Notifications
Clear all

Jet another MMU2s Issue  

  RSS
Andreas_O
(@andreas_o)
Active Member
Jet another MMU2s Issue

I have an issue with the MK2.5S, MMU2S.

 

I can't get the filament to load reliably. I've tried the Knowledgebase Suggestions but so far nothing worked.

When the printer loads the Filament FINDA and IR show filament is loaded but it is not forwarded to the hotend.

I've tried various tensions of the pully. But so far nothing worked.

When I load the Filament by pushing filament by hand through the tube I can push it through right to the hotend.

 

Any help is appriciated.

 

Kind Regards

Andreas

Posted : 26/01/2021 3:38 pm
Robin
(@robin)
Estimable Member
RE: Jet another MMU2s Issue

Where does the loading stop exactly? What do both sensors show when everything ist unloaded completely?

If at first you don't succeed, skydiving is not for you....
Posted : 28/01/2021 10:28 am
Andreas_O
(@andreas_o)
Active Member
Topic starter answered:
RE: Jet another MMU2s Issue

Loading Start:

FINDA: 0

IR:0

While Loading:

FINDA: N/A

IR:0

Loading complete:

I can see the filament going through the gears at the Extruder

FINDA:1

IR:1

The filament gets fed into the Hotend and retracts immediately.

After a few retries, the printer stops. When I cut the top of the filament most times the print continues until the next filament change.

 

This post was modified 9 months ago 3 times by Andreas_O
Posted : 28/01/2021 12:19 pm
tsamisa@cytanet.com.cy
(@tsamisacytanet-com-cy)
Trusted Member
RE: Jet another MMU2s Issue

I had something similar at some point. The problem for me was the small pfte in the hotend. It was slightly deformed but enough to cause an issue. 

Posted : 28/01/2021 7:59 pm
Andreas_O
(@andreas_o)
Active Member
Topic starter answered:
RE: Jet another MMU2s Issue

Attached some Fotos of my Printhead. Does the Tube look damaged to you? Should I replace it?

Tube Filament Tip Tube with Filament

Posted : 29/01/2021 7:53 am
Andreas_O
(@andreas_o)
Active Member
Topic starter answered:
RE: Jet another MMU2s Issue

I noticed another problem my mmu2 parts are not at the latest revision. My body is version M1. The parts one can download are on R.

It seems that I have missed an upgrade step. But it is difficult to tell which parts are correct because the ReadMedFirst file says on various parts "different form MK3S" but it is not clear which version is for which printer. 

https://www.prusa3d.com/prusa-i3-printable-parts/

Posted : 29/01/2021 10:03 am
Robin
(@robin)
Estimable Member
RE: Jet another MMU2s Issue
Posted by: @andreas_o

I noticed another problem my mmu2 parts are not at the latest revision. My body is version M1. The parts one can download are on R.

It seems that I have missed an upgrade step. But it is difficult to tell which parts are correct because the ReadMedFirst file says on various parts "different form MK3S" but it is not clear which version is for which printer. 

https://www.prusa3d.com/prusa-i3-printable-parts/

I believe the letter is just indicating if it's a prusa printed or a downloaded and self printed part. The number shows the revision... but I am not 100% sure of that and can't find it in the docs right now.

If at first you don't succeed, skydiving is not for you....
Posted : 29/01/2021 3:44 pm
tsamisa@cytanet.com.cy
(@tsamisacytanet-com-cy)
Trusted Member
RE: Jet another MMU2s Issue

Your PFTE looks ok from the photos. 

Posted : 29/01/2021 6:53 pm
Robin
(@robin)
Estimable Member
RE: Jet another MMU2s Issue

Does the extruder gear eat into the filament that fails to load? If so, you might have to much friction in your filament path causing the extruder gears to grind away the filament until it‘s thin enough to let the IR sensor switch to „0“ and causing the MMU to retract.

If at first you don't succeed, skydiving is not for you....
Posted : 30/01/2021 9:14 am
Andreas_O
(@andreas_o)
Active Member
Topic starter answered:
RE: Jet another MMU2s Issue

@robin

No that's not the case.

Posted : 01/02/2021 8:50 am
Andreas_O
(@andreas_o)
Active Member
Topic starter answered:
RE: Jet another MMU2s Issue

@robin ad: Versions of the Parts.

The M and R Version of the MMU look the same. I will replace them anyway.

My Hotend is on R4 the download version is on R5 I will replace them and see if that solves my problem.

 

Posted : 01/02/2021 8:53 am
Tosko
(@tosko)
Active Member
RE: Jet another MMU2s Issue

I have been unable to resolve this same problem. Lots of clack-clack-clack noises, nothing feeding past the MMU. I have yet to get this thing to grip and pull a single filament. I've tried with the spring tension at various levels. I can see the idler turning, the IR sensor is calibrated and functioning reliably and all my filaments are perfectly aligned with their respective bondtech gears.

I can manually push filament all the way to the hotend, with ease, so the path is clear. I even tried putting in 4-inch pieces of PTFE so I could eliminate tube-friction as a problem, but feeding 1 meter segments of PLA by hand doesn't fix it.

I've disassembled and reassembled. I've swapped in two mods that supposedly eliminate most feeding errors, but so far my MMU2S is an expensive paperweight. Also, my idler door (the one on the extruder assembly, with the long vertical panhandle sticking out of it) doesn't move at all if my tension screw is set where the manual says it should be. I thought there was supposed to be some "play" in it. But that issue is moot so far because no filament has reached the extruder.

My MK3S+ was working perfectly, printing PLA, PETG, ABS, ASA and TPU. Help?

This post was modified 6 months ago by Tosko
Posted : 27/04/2021 5:35 pm
HarleyRider903
(@harleyrider903)
Active Member
RE: Jet another MMU2s Issue

@david-martosko

I am brand new to this and just got mine up and running.  Someone a lot smarter than me will probably tell you I am all wrong, so please take this with the NOOB that I am. 

Remove the long PFTE tubes on the back.  Take a 2 foot long scrap filament and see if it feeds?  Try this with the MKS Load to Nozzle.  Any better?

Regarding that door you are talking about.  If you did the IR test and it was 0 and then with the fallen key, it was 1, that door is moving.  That long arm is what gets moved in front of the IR sensor that filament is loaded.  

On my very first go at this....  My long PFTE tubes were not in all the way so I marked them with a sharpie so I could see them in. I also had IR sensor issues. After I removed the sensor and put it all back together and check the IR 0/1 again, I started getting much better results.  I started this testing at 5:15 and I just wrapped up a few minutes ago around 945. 

Good luck!

Posted : 29/04/2021 3:06 am
Tosko
(@tosko)
Active Member
RE: Jet another MMU2s Issue

My IR sensor is working fine and I also subbed in 5-inch PTFE tubes so I could monitor more closely what's going on. It's still making three kinds of god-awful noises and the only way I can get filament to the hotend is to push it through by hand.

I'm going to set aside some time to undo this upgrade. The only question is whether I can get my money back. 

Posted : 29/04/2021 1:57 pm
Share: