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Printer getting pickier with age?  

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Canbarelygo
(@canbarelygo)
New Member
Printer getting pickier with age?

So I’ve got a mini+ with over 65 days on the odometer since we got that update so it probably has closer to 100 days. I swapped the stock nozzle for a Midwest tungsten finally at 55 days.

I’ve noticed it’s gotten very picky about filament brand and changeovers. I primarily print petg but occasionally swap back to pla for the odd project. It basically will not print inland anymore at all and it also randomly decides to extrude inconsistently and grind filament with no obvious cause. I’ve taken apart the extruder and cleaned gears, cold pulled, etc. but it’s still not behaving predictable. Any suggestions?

default prusament pla and petg profiles are always used and I print primarily hatch box and prusament with the occasional random brand thrown in 

Posted : 14/02/2022 5:30 am
BogdanH
(@bogdanh)
Honorable Member
RE: Printer getting pickier with age?

As you said, you mostly print PETG and when you go back to PLA, it just doesn't print as it used to. Opposite usually isn't a problem (when we go from PLA to PETG). But there's explanation for this.

Main reason is filament changing process. When we unload PETG, it will be unloaded at 230°C. But we must keep in mind, that not all PETG is "sucked" out of hotend -a small amount will still stay inside. Now we load PLA at temperature, which is lower than for PETG. At that temperature PLA will melt and start coming out of nozzle, however temperature is not high enough for PETG remains, which will stay glued inside.
Yes, that's partial clog: PLA will come out, but not enough of it, because it's partially blocked by PETG remains. Extruder doesn't know about all that and will just push correct amount of filament. But because, filament is blocked, gears will start grinding on filament. Obviously, increasing gear tension is not a solution.
Solution is: if you previously unloaded PETG and you switch to PLA, then choose "Load PETG" for PLA filament. When PLA is loaded & extrudes (at PETG temperature), you can be sure that also PETG remains are being extruded. Now you unload filament and finally choose "Load PLA".
If above still doesn't work, then it's time to disassemble hotend, clean it, check PTFE tube length and replace if necessary.

[Mini+] [MK3S+BEAR]

Posted : 14/02/2022 3:34 pm
Canbarelygo
(@canbarelygo)
New Member
Topic starter answered:
RE: Printer getting pickier with age?

I have considered this and I always try to turn up the temperature over petg parameters prior to reloading and then let it push out filament while gradually cooling off to operating temp. In my mind it saves me a step and a little time lol.

however when doing that it’ll usually extrude like normal but I can definitely tell it struggles just a tad at pla temp as I usually do 3 or so purges. Then when I actually start a file it’ll essentially grind while doing the wipe and continue until I stop it

Posted : 14/02/2022 4:51 pm
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