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Need help with upgrade install on MK4  

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featherz
(@featherz)
Eminent Member
Need help with upgrade install on MK4

Just upgraded MMU2s to MMU3 and added it to my MK4. Made sure to use only the new parts provided and filament sensor calibration passed fine. Also did the gear alignment and any other calibration the printer asked for. The Finda is detecting the filament as it should. Filament loads and extrudes properly. Initially. 🙂 

I can't seem to print for more than 1-2 color changes before the filament will jam in the nextruder - it even has wrapped around the gears a few times! I disassembled the nextruder, made sure the o-ring was still there and the gold ring was facing the correct way but now I am stumped. I tried multiple filaments (that work fine on my other non prusa you-know-who printers) and threw up a prusament as well. Loads well and prints at first, but during printing it gets scrambled - bent, wrapped around, etc.  All the tubes and festos were changed to the ones that came in the upgrade kid. I do have an obxidian nozzle on, but other than that this is stock. 

Any ideas? Likely something too tight, too loose, or misaligned, but it all 'looks' ok. Have adjusted the tension screws - no dice. 

 

Forgot to mention - whatever the second color is in my print will throw down a big blob on the purge block to deal with. First color is fine. Very odd. 

 

 

Veröffentlicht : 01/05/2024 6:39 pm
jseyfert3
(@jseyfert3)
Reputable Member
RE:

What do you mean the second color will throw down a bib blob on the purge block to deal with? Do you have a picture/video/more detailed description of what it does?

What are you printing? Did you try to print the pre-sliced gcode sheep as a test?

Veröffentlicht : 01/05/2024 7:25 pm
featherz
(@featherz)
Eminent Member
Themenstarter answered:
RE: Need help with upgrade install on MK4

Yeah will post a pic on my next try. It lays down one layer of the purge block in red for instance, then on the change to black, black spits out a huge blob before moving on - which used to happen on my MMU2 if one of the sensors was borked. But my sensors read correct here. I was trying the sheep, now I have the two color benchy in the works - had to open the nextruder again and clean out the filament dust. I'm sure something is misaligned somewhere! 🙂 

Veröffentlicht : 01/05/2024 7:31 pm
jseyfert3
(@jseyfert3)
Reputable Member
RE: Need help with upgrade install on MK4

I didn't have the MMU2, but the large blob you stated reminded me of trying to do "manual MMU" prints with a wipe tower. Some of the settings, if not changed, caused it to extrude a giant blob on the wipe tower while not moving the print head. This lead to issues later with collisions.

I've only had my MMU3 running since last Friday evening, but it hasn't made any blobs. It does occasionally sit still over the wipe tower, but if plastic is coming out the print head is moving and it never spits out any blobs. The pre-sliced sheep worked well for me, then I printed a flock of 20 sheep in one go, that worked well, so I did some purge calibration and then did a 1d8h print with ~1430 filament changes, and that worked great too (at least as far as the MMU3 was concerned, I should have had a couple of supports in a couple areas...)

Long way of saying blobs certainly aren't normal. I have a stock MK4 with stock MMU3. 0.4 mm obxidian nozzle, the MK4 version from Prusa, not a V6 nozzle on adapter. Latest version of PrusaSlicer, firmware 6.0.0 (not 6.0.0-RC) on the MK4, and the latest MMU3 firmware on the MMU3.

Veröffentlicht : 01/05/2024 7:40 pm
featherz
(@featherz)
Eminent Member
Themenstarter answered:
RE: Need help with upgrade install on MK4

Yeah it's probably my fault somewhere - my guess is somewhere in the nextruder but I have gotten pretty good at taking that apart and putting it together again. Never seen filament wrap around the gears like that! (Oh and yes, that annoying washer is in place - it likes to fall out but it's there!). 

Still fussing with it- I had the MMU2 running well so I am determined to fix this 🙂

 

Veröffentlicht : 01/05/2024 7:44 pm
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