Is there a UK second hand market for MMU2?
I purchased the multi-material Unit for my schools 3D printer a while back and this weekend finally had the time to build and install it, given it's reputation it seemed to go very smoothly and the first layer calibration print worked perfectly.
Right until it needed to retract the filament, which it stopped doing halfway up the tube between the MMU and the extruder, from that point things have gone from bad to worse.
I've followed all the guidance and every online tutorial I can find and nothing seems to make it work, reflashed both sides several times and lost count of the number of times I've released and unreleased the top of the MMU.
It will now 'bite' the filament and pull it forward onto the gears but will move no further forward on either of the two channels I am experimenting with, if pushed through to the other side with gentle pressure it will not retract.
With this glowing advertisement, I am wondering if there is a market for selling these on? I clearly lack the level of skill or luck needed to get this working.
Given how amazing the MK3S have been I am really disappointed by this unit.
Rather at my wits end at this point as it gives no meaningful feedback other than MMU needs attention.
RE: Is there a UK second hand market for MMU2?
To answer the title question: You won't get much money for a 'failed project' as purchasors have no idea why it went wrong so even the spare parts value is reduced, especially if you've eaten all the gummy bears.
I have an MMU which I am cannabalising for spare parts not because it failed but because it didn't do what I wanted. It's not too hard to get the MMU to print multiple colors of the same filament, it's a matter of getting all the settings very finely tuned and arranging the spools so there is minimal drag/friction then babysitting the early prints until everything is running smoothly. However printing different filaments with the inherent temperature changes and the annoying risk that the wipe tower, where the filaments are mixed, will fail and take the print with it, is fraught with problems.
I don't consider the MMU to be suitable for use in mainstream schools.
For teaching purposes search for threads on here about 'manual MMU' which take you through the process of generating code in which you can make changes in the first two layers then let the rest of the print run on in a single filament. This allows you to make parts with simple labels with the machine attendance and filament swapping all concentrated at the start of the print after which you can leave the printer to run, unattended, to completion.
You can do this with or without the MMU. If you leave the MMU fitted you will repeatedly be pestered to attempt ambitious prints that are bound to fail in a school environment so I suggest removing it and using some of the parts in (say) a robotics project ensuring there's easy no way back.
Hth, Cheerio,
RE: Is there a UK second hand market for MMU2?
@diem
Thanks for the pointers, I had wondered with an 8 week lead time if there was a market but what you say makes sense.
I had an idea for a simple pixel-based project that the MMU should have been perfect for, but agree it may be time to just write off this one as a bad venture.
The Prusa printers have been absolute workhorses for use in school, over 1000 hours on each with no significant issues once they were built, a shame the MMU is not quite so user friendly.
RE: Is there a UK second hand market for MMU2?
You can do this sort of thing without the MMU:
A left handed scale that's quite hard to source otherwise.
For a wide range of practical projects this level of multicolour printing is enough.
Cheerio,