually use 285 but it shouldn't matter).
Yes, that's exactly what I meant.
Now i have cleaned hotend again (made a cold pull without PTFE tube), retight everything, cleaned the nozzle and reassembled it.
I'm starting to think I didn't hold it tight enough (I changed the tool I used to tighten it).
Also before, I used the wrench, and I couldn't hold the heater block firmly; now I have tried with pliers and I feel much more comfortable (and received no red screen).
Disassembling and reassembling is a hassle, but I think it is the only way to learn how to perform the various procedures well.
Tonight I do the calibration again (the fact that now the automatic calibration shows me a too low z level gives me hope).
Hold it with pliers in front of a heat gun, wait until the filament becomes soft, then use a soft brass wire brush (e.g., https://www.amazon.com/gp/product/B0829ZTN57/) to clean it. I've made this part of my nozzle replacement ritual. Heat up the nozzle and clean off any filament residues.
Thanks!
Could filament residue in the inner screw of the heater block be a problem? I have no idea how to clean there by the way.
If you find yourself changing nozzles frequently you may want to check out the Z-catch tool ( https://z-catch.com/). Works fine for Mini and Mk3S. It's a bit pricey but destroying your thermistor cable gets old after a while. And if you're really into swapping nozzles, I'd consider replacing the hotend with a Dragon hotend.
Thanks again.
Does installing a Dragon hotend require changes on the firmware or PrusaSlicer side?
RE: Problems when replacing the nozzle
Does installing a Dragon hotend require changes on the firmware or PrusaSlicer side?
No changes. You have to print a mount for it, that's all.
Formerly known on this forum as @fuchsr -- until all hell broke loose with the forum software...