Tried printing ASA and now the printer reboots when heating...
So I have had my Mk3 kit built for a few days - have been printing with the included PLA without issues - been very happy with the results. For some stupid reason I decided to try some ASA that I had ordered (not Prusa brand) and then the sadness begins 🙁 I used the default 260 temp, and when it started printing it was spitting and crackling and was giving off a horrible smell - I let it go for 30 minutes or so as it seemed to be printing ok - I stopped it to check it, and found the print very brittle and crumbled in my hands. It was almost impossible to get it off the bed. (looks like it has damaged the smooth surface - not the end of the world) I tried again at a lower temp, and it initially seemed to go a lot better - less smell. Then it really starting smoking, so I turned it off immediately.
Admitting defeat I went back to using PLA and had all sorts of problems - when trying to load the PLA it took quite some time before it came out in a nice flow.
I printed a test print and found that while it was waiting to heat up a clear liquid oozed out of the nozzle - When it printed there was a LOT of smoke pouring out of the nozzle, which seemed to clear up after a few minutes. The print didnt work at all - first layer was covered with a yellow residue, and was brittle. Tried again and it was better so thought it was just a matter of getting the ASA out of the system.
Went though some more testing and found that the nozzle wouldn't go above about 220 deg. Decided to do a full selftest and found that my X-axis was failing so I fixed that, and repeated the selftest. Everything is fine until it tries to heat the nozzle - now it reboots the printer 🙁
Fully own up to the stupidity of trying such a tricky filament like ASA given my lack of experience (I do know now that crackling ASA means that it probably has some moisture in it) but wasn't expecting that it would ruin the printer.
What could have happened? Seems likely the hotend is now damaged?
Do you have a multimeter?
Unplug the hotend heater from the electronics and measure the resistance of the part.
I forget the correct value but the point is there should be a low resistance, not a dead short.
I suspect you need a new heater.
It depends how confident you are with repairs. As a beginner you may prefer to change the entire hotend but probably just the heater cartridge would be enough 'though it's a trickier job. Best to get a spare PTFE tube at the same time in case damaging heat backed up with steam pressure.
Cheerio,
Cheerio,
RE:
First of all, before you print new materials check the material table ( https://help.prusa3d.com/materials ) to avoid damage to your PEI sheet (no ASA on smooth sheet without glue stick!).
Second, if you change from high temperature filament to lower temperature filament you need to clean out your hot end with the lower temp filament (or cleaning filament) at the previously used higher temperature, otherwise you risk your nozzle getting (partially) clogged.
Third, I'd recommend to only buy and use filament you find a preset for in PrusaSlicer, this way you know it's working ok. Make sure your filament is not absorbing to much moisture.
Last but not least, something is wrong with your heater/thermistor, if you have a multimeter at hand, check them out: https://help.prusa3d.com/article/multimeter-usage_2117
*edit* diem beat me to it 🙂
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RE: Tried printing ASA and now the printer reboots when heating...
So I tested the heater - reads as a dead short. I noticed that the red coverings around where the heater goes into the block are charred to a white powder, so it looks like something really bad happened to it.
RE: Tried printing ASA and now the printer reboots when heating...
So I took the entire hotend out - the Aluminium metal block looks like it started to melt - parts of it are mottled and lumpy near the nozzle. Yikes!
RE: Tried printing ASA and now the printer reboots when heating...
Sorry to continue this thread - when I was printing ASA for the second time I put my air-con on to try and blow the nasty fumes out the window - I have read that this is a big no no - could the air flow from the air conditioner have caused the block to overheat to the point where it softened the metal?
Did you by any chance turn off the power instead of stopping the print with the menu so the cooling fan stopped and the hotend heat dispersed into the part?
Cheerio,
RE: Tried printing ASA and now the printer reboots when heating...
That is possible...
Did you by any chance turn off the power instead of stopping the print with the menu so the cooling fan stopped and the hotend heat dispersed into the part?
Cheerio,