Low-cost 3D Printing From Desktop Factory

If you've struggled in vain to get your manager to sign off on a 3D printer for your engineering team, don't give up just yet. Desktop Factory, an Idealab start-up company, has come up with a system that costs just under $5,000. And in time, the system may cost far less. "Our intention is to bring the price down to $995 by 2011," says Cathy Lewis, Desktop Factory's CEO.

With a housing that measures just 20 x 20 x 25 inches and a weight of 90 lb, the system lives up to its "desktop" moniker. "It's not much bigger than the early laser document printers," Lewis points out. "It really is a desktop machine sized for use in spaces as small as an office cubicle."  The system builds models up to 5 x 5 x 5 inches.

Desktop Factory's 3D printing system works very differently from the 3D printers that have gone before it. "The idea was to move away from lasers and binding agents and build a new, less costly process from the ground up," says Lewis.

To that end, the Desktop Factory system builds models layer by layer using what in essence is a drum printing technique. The system first lays down a thin (17 mil) layer of thermoplastic powder on a rotating drum. A halogen light focused to a tight beam then selectively melts and fuses that powder–with the fused region corresponding to a slice of the model's CAD geometry.  Once the layer is melted, the machine transferred to an build platform, which presses the accumulated layers against an annealing platen as the build process proceeds. Each individual layer has a thickness of 0.010 inches.

The Desktop Factory's build material is also unusual prototyping industry. The company starts with a nylon-12 base resin, which in itself is hardly exotic. But Lewis points out that the company adds aluminum and spherical glass reinforcements, creating a thermoplastic composite. The proprietary material also contains what Lewis describes as a "darkening agent" that allows it to absorb heat more effectively during the build.  

Getting this build material material to hang together in cohesive models requires some careful temperature control on the machine. Lewis explains that the system's halogen light source–which has three beam-size settings to meet different build speed and accuracy needs–fuses the build material at about 180 C. That's roughly five degrees above the nylon-based build material's melt temperature. The annealing platform is heated to about 170 C, just below the melt temperature.

With the Desktop Factory not set to start shipping until later this year, it's a still little early to get full picture of the system's capabilities. Lewis does say that the system is repeatable within one percent in the x and y axes and two percent in the z axis. She lists the minimum feature size at 0.040-inches. The company does not yet have any data about the tensile properties, though Lewis says she will share that information once the testing has taken place. Lewis says the company has a model cost target of $1/in³ of finished part volume. As for surface finish, the parts do require some sanding if cosmetics are important.

Desktop Factory has already sold 277 machines in advance of shipping any machines, and the company is holding off on taking more orders for now. "The response has been overwhelming," Lewis says. As prices for 3D printers start to fall, Lewis believes more and more individual engineers, designers and engineering students will be able to take advantage of three-dimensional printing. Over time, she says, there may even be a market for these machines in the home–for example, instantly fabricating replacement plastic parts for a cell phone or custom toys for children (check out this New York Times article about 3D printing's potential in the home).