New MMU system announced by Prusa  

Re: New MMU system announced by Prusa

From the one photo they published, it looks like the MMU 2.0 has a feed tube that moves between multiple input ports, with one stepper to feed and retract the filament, and another to move the feed tube between ports. From there it just goes right into the direct drive extruder.

There's a lot to be said for this new design. It gets rid of the multiplexer and all the problems that caused, it's easy to disengage and go back to a vanilla setup, it keeps your printer a direct drive setup, and it should be dirt-simple to scale up to more inputs if someone wants to design a version with 8, 12, or 20 input ports (setting aside the impracticality of actually printing with that many material changes in one print...).

My only yellow flag on this is whether it will require a functioning filament sensor to work properly. The MK3 optical filament sensors are problematic with a lot of glossy/transparent plastics, to the point where the sensor is now disabled by default. I'm hoping that either they don't rely on the sensor, or they've worked the kinks out by then.

Re: New MMU system announced by Prusa

So I guess this is the admission that MMU 1.0 was total crap? 😀 I wonder if they will still take back the unopened MMU 1.0 I have had sitting around for the last year as I try to make the other one work reliably.

Re: New MMU system announced by Prusa

It looks like this makes the printer a lot taller. Great improvement, don't get me wrong!

Can anyone give me an idea how much taller this will be than the MK2 MMU? I JUST got finished rebuilding my lack enclosure to fit the old MMU, lol! Most of the parts are easily modified, but the polycarbonate panels are not at all 🙁 I'm hopeful that the extra clearance I added (about 6 inches) will be enough to handle this upgrade. If not, is there any reason the base of the new MMU cannot be shortened a bit?

That being said, I love love love the direct drive. That will probably solve all of my issues with the current bowden setup! Great job there. It looks like this will add a bit of time to filament switching, no? I'm guessing it will be a bit longer than the current unload, minus the detract part? However, using waste to do infill would probably more than make up for that, depending on the situation.

Thanks!

Re: New MMU system announced by Prusa

It looks like this makes the printer a lot taller. Great improvement, don't get me wrong!

Can anyone give me an idea how much taller this will be than the MK2 MMU?

I doubt if even Prusa knows at this point what the final dimensions of the MMU 2.0 will be. The photo on the blog entry is a prototype, and they're still at least two months from shipping. So I would expect the design will change, possibly a lot.

Re: New MMU system announced by Prusa

Well I guess they realised there were some issues that needed resolving. I suppose that the only way forward is to have this backported to the mk2 printers and that you can "upgrade" to this system from your current MMU system.

Looking at the photo of the prototype, my guess is that an upgrade from MMU1 to MMU2 is likely to be pretty cheap. MMU2 uses three steppers rather than four, and you can probably reuse the bowden tubes from MMU1. Most of the rest of the parts look printed, so it may be that the only new hardware you would need to buy is a leadscrew.

So yeah, the way forward is probably to upgrade to MMU2, but it may be cheaper than you'd expect.

Re: New MMU system announced by Prusa

I'm pretty excited about this thing not being a bowden anymore. That is going to be awesome. My MMU works fine in terms of jamming and such but the stringing issues and limitations on soft filaments was destroying all my joy for printing.

Re: New MMU system announced by Prusa

This looks brilliant, I hope it's not another marketing stunt. If they go ahead and offer an upgrade for existing MMU users at reasonable price, I'll shut up and be a fanboy again. Looks to me like all you need is a filament sensor and (2?) leadscrew(s) (if they don't opt for motors with integrated screws but the shown printed parts could be easily adapted to use couplers). The rest would be printed parts and I guess tool changes are only GCODE (i.e. multiplexer board can be reused as well).
I hope they'll start selling the magnetic 12V hotbed and the filament sensor separately, the current upgrade paths don't make much sense for MMU users since you end up with lots of unneeded stuff. Best would be a "MK2s with MMU" to "MK2.5 with new MMU" package.

What I like about the idea is you can basically adapt it very easily to any printer that can run a direct drive. If your board can drive 3 extruders you're golden, for old-school RAMPS-like setups you could just switch to a Rumba. There are a lot less dependencies, fine-tuning and cost involved, and it will run without the bondtechs. The only things you would have to calibrate once are the transfer tube length and offset between filament ports.

The question remains why they didn't post a simple "We're aware of the problems and working on an entirely new solution which we will provide within X months at low cost to existing users".

Re: New MMU system announced by Prusa

Very excited to get details on the new system! If they post the plans I wouldn’t mind self sourcing all the materials. I’ve had my MK2 MMU to MK3 MMU upgrade preordered since it appeared in the shop. Unfortunately I have my doubts about it shipping in the timeframe mentioned, just due to PR’s track record. I wouldn’t be surprised to see it slip even into 2019...

Re: New MMU system announced by Prusa

Me neither. Indeed there wouldn't be much to source if they release the printed parts. I see a filament sensor (or two?), smooth rods, threaded rods and bearings. Apart from that only a Noctua fan (got one already).

Re: New MMU system announced by Prusa

I'm (also) very excited about the redesigned MMU. In particular, I love that it's (hybrid) direct drive, meaning that it'll work with flexible filaments better than a bowden setup (the original MMU) would, and my main interest in printing with multiple materials is the materials properties (rigid, flexible, dissolvable support) rather than colors. Though of course multiple colors is fun, too!

And I think I saw a note about Cura being able to use infill for purging filament, which feels much more efficient than an external tower, since you need infill, and don't need a tower. And in addition to saving material, it'll save time!

So very excited for when the MMU 2.0 arrives.

Re: New MMU system announced by Prusa

Has someone figured how this new system works? I have been looking at the picture but still cant figure out how the switch between the different filaments?

Re: New MMU system announced by Prusa

I'm (also) very excited about the redesigned MMU. In particular, I love that it's (hybrid) direct drive, meaning that it'll work with flexible filaments better than a bowden setup (the original MMU) would, and my main interest in printing with multiple materials is the materials properties (rigid, flexible, dissolvable support) rather than colors. Though of course multiple colors is fun, too!

And I think I saw a note about Cura being able to use infill for purging filament, which feels much more efficient than an external tower, since you need infill, and don't need a tower. And in addition to saving material, it'll save time!

So very excited for when the MMU 2.0 arrives.

I am excited about the ability to print with flex too. The only reason I didn't by the last one is you lost the ability to print flex and also the amount of waste material Hopefully they lesson the waste material

Re: New MMU system announced by Prusa

Well, obviously the unused filament is parked behind the frame. In front you can see a carriage that propagates the used filament to the feeder gear in the print head. The second motor must somehow drive the input side selectively (we don't see the back so no idea how it works). My guess is theres a gear for each filament coupled to a smooth rod, which is somehow engaged by the carriage travelling in the front.

Re: New MMU system announced by Prusa

Can you mount spools above the frame.. Would it still be able to feed correctly ?

Re: New MMU system announced by Prusa

Well, obviously the unused filament is parked behind the frame. In front you can see a carriage that propagates the used filament to the feeder gear in the print head. The second motor must somehow drive the input side selectively (we don't see the back so no idea how it works). My guess is theres a gear for each filament coupled to a smooth rod, which is somehow engaged by the carriage travelling in the front.

about the 2:42 mark
This was the version before using the PINDA as the filament sensor