Just How Multi-Material Is The MMU2S?  

RE: Just How Multi-Material Is The MMU2S?

@igor

Thanks for sharing the pictures, very cool layer effect 😀

I think with a "large" model like that you don't need to worry about contamination between PLA & PETG, as like you said it's decorative. Contamination becomes an issue when the printed part is meant to hold some weight, for example a bracket/light-fixture/cable-holder...

Also I suspect if someone tried to pull the top/bottom of model apart (for what ever reason) the model would fail at the PLA/PETG interface, as these materials are not compatible (chemically wise) even when printed at a higher temperature 

RE: Just How Multi-Material Is The MMU2S?

@antalife

It's not that bad. In my first print I expected the tail would break off. But it survived even later paint job.

RE: Just How Multi-Material Is The MMU2S?

Here is the full video for reference:

RE: Just How Multi-Material Is The MMU2S?

@nikolai-r

Cute 😀

Have you tried using PLA body with PETG supports for models that are designed to hold some weight? For example a bracket/light-fixture/cable-holder

RE: Just How Multi-Material Is The MMU2S?

@antalife

For heavy lifting I'm usually using PETG/ABS/Nylon. PLA deforms over time pretty fast. The print orientation and design are following the purpose. Never had a case where zero gap support is required. Usually no support is required at all. But if something like that would be required, you can still reinforce your part with epoxy.

RE: Just How Multi-Material Is The MMU2S?

@nikolai-r

Fair enough

I was hoping to use the MMU2S for a cosplay prop I am making, so need the layer adhesion to be as strong as possible by default

https://www.antalife.com/2020/04/project-half-life-2-ar2-update-3.html

RE: Just How Multi-Material Is The MMU2S?

@antalife

"As strong as possible" need to be defined first :). Things like impact strength or bending. Direction of the load ... Based on that you will maybe realize that you need a different material for different parts. But looks like a really nice project.

I think you need to make many small decisions. Like how to print each part, orientation, material, color .... A really nice journey where you can learn a lot. Just keep your tests in mind and adjust your slicing strategy. MMU2 is just one tool. You have also molds, epoxy, coating and many other options to create each part exactly how it's needed.

RE: Just How Multi-Material Is The MMU2S?

@nikolai-r

As strong as if you were to print the part in single colour mode ;^) Hence the reason for this big test, I wanted to see just how viable the MMU2S is for printing 0mm interface supports. Turns out (for me at least) if I want to keep part strength then MMU2S  is a no go, instead I would need to find a printer with at least two hotends 

Thanks for that, everything you said definitely needs to be taken into consideration when printing. I am hoping to use 3D printed parts as much as possible but do realize that some will have to be machined (like the mechanism controlling the "firing pin"). Though so far the initial tests (printed in single colour) are quite promising:

https://www.antalife.com/2020/05/project-half-life-2-ar2-update-4.html

RE: Just How Multi-Material Is The MMU2S?

Posted by: @antalife

@igor

Thanks for sharing the pictures, very cool layer effect 😀

I think with a "large" model like that you don't need to worry about contamination between PLA & PETG, as like you said it's decorative. Contamination becomes an issue when the printed part is meant to hold some weight, for example a bracket/light-fixture/cable-holder...

Also I suspect if someone tried to pull the top/bottom of model apart (for what ever reason) the model would fail at the PLA/PETG interface, as these materials are not compatible (chemically wise) even when printed at a higher temperature 

You maybe omitted but I wrote about strenght.It was surprisingly good as my test models with ~90% PLA layers. When I reached "compromise" temperature, I got cracks not in PLA-PET contact area but somewhere in pure PLA area, also not between layers. I just printed cylinders from slicer, with hand picked filament change moments. When they cracked between layers, it was between materials also.

Of course melting PLA and PET together should be like trying to weld steel with copper. It may even look good but it's mechanically poor because of big crystals and water that forms during cooling process. Sometimes I do such welds for my experiments, so I tried the same with printer.

RE: Just How Multi-Material Is The MMU2S?

@igor

Righto, one last question from me then. Can you give a link to the PLA & PET you used?

RE: Just How Multi-Material Is The MMU2S?

All were Prusaments, purchased with printer.