Prusia i3 Mk3 Multi Material @ MRRF 2018  

Re: Prusia i3 Mk3 Multi Material @ MRRF 2018

People say that the waste is "just a little filament". But if you price that over time, the life of the printer and you could buy two printers, MMU units or maybe worth the upgrade to a dual extruder /tool changer. Then you add the fact that some people have more than one printer so multiply the loss.
All I can say is that I would buy it.

Re: Prusia i3 Mk3 Multi Material @ MRRF 2018

Let's hope PR listens to you. I don't realistically see me buying a UM3 or UM5S - just for fun.
On the other hand, I don't see the MMU1/2 concept work for PVA/BVOH with a realistically sized print.
From what I've seen now, the MMU seems more a "proof of concept" for multi material print than being of any realistic use, particularly with expensive soluble support material.

- Martin

it's possible to do IDEX but current machine is bit small on the X. needs extra room to park extruders. but it's just two X motors instead of one unless you do some fancy switching thing and two extruders with room to park them off the heatbed if you want full volume printing. no tower, no waste. (except to build pressure back up i guess, which is minimal)

Re: Prusia i3 Mk3 Multi Material @ MRRF 2018

People say that the waste is "just a little filament". But if you price that over time, the life of the printer and you could buy two printers, MMU units or maybe worth the upgrade to a dual extruder /tool changer. Then you add the fact that some people have more than one printer so multiply the loss.
All I can say is that I would buy it.

The ability to use infill for purging should help quite a bit. That is, they realized that the color of the interior of most prints doesn't matter, so you can use that to purge plastic on color changes. So if the cross section of the infill is enough to use up all of the purged plastic, you wouldn't need a purge tower. Of course, there's likely to be a purge tower needed at some point (e.g. when the cross section is small) but even so, the purge tower could be smaller than otherwise.

The other way to not waste plastic is to print a 'sacrificial' object, which is an object where color doesn't matter. The software will use that object for purging, so instead of a purge tower to throw away, you end up with something useful (but oddly colored) printed.

Something occurred to me: when using infill for purging, if it's not enough cross section to use the purge material at the configured percentage, perhaps it would make sense to increase the infill percentage to consume the purged plastic, so that instead of having a purge tower to throw away you'd have a stronger/denser object printed. Hmm.

Re: Prusia i3 Mk3 Multi Material @ MRRF 2018

If there are any colour changes on the top layer, there is no infill to purge into, so you would need a purge tower as tall as the object being printed, or a sacrificial object with sufficient top layer surface to accept the top layer purge material.
if there are any colour changes on the bottom layer, there is no infill to purge into either! so purge tower or sufficiently large sacrificial object needed there too.
I usually manage to make most of my colour changes in the first millimeter or so... to minimise purge waste... but I tend to print items with most colour detail at the bottom...
regards Joan