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marc.d6
(@marc-d6)
Active Member
MM Layer issues

The blue one was my first print the red was my second. You can see the layer problem isn't just one color it goes across several which makes me wonder what it could be. If it was one color I would say the spool got stuck or whatever but a few, well I'm not sure. You can see through most of the print the layers are fine it's just those "gaps". No issues with single extrusions prints so far but have only tested two.


Posted : 06/01/2018 7:43 pm
seth.g2
(@seth-g2)
Trusted Member
Re: MM Layer issues

Okay, so I've personally seen this a few times, this is one of my own prints and I've seen other people have it happen to them as well.

I believe it is a feed path resistance problem in the multiplexer. It wouldn't appear as much in a single color print because the filament doesn't retract all the way into the steel tubing if there is no color changing.

My personal issue was coming from the combining part of the feed paths where the tolerances were too small to let in improperly shaped filament.

Eventually it fully jammed and broke.

I did a redesign to the multiplexer that has worked for me and a few others so far. I'd be interested to see if it works for you as well.

I suggest printing the monoplexer as a backup as well, just in case. Here's the link to the topic here on the forums which have direct links to the pages with the STLs:

https://shop.prusa3d.com/forum/original-prusa-i3-mk2-multi-material-f26/monoplexer-and-multiplexer-redesigns-no-metal-part-t12801.html

Hope it all goes well!

Posted : 06/01/2018 11:01 pm
marc.d6
(@marc-d6)
Active Member
Topic starter answered:
Re: MM Layer issues

Thanks for the link, I'll have to print one off see if it makes a difference. Looking forward to giving this a try.

Posted : 07/01/2018 4:07 am
ntdesign
(@ntdesign)
Reputable Member
Re: MM Layer issues

Let us know how it goes. I'll try it too as soon as I have time.

Posted : 08/01/2018 2:39 pm
marc.d6
(@marc-d6)
Active Member
Topic starter answered:
Re: MM Layer issues

I will be printing both of these in the next few days and will give it a try this weekend.

Posted : 09/01/2018 2:55 am
Dewey79
(@dewey79)
Honorable Member
Re: MM Layer issues

With the MMU having problems can you at least print with supports or water soluble supports?

Posted : 10/01/2018 2:24 am
marc.d6
(@marc-d6)
Active Member
Topic starter answered:
Re: MM Layer issues


With the MMU having problems can you at least print with supports or water soluble supports?

I haven't tried soluble material yet and since the MMU I haven't tried printing anything with supports so far.

Posted : 11/01/2018 1:40 am
marc.d6
(@marc-d6)
Active Member
Topic starter answered:
Re: MM Layer issues

So I was able to give Seth's multiplexer a try and must say it worked very well. Seth is correct, the tolerances are too tight, the metal tube is restrictive. These pics are right off the printer with just a few small strings to clean. I am very pleased with the results and want to thank Seth for his design. The simplicity just makes sense. Single filament prints with the mux were no problem either. the pictures are my second attempt, the first lost adhesion to the bed about 3/4 of the way through so it didn't make it. I will post the time lapse videos here when I get them uploaded.

Edit:
The videos of the two prints. You can see the lifting on the first one of the wipe block but the second one isn't nearly as bad.

Posted : 20/01/2018 3:17 am
seth.g2
(@seth-g2)
Trusted Member
Re: MM Layer issues

Glad I could help 🙂

Posted : 21/01/2018 4:08 am
marc.d6
(@marc-d6)
Active Member
Topic starter answered:
Re: MM Layer issues


Glad I could help 🙂

That you did and thank you very much.

Posted : 25/01/2018 1:42 am
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