By Gary S. Vasilash, Editorial Director

While there is on ongoing development of various polymers, metal powders, and related materials for additive prototyping equipment, there is one that is rather remarkable in its overall simplicity.

Arguably — assuming that you’re reading this in the physical magazine and not on the Time Compression website — you’re holding the material in your hands right now.

It’s paper. That’s right. When you hear people talk about “3D desktop printing,” when it comes to the machine from an Irish company, Mcor Technologies (mcortechnologies.com), it really is just like, well, desktop printing, except that what comes out is a model, not just images or words on paper.

Some people may recall that a variation of this technology was available some years ago. Back then, it was a company named Helisys and it was promoting its “laminated object manufacturing (LOM).” (This tech is now supported by Cubic Technologies:cubictechnologies.com) Rather than typing paper, it actually used paper that is more akin to what you would find in a butcher’s shop. And rather than objects that are generally desk printer sized — the build size of the objects that can be made with the Matrix 300 machine is 277 x 190 x 150 mm (10.9 x 7.48 x 5.9 in.), although pieces can be glued together to create a larger final end product — most of the LOM models I’d seen were significantly larger than a desktop.

The Mcor machine uses paper. Standard bond A4 paper. In the U.S., that’s not the standard size. But it is a standard in Europe. In fact, it isn’t merely the sort of “standard” in the context of “regular,” but “standard” in terms of the ISO 216 standard, which is based on the German DIN 476 paper size standards (there is a series of A-sized paper, starting with A0, and with A4 being the most commonly used paper size). And not only does a sheet of A4 paper measure 210 x 297 mm (or 8.3 x 11.7 in.), but it also has a particular mass: 80 grams/m2.

So one could argue that we’re really talking about not just “paper,” but a truly engineered material here.

That said, according to Mcor, the price of producing models with what they’re calling “Paper Rapid Prototyping” is 50 times less expensive than its nearest competitors. While there could be some quibbling about that, check out the price of a ream (500 sheets) of paper at Office Depot (officedepot.com) or Office Max (officemax.com) and it is clear that at least the raw material is economical.

The Matrix 300 machine, which is available in the U.K. and Ireland for 29,950 euro, is not expected to launch in the U.S. until the second half of 2010. According to a Mcor spokeswoman, while a U.S. price hasn’t been set, “It will probably be about $20,000.” (Mcor machines are being manufactured for it by Benchmark Electronics (bench.com), which has operations in 10 countries, including Ireland.)

So you have the machine — which measures a compact 950 x 700 x 800 mm but weighs 160 kg (350 lb) so the table needs to be sturdy — and the paper. But there is, of course, more. For example, there is the software needed to design the parts. Mcor has a partnership with CADspan, and is offering a a six-month free subscription to the company’s CADspan Pro with the Matrix 300 machine. When the partnership was announced in October, 2009, Charles Overy, managing director of CADspan (cadspan.com), said, “CADspan provides Mcor users a simple way to successfully 3D print a wide variety of CAD content including models from Google SketchUp and Google SketchUp 3D Warehouse.” Again, note that the use of the Google products drives down the cost of the overall process.

But for non-Google users, know that the system accommodates solid models from STI files that are then processed with its propriety software, SliceIT, which features 3D viewing, parts placement, orientation, and scaling.

And there are two other key elements. One is a water-based polyvinyl acetate (PVA) adhesive, or what is essentially plain old white glue that you’ve probably used yourself or with your kids on school projects. The other is a tungsten-carbide cutting blade that is fitted into a swiveling cutting head.

So the paper is fed, cut, glued, repeat. The glue location is based on what is called the “Eco-Physualiser,” which is said to permit selective location of the adhesive. Paper colors can be varied to provide built-in coloring of the object. When the process is complete, the result is, well, what appears to be a block of paper. Then there is a “weeding” process, which simply means peeling away the surround material (which acts as a support during the build process). The scrap paper can be recycled, in keeping with the “eco friendliness” touted by Mcor.

The parts produced have a resolution of 0.1 mm (which happens to be the thickness of the paper).