with the multi-material module still some time away and rembering that even with a Prusa MK3S MMU style filament changer, mid-layer colour changes remaining very cumbersome; I was researching on alternatives for full coloured model FDM.
With small handheld inkjet printers (that use default mid-market ink catrtidges from Epson, HP or Canon) becoming popular and quite cheap, I had the idea of attaching one to the 3DP module, which would allow for colour printing on the surfaces just printed (or lasered, of course) in one go.
Most of these handheld inkjets can trigger simply by moving them across a surface with a continous speed, so programming them would mean an arming command via bluetooth, USB or wifi, and then the G Code to move them slowly over the target surface. If you only wanted to colour surfaces parallel to the print bed, this would be reasonably easy to accomplish.
It would get a lot more complicated but rewarding to print onto each layer (e.g. some brighter wood particle infused PLAs react well to inkjet ink) in a colour profile that if seen from the side make it look like the model was painted; this technology is already on the market since years but so far with a lot less build volume than the bigger two snapmaker 2s.
I understand getting Luban or any other slicer software to drive the inkjet printer like this is a big technological stretch, but considering the margins that vendors on the market are able to charge for printer’s ink I think there could be some commerical viability to this, especially if the catridges and/or an ink absorbing filament were custom made for snapmakers.
Hmm. Honestly I think it would be more of a question if it can print along the layers without running ink. There’s also the issue that this is bulky, I don’t know it’s weight but mechanically I think it would be more wear on the carriage slider if it’s too heavy, as it would be impossible to mount to the side of the head so it would have fulcrum (I think that’s the right word) leverage pulling on the slider because of how far it would be sticking out. I’m not a mechanical engineer though so I could be completely wrong.
It would have to be precisely in line with the nozzle, and it may end up blocking the vents on the front of the head, let alone the filament door, as that’s really the only place it could be mounted unless someone designs a mount bracket that lets it mount behind the head.
It would also increase print times dramatically, I think it would just be far too time consuming to actually be worth it when a paint brush and acrylic paint, or even air brush, can accomplish the same thing in most likely less time.
You mentioned ink absorbing filament. It would be a bad idea to run that through a nozzle I would think. It would also mean the filament is no longer dry, or dimensionally accurate. Ink has volume and that volume doesn’t just disappear when absorbed into filament. The filament would swell dimensionally a little bit, like a sponge does when absorbing liquid.
Like Artezio says, I think there are practical problems. In addition to the mechanical ones that have already been mentioned, the ink itself may be a problem: it isn’t intended to be added to molten plastic, probably hasn’t been tested for how it behaves above the boiling point of water, and may outgas toxic fumes or degrade the plastic, or just fade relatively quickly after the printing is complete. (Existing systems are probably very careful about what ink they use.) You’d need a specialized dedicated print head and well-tested consumables to make this work right, I think.
That being said, I can just barely see how you might assemble a one-colour external add-on system for the current print head that would do something like this. You’d need to use a narrow ink cartridge rather than a boxy one (I used to have an Epson multifunction that took flattish cartridges, 12mm x ~55mm x ~70mm) to reduce the mechanical problems, and mount it flat to the print head, then balance some kind of controller on top of the print head to drive it with. The controller would have to tap into the wiring. Might have some applications in producing faux wood grain that actually looks like cohesive tree rings and goes below the surface of the printed object. (Note: I am not an engineer.)
One more thing I’d like to add. Snapmaker’s multi-material module (henceforth MMM) is going to pretty much work the same way as the mosaic pallette. Mosaic Pallette 3 and the 3 Pro just came out and like the 2S it has already been confirmed by Mosaic to be compatible with the Snapmaker, both original and 2.0. It makes new multicolor filament on a single strand according to the gcode that you designate for colors in the slicer. The Mosaic Pallette itself is an extruder.
