Unfortunately, Marlin supports additional extruders in a fixed way. Hopefully we won’t make the same mistakes in the firmware for the new generation of ARM-based boards.
Would it be possible to use a single inkjet nozzle to just color the filament after deposition? Use a solvent based ink that will evaporate soon after it hits the plastic and you should be done. I like these nozzle ideas a lot but I wonder for coloring purposes if there is a better way.
@Stephen_Jensen ive also thought of that, but have been unable to test. If you printed in white abs, carried around a cmyk ink jet print head, you could print a layer, then go around the border in full color. Most inks are acetone based so it would fuse with the filament quite readily. I was very interested in the ink shield for this purpose but I haven’t seen any further development with it. :-[
I wonder if you could just use a solvent based ink then. I know poster printers often use them but they are a little bulky for our purposes. The marker idea would certainly build on previous demonstrations that they can do a good job dying filament but I don’t know how scalable they are for many colors compared to a nozzle.
Most inkjet inks are water+ alcohol. Solvent based inks are only found in commercial high volume printers, and the heads are very expensive.
While thinking of printing acetone-based ink onto a just-printed layer, remember that the layer is still hot. To get proper adhesion between ABS layers, the top layer should still be heated above the boiling point of acetone, otherwise you get a weak bond and delamination in the middle of the print. Printing acetone onto the still-hot layer will cause it to immediately boil, and will significantly cool the plastic in the process (if you’ve ever spilled a little acetone on your finger, you know it’s evaporative cooling can be quite effective). Even if the acetone did have time to soak into the layer before it boiled, it would create unsightly bubbles/cavitation in the plastic when it did boil. Try hitting an acetone-treated print or an acetone-dipped piece of filament with a heat gun before the acetone has had time to fully evaporate out (which can take days) to see what I mean.
But acetone isn’t a solvent for PLA, so would acetone-based ink really work any better than the alcohol/water-based stuff?
So I looked up that 1 HP printer cartridge of 17 mL ink prints on 391 pages of paper. That’s 0.44 mL/page and a page is like 603225 mm2 so when you calculate that out it is like 0.73 nanoliters/mm2 but since the estimate for the number of pages assumes say 10% coverage that means that you actually use 7.3 nanoliters ink/mm2 on paper. I bet you will need more on plastic but is still not a huge amount of ink. Granted you are only depositing on a small volume of plastic too but I just wanted to throw out some numbers. The delaminating problem is a good thing to keep in mind. Maybe nylon would be better since Richrap said you can use water based inks. I got the sense that bot objects was doing something similar but since they might be vaporware I wouldn’t put a lot of stock in it: http://botobjects.com/latest-updates
Use dichloromethane ink instead!
But in all seriousness. E3D is willing to fund or put a bounty on that fourth extruder support.
Can anyone point me in the right direction so we can support the developers (financially or with hardware, or a mixture of both) so that the community can get a 4th extruder available in marlin?
(Sorry Sanjay to hijack the thread, good luck a 4th extruder would be awesome too!)
@Sanjay_Mortimer Considered talking directly to Ultimaker? Other than that there’s a guy on the Reprap forums called Lajos who seems to know his stuff - I’ve PM’d him to see if he’s interested.
“directly to ultimaker” means it would likely be pushed to @Daid_Braam . Maybe he has some input on this?
Right now Marlin supports up to 3 extruders. Adding more would simply be some code duplication, not impossible, just requires some hacking. (I’ve already hacked up Marlin to support 4 temperature sensors a while back for a different project. But there was no stepper control in there).
I currently do not know of any board with more then 3 extruder motor outputs. (RUMBA board has 3) If you are looking to save pins on the controller, you could put the extruders on a single DIR/ENABLE pin, and only differ in the STEP pins. As Marlin supports only 1 extruder at the same time. Anyhow, if you manage to build hardware to support more extruders, hacking up Marlin would be trivial.
@Jelle_Boomstra unless you can formulate a solvent ink with a boiling point and a specific heat similar to water+ alcohol that the inkjet was designed for, all you’ll get is a burned out printhead in about 3 seconds flat. Thermal heads like hp are extremely sensitive to changes in ink formulation. If the fluid is too “thin” (low boiling point) the head will vapor lock and burn out for lack of coolant. If the fluid is too thick it won’t jet.
You might have fewer problems using a printhead based on piezoelectric drivers instead of thermal. That’s what all the commercial printheads use, because it’s more reliable/ longer life than thermal. I’m pretty sure there are some consumer piezoelectric inkjet heads out there.
Why not use color toner for laser printers?
These are posts from 2013 that was copied over from Google+ (see gplus mark). You probably wont get any answer here.