Inkjet-based 3D printing resources

[en.wikipedia.org]
[home.howstuffworks.com]

*Fabrication using Ink Jet Printing : overview
[www.efunda.com]

*'Inkjet Applications' by Matt Gilliland
[www.amazon.com]
[www.mattgilliland.com]

**The associated kits
[parallax.com]
[parallax.com]

*The Piezoelectric Oligonucleotide Synthesizer And Microarrayer
GPL driver board and software to control an inkjet-head robot that prints
"customizeable DNA microarrays":
[www.bioinformatics.org]
Seems to have full documentation, lots of information.
via
[techbuffet.wordpress.com]

*fab@home: Evan Malone is working on this as well:
[fabathome.org]

*"Graham Stabler" and the CAD_CAM_EDM_DRO group's tinkering:
[www.indoor.flyer.co.uk]
[groups.yahoo.com]

*Interesting application
[people.clemson.edu]

*Bit of discussion.
[www.cnczone.com]
(mentions "I used HP stuff because I had it in a surplus pile. HP thermal
inkjets should not be used to dispense flammable liquids. I would use
an Epson piezo print head if I needed to dispense anything that wasn't
water based.")
**Note, Hazard: spraying a fine hot mist of thermoplastic, wax, or
flammable liquid may start a fire.

*Jeremy Risner's work on flextronics:
[www.cs.berkeley.edu]
[www.cs.berkeley.edu]
mentions 'piezo printheads from MicroFab, Inc.'

[www.microfab.com]
They sell them, along with individual (in-house fabricated) print heads. 'For customers interested in developing their own system using MicroFab components and subsystems,'

Edited 3 time(s). Last edit at 12/13/2007 09:38AM by SebastienBailard.

Hmmmm, inkjet!

That's the perfect technology for my UV-setting resins!
What is the viscosity needed for the ink?
Also, won't it clog easely with resins?
AFAIK, it's based on microbubbles generated by explosive evaporation...
Thats the kind of thing that could cause a monomer to polymerize in the inkjets canules.

There are two kinds, piezoelectric and thermo.
*Piezoelectric uses a piezoelectric element to mechanically push the droplets out.
*Thermo heats up a resistor. The heat creates a steam bubble in the (usually aqueous with thermo) ink, and that bubble pushes the droplet out.
See:
[home.howstuffworks.com]

I've been thinking and this might be the ideal technique to use the "spray-on" catalyzer on top of a layer of liquid resin.

Imagine a surface of resin in a vat that is being filled a layer at a time. after thi sfilling step, the inkjet sprays catalyzer on specific points, initiating the polymerization. neigbouring points would merge together. Newly sprayed points on top of the previous layer would have to grow enough to merge with previous dots in the layer below. If the layer below was not polymerized, the uncured resin would serve as support material for the top layer.

The shape of one of these points would likely be a bead, kid of lenticular. Question is, how deep would an inkjet spray penetrate inside the layer? it would create a microsopic crater that would be filled back after impact. This would generate turbulence enough to encourage mixing. in that spot.

I'm thinking out aloud here....

SebastienBailard Wrote:
-------------------------------------------------------
> There are two kinds, piezoelectric and thermo.
> *Piezoelectric uses a piezoelectric element to
> mechanically push the droplets out.
> *Thermo heats up a resistor. The heat creates a
> steam bubble in the (usually aqueous with thermo)
> ink, and that bubble pushes the droplet out.
> See:
> [home.howstuffworks.com]


Brilliant!

The piezzo-electric one seems a safer bet for resins as it wouldn't initiate any cheical reaction iside the delicate ink-jet parts.

I found this, via google "viscosity inkjet"
'Rheological Characterisation of Inkjet Fluids'
[www.cheng.cam.ac.uk]
It looks like ~ 30 mPa s, but I'm not sure if that is the same stuff as real inkjet ink.

Looking at microfab's inkjet-type print heads:
[www.microfab.com]
"Fluids with viscosity less than 20 cp and surface tension in the range 20-70 dynes/cm can be dispensed." -This goes for both their high-temperature and low-temperature inkjet-type heads.

Regarding UV and 3D printing, you may already know about this:
[home.att.net]

Your idea seems plausible; I was concerned about the remainder of the liquid resin which was not catalyzed, but that can just be reused, I imagine.

... here you can find some nice hacks for salvaged ink-jets: [www.hack247.co.uk]

And for the basics and building on my own i got the book "Inkjet Applications" by Matt Gilliland: [www.amazon.com]
- here i have the complete specs, needed electronics and programming samples for the HP51604A/5R/5B ink-jet-cartridges ...

I think using this infos to make some experiments with SIS-fabbing (=Selective Inhibition Sintering), where i simply print the contour-outlines and separation-lines with salt-water on the powder-surface (where the salt crystalize between the powder-particles) and when melting the surface with an IR-heater (quartz-tube from a toaster) the salt separate the melting zones in the slices ...

@Fernando, when printing small droplets on powder you didn't have much mixing or impact-craters - the ink only cover the surface of the top-layer without much moving. The droplets are in the sizes of 30 to 80 microns, so there isn't much inertia.

You have to select the right liquid for the actual powder, or it wouldn't wet deep enough or it would wet to much and make 'fuzzy' outlines ...

Viktor

I wonder; could one make a slurry of powdered bronze and monomer, squirt catalyst on the surface to make a hardened slice of the object, put down another thin layer of slurry, another squirt, and so on?

Remove the object, pack it in aluminum oxide, refractory investment, or ceramic shell, and then fire it in a vacuum or reducing furnace, and voila: a nice bronze object. (I'll develop this part of the idea in another thread).
EDIT: [forums.reprap.org]


There's also the powdered bronze bed and inkjet of cyanoacrylate approach.

Edited 1 time(s). Last edit at 12/17/2007 03:29PM by SebastienBailard.

SebastienBailard Wrote:
-------------------------------------------------------
> I wonder; could one make a slurry of powdered
> bronze and monomer, squirt catalyst on the surface
> to make a hardened slice of the object, put down
> another thin layer of slurry, another squirt, and
> so on?
>
>
>

Definitley a good idea, yes!
The only requisite here would be that the timing of polymerization is accurate enough so as to permit interlayer adhesion. Maybe this could be achieved with incomplete hardening during the printing process under room-temperatures. Then, Once the object is finished printing one would bake the object for an hour or so in an oven at 50 or 60

Instead of inkjet, what about the same principle behind laser printers. Electrostatic printing. I just thought that since toner in plasic, why not have just layer upon layer of toner be placed on top of each other(With some medium to hold it in place of course). The end result before the baking process would look like a stack of paper, afterwords, a plastic part in a pile of sand.

---

Jay

I had a thought about this style of 3D printing. What if the the print medium was water soluble? Could you used the layered electrostatic print mechanism on something like rice-paper, then when your object has been printed you could bathe the entire thing in luke warm water untill the rice paper dissolves, leaving you with, hopefully, your 3d object?

I have no background in this kind of science, I'm just thinking out loud really. But is it feasable?