3-D Printing - what substances can be used to build up the "image"?

3-D printing is getting a lot of airtime and hype lately and I have to admit it does sound promising (I heartily recommend the article on 3-D printing which appeared in The Economist Feb 12, 2011 if you can access it).

My question is regarding the nature of the substances that can be used to build up the image. The Economist article mentioned titanium powder, “plastics”, and concrete (I assume as a powder). The Wikipedia article talks about plaster and resins, and the beautiful process of 2-photon photopolymerization but without mentioning the nature of the polymer in the latter.

What other agents are available? What’s down the pipes? (Any miscellaneous and sundry points about 3-D printing are also welcomed)


There is a 3D print-on-demand site called Shapeways that prints in a variety of materials. Here is their materials page–you can click on each one for more information. This probably isn’t an exhaustive list of all the possibilities, but they have a lot of options:

When I first read about this, about 20 years ago, they mentioned a polymer plastic that could be polymerized (turned solid through molecular chainin) when hit by a particular wavelength of light. The “printer” started by paining a crosssection of the bas of the object onto a barely submerged platform. AS th platform is gradually lowered, each succesive layer of teh corssection is painted with the laser, thus building a solid object in a vat of the unpolymerized fluid. When you’re done, pull it out and drain off. This would get you a prototype shape to verify your designs, but pobably not durable enough for what you need.

No clue on what the fuild was, except i’s some organic compound that polymerizes when exposed to light (or was the laser providing heat?).

I spent five years working for a company that made 3D printing systems for metal. Basically it was computer controlled laser welding in an inert atmosphere. Due to thermal issues, tolerances were not tight, and since it was built in layers of weld bead, surface finish was inferior to all but the crudest of castings. In the metals we did well, we could get strength better, and and porosity lower than wrought. We did Titanium, some tool steels, and some stainless pretty well. Aluminum was a very tough nut to crack. It reflected the laser, so it was hard to get the heat in, and what heat you did get in got sucked away at a high rate due to high thermal conductivity. We had some tricks that helped, but results were still not great.

The systems were fairly fussy. We used metal powder as a filler, which is tricky to feed at a well controlled rate, and tends to abrade, jam, and clog things you’d rather it didn’t. The inert atmosphere was inside a glove box, and there were always issues with leaks, Argon Dewars feeding liquid and sticking the regulators, etc. etc. Add in the problems of care and feeding of a 500-2000 watt laser and it was lots of fun keeping the things going. High purity, consistent grain sized metal powder is frighteningly expensive stuff also. Considering cost of the systems, cost of consumables, cost of power, cost of labor, slow rate of deposition, and mediocre dimensional control, you ended up with very expensive widgets. Basically it was only worth it if there was no other way to produce the parts.

We had a few commercial customers, and the rest were either DOD funded folks or University researchers. Probably the only one using one of our systems and making it pay for itself is a high end welding shop doing repair work for the Mining industry and also maybe (would be after I left) the aerospace industry. There was one guy making special parts for racing engines, but racing is mostly a money pit that turns advertising dollars into noise, burned rubber, and bent metal.

There are many different technologies used for 3D printing now, with tradeoffs depending on the speed of printing, required resolution, strength of material, and such. The UV-curable resin was one of the earlier methods. It’s still used fairly often today, being fairly fast and high-resolution, but the resin is expensive. Other methods in use today involve selectively sintering together objects from very fine layers of powder, which is slower than the early UV-based methods but gives you a lot more variety in materials you can work with. Then there’s the extrusion method used by Makerbots and other hobby-grade 3D printers, where a fine filament of plastic is pressed through a heated nozzle to create a 3D object one line at a time. That’s very slow, and restricts you to working with a few types of plastic, but the printers and the print material are quite cheap.

Wow, crazy as it sounds, I think I know exactly who you’re talking about. I just visited their shop a couple months ago, because they’re building some of those aerospace-related pieces as a supplier to a big defense contractor I babysit.

Was I at the right place if the owner took us on a field trip to Mt. Rushmore when we were done?


Human tissue.

I had no idea. Very impressive.

Isn’t it? I so want to get my hands on one of those machines.

Makerbot kits are down to about $1300 these days. That’s still not quite cheap enough for me to be able to justify buying one, but it’s getting close.

I’ve been pondering the possibility of a 3D printer using paper. On each sheet, you would “print” using a plotter with a sharp stylus to perforate the outline, and put down a thin layer of heat-activated adhesive. Then stack all the sheets together in a neat ream, heat it to activate the adhesive, and then separate off the perforated negative space.

Sounds like a job for my friend’s CriCut. It accepts vector artwork and cuts along the lines. You just need something to turn your 3D model into a bunch of contours.

:smack: My sister has one of those-- I really ought to have remembered that it actually exists. It just might actually be possible to build an off-the-shelf 3D printer, after all.

It’s been done: http://www.mcortechnologies.com/

For the sintered plastics, I think nylon is a type used.

Great link by the way. (Pricey stuff!)

Heh, thats the guy. Company is his initials. I got to go to Mt. Rushmore also. It was much appreciated as I only found out my driver’s license had expired when I went to the airline check-in, so I was unable to rent a car and was having to take cabs and bum rides.

Not to hijack the thread, but I was wondering if anyone thinks 3D printers will ever drop in price to the point where they’ll be affordable for everyone, the way laser printers now are. If so, how long? 5 years? 10 years? When do you think, if ever, 3D printers (assume an inexpensive material, some sort of plastic, being the standard printing material) will be basic components of home PCs? When will I be able to buy a good 3D printer for $299.99 at best buy, along with refill material for $20-40 a pop? Obviously the size of the things it can make would affect the price and complexity… assume a 3D printer that can make something up to a cubic foot or so (plus or minus a few inches) in size.


Check out http://reprap.org it is an open source project and you can make a printer for about $500 that will outprint the makerbot.

I have just recently made my 3rd version and now am mostly limited by my CAD skills, and print time.

I’d thumbsuck around 10 years to get a reasonable (sub-$500) off the shelf printer that prints in ABS (same material as Lego)

If you’re willing to make it yourself, like rat says, you can have that now. Of course, there’s a difference between $500 and $300, but think what laser/inkjet printers cost when they came out.