Load/Unload during MM prints ok. Unload end of single material fails
 
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brendan.s7
(@brendan-s7)
Active Member
Load/Unload during MM prints ok. Unload end of single material fails

Hi,

I have got my multi-material prints nice and stable. For the last round of prints with 60-90 filament changes without any problems.  However when I do a single material print, at the end of the print, I ~50% of the time get a filament jam unloading.

I note that end GCode:-

{if has_wipe_tower}
G1 E-15.0000 F3000
{else}

Why is this note needed on when I do not have a wipe tower ?

Any other suggestions ?

I am running the latest firmware (3.7.1) and using PrusaSlicer 2.0.0-rc+linux64. With two type Prusament  filament (same thing happens black PLA, white PLA and non-prusament PLA)

Regards,

Brendan

 

This topic was modified 3 years ago by brendan.s7
Posted : 02/06/2019 4:15 pm
Lichtjaeger
(@lichtjaeger)
Noble Member
RE: Load/Unload during MM prints ok. Unload end of single material fails

The filament settings for single and multi-material are different. In expert mode check the advanced options of the filament for multi-material and change those settings in single mode to match.

Posted : 02/06/2019 5:53 pm
petr.f12
(@petr-f12)
Active Member
RE: Load/Unload during MM prints ok. Unload end of single material fails

I am dealing with the same problem. I've tried to customize the single mode filament settings according to the MMU mode settings but they seem to be ignored. At the end of print just some chaotic moves are made resulting in filament uload failure every third print. The printer just stalls with the nozzle heated up waiting for user intervention. Quite unpleasant behaivour especialy when you are not nearby the printer at the moment. The printer even doesn't react on remote commands at this state thus no posibility to turn off the heating remotely (e.g. Octoprint Anywhere).

 

Posted : 28/06/2019 9:10 am
gnat
 gnat
(@gnat)
Noble Member
RE: Load/Unload during MM prints ok. Unload end of single material fails

That's bizarre. Typically single mode can work fine while multi mode will have trouble. For it to be backwards seems weird and anything I can think of (FINDA, filament slipping in the gears, etc..) should be happening in multi mode too.

Does this happen from all the filament paths or just one? When you remove the filament, what does the tip look like compared to how a tip from a multi-tool job looks post extraction?

MMU tips and troubleshooting
Posted : 28/06/2019 2:35 pm
petr.f12
(@petr-f12)
Active Member
RE: Load/Unload during MM prints ok. Unload end of single material fails

It has nothing to do with sensors. I use modified variant of them (longer IR sensor arm and magnet below ball for FINDA) and they are very reliable now. The reason of this failure is obvious. It is an ugly filament tip which cannot go through that orange part below the entry of PTFE tube between the extruder and the MMU unit. Filament is unloaded from the extruder and the MMU tries to unload it further but cannot pull it through that narrow path. After the MMU stops dragging I am able to cut the filament in front of the MMU push it back towards the extruder and cut the tip. Then I have to pull some filament from the MMU to cut the ground part. Than after pushing the MMU middle button normal operation is restored and print is finished. 

In MMU mode I have nice cone-shaped filament tips.

So question is, why in MMU mode there are different moves which form nice filament tip while in single mode there are only several quick back and forward moves of an extruder motor which form ugly tips prone to unload error? I've tried to mimic the Filament unload settings from the MMU mode settings to the single mode settings without any effect to those before unload extruder motor moves.

Posted : 30/06/2019 8:59 pm
Holger
(@holger-2)
Honorable Member
RE: Load/Unload during MM prints ok. Unload end of single material fails

Hi,

I observed the same difficulties even when using S3D. A change of the user end gcode, incl. ramming sequence, was my solution for this issue.

; Filament-specific end gcode
M83 ; extruder relative mode
G92 E0 ; reset extrusion distance
G1 X0 Y210 F7200
; CP TOOLCHANGE UNLOAD
G1 F1600
G1 E0.3085
G1 F1687
G1 E0.3252
G1 F2261
G1 E0.4359
G1 F2904
G1 E0.5599
G1 E-15.0000 F9000
G1 E-24.5000 F5400
G1 E-7.0000 F2700
G1 E-3.5000 F1620
G1 E20.0000 F267
G1 E-20.0000 F283
G1 E20.0000 F299
G1 E-20.0000 F316
G1 E20.0000 F332
G1 E-20.0000 F348
G1 E20.0000 F364
G1 E-20.0000 F380
G1 E20.0000 F397
G1 E-20.0000 F413
G1 E-35.0000 F2000

M702 C

G4 ; wait

2x Personal MK3IR-BMG09 (Full) BEAR + MMU2S mod., ...

Posted : 30/06/2019 9:14 pm
DJ
 DJ
(@dj-4)
Active Member
RE: Load/Unload during MM prints ok. Unload end of single material fails

I'm having the same issue when using "Original Prusa i3 MK3S MMU2S Single" - see attached picture.  I have to cut the filament at the MMU and pull it out from the extruder door for nearly every "Single" print.  I'd like to say I have great success with MMU2S printing, but that's a different issue.  Is manually changing the Gcode the only fix?

DJ

Posted : 06/05/2020 9:49 pm
tg73 liked
Tankred
(@tankred)
New Member
RE: Load/Unload during MM prints ok. Unload end of single material fails

Holger, that worked for me. Thank you for solving this. I guess there is no a way to modify the printing settings accordingly in Prusa Slicer?

Posted : 23/05/2022 9:06 am
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