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wrong filament change on single color print  

New Member
wrong filament change on single color print

Hello, I have a prusa i3 mk3s with mmu2s.

Im currently printing a single color piece and randomly it asks for filament change to the same color like if i pressed the control and selected swap filament or something. It then ask's to confirm filament loaded ok.

I have times this does not happen (no change in gcode what so ever).

I am using octoprint.

What can it be?


Thanks in advance

Posted : 16/09/2021 10:21 am
Illustrious Member

I am new to MMU2S.  I have not seen this yet on my printer,  I would check the gCode.  

Chuck H
3D Printer Review Blog...
Posted : 16/09/2021 10:29 am
New Member
Topic starter answered:
same gcode sometimes prints ok

Same gcode yesterday printed all nicely not even a single stop.

It happens randomly with other gcodes algo.

For everybody convinience and help, uploaded the gcode.

Posted : 16/09/2021 10:41 am
New Member
RE: wrong filament change

I have seen the behave in earlier time you describe as well on my printer config too. I noticed that it had not to do with single or multimaterial config. At least in my case. 

I my case I had to admit that Finda and Filament sensor where not properly adjusted.

I upgraded as follow:

As you can see I upgraded to my printer a Stat indication on Filamentsensor on the extruder as well on mmu. After that fine adjustment during print never happend again a filament change.

I noted before that Upgrade a short flashing (pull down/Up of thoose Sensor ) forced the mmu2 to change filament. 

If using Octopi you have to ensure that in config there is 5 Extruder with shared nozzle configured. Also that can cause several strange behave of Filament change. 

You Gcode I quickly looked over and on first look didn`t see anything wrong --> but really just looked over fastly. 

At the moment I am struggeling with an really anoying issue, and I don`t know if you can find your case in it?

If you are electrically able you can implement a switch into the Filament sensor ans MMU sensor, and simulate a pull up/ down State to Rambo as well mmu Board, and simulate what habend when by time one or the other Sensor gets interuptet or activatd. It shows you on straight way by doing the behave of MMU like it would be if a sensor gets changing during print. A pretty help ful 2 understand how mmu2 behaves. 



This post was modified 2 months ago by fhartmann
Posted : 28/09/2021 9:06 am