Nozzle cleaning consistently failing with FLEX filament
I just spent a lot of money upgrading my MK4 to CORE ONE, only to find out that I can't print with FLEX filament anymore. What good is my printer if I can't get past the 'Nozzle Cleaning' stage. I have the latest firmware (6.3.4 + 18511) and have no problem printing with any other filament, but with FLEX its a nightmare. I have tried lowering the temperature in the start G-code, but that doesn't seem to work either.
It's crazy to have a 'new feature' (nozzle cleaning) forcing me to jump through hoops to do simple printing. Right now I have a very large, very expensive paperweight. There needs to be a way to bypass the nozzle cleaning test, if it continues to fail.
RE: Nozzle cleaning consistently failing with FLEX filament
I've yet to try TPU in my Core One (Bowdens and TPU aren't a great mix, sigh). As for nozzle checks, and I'm guessing here, if its high temp TPU there is a Slicer setting for the filament preheat/idle temp; if the TPU isn't malleable during the cleaning, you might try raising the idle temp.
Hopefully someone who has been successful printing TPU/FLEX can provide better info.
RE: Nozzle cleaning consistently failing with FLEX filament
I don't have any difficulties at all threading 95A TPU through the Bowden tube and through the filament sensor. For the softer TPU, you'll have to remove to Bowden tube and feed it directly into the extruder, then the next problem is getting past the filament sensor. I saw a mod on printables to replace the filament sensor spring with small magnets which allows easier insertion.
RE: Nozzle cleaning consistently failing with FLEX filament
Arrgg... editing seems to be broken. What I wanted to add, for the nozzle cleaning problem, the forum consensus is that EMF from the PWM signal to the heater element is inferring with load cell readings which causes this problem. The work-around that people have found successful (including me) is to turn off the heater prior to doing the nozzle cleaning set. In the Start G-code section would add the following:
M84 E ; turn off E motor ; ; Added - turn off temperature ; M104 S0 G29 P9 X208 Y-2.5 W32 H4
RE: Nozzle cleaning consistently failing with FLEX filament
Wow! That actually worked - THANKS!!! However, that kind of begs the question - Why does it succeed with other filaments? I have successfully printed with PETG, ABS, PLA and PCTG so far. Only TPU gave me problems with nozzle cleaning.
RE: Nozzle cleaning consistently failing with FLEX filament
Wow! That actually worked - THANKS!!! However, that kind of begs the question - Why does it succeed with other filaments? I have successfully printed with PETG, ABS, PLA and PCTG so far. Only TPU gave me problems with nozzle cleaning.
Not really sure other than to think (guess) that since TPU is "squishier" that it's harder to get an accurate load cell reading? Anyway, I had this problem with PETG as well so I leave it in. Alternatively for nozzle wiping you can use this method instead (which is better): Prusa CORE One Nozzle Wiper
RE: Nozzle cleaning consistently failing with FLEX filament
Last night I was getting nozzle clean failures again with TPU, so I followed an earlier suggestion and reversed the build sheet on the plate (exposing an unused corner for the nozzle clean step) and this allowed the nozzle clean to succeed. Then I inspected the original front right corner and discovered I had some TPU residue there, which undoubtedly caused the original failure. So I guess this bolsters the 'too squishy for the load cell' theory.
I've also ordered the parts for the Prusa Core ONE Nozzle Wiper mod - and we'll see how this goes. What I don't quite understand is why Prusa insists on the nozzle clean step, even though there is plenty of evidence that it is a) unnecessary in most cases, b) unreliable with FLEX filaments (and apparently others as well) and c) pissing off loyal Prusa customers.