Meet U.S. patent 5,121,329, which covers fused deposition modeling–the most popular form of 3D printing. Its filing in 1989 coincided with the founding of Stratasys, which today is one of the most powerful 3D printer companies in the world. But the patent’s biggest impact came in 2009, when its expiration opened the floodgates for a wave of increasingly cheap desktop 3D printers that are now available to consumers.
A similar wave of stereolithographic printers has popped up this year as more and more patents for the technology, which uses a laser to cure liquid resin layer by layer, expire. Patents have also begun to expire for selective laser sintering 3D printing, which uses a laser to seal powder together into a 3D object.
Quartz’s Christopher Mims suggested last year that key patent expirations in the first half of 2014 would bring a huge surge of interest in SLS printing. After all, it is commonly used to 3D print in metal, which is currently impossible on an FDM or SLA printer (though there are some primitive workarounds, and we may be on the verge of SLA metal printing). A desktop SLS printer would allow consumers to move beyond plastic trinkets and into metal jewelry, tools and even, gasp, guns.
But that explosion of SLS printers has not come. FDM still dominates the desktop printer space. What gives?
The answer is that SLS printers are inherently dangerous, messy and just plain difficult to engineer. While the laser in an SLA printer is comparable to one in a Blu-ray player, an SLS laser is powerful enough to be dangerous to any human who comes in contact with it. And the design of an SLS printer generally involves pistons, rollers and gas chambers, making it much more complicated than the basic FDM printers hobbyists have been building for a decade now.
As MakerBot CEO Bre Pettis said to me in October: “There’s things that happen when metal melts. Aluminum you [melt] around 700 degrees. Does your oven go up to 700 degrees? You probably don’t want that in your house.”
Afinia vice president John Westrum echoed Pettis, noting that not only is the laser very powerful, but it is also not nearly as easy to procure as the laser that goes into SLA machines (which is generally exactly the same as those found in overhead projectors).
But that has not stopped hobbyists from trying. MetalBot, SLS Wax Printer and OpenSLS are all open-source projects available to anyone interested in creating their own SLS printer. Andreas Bastian, creator of OpenSLS, is now working on another project that involves converting laser cutters into SLS printers. Laser cutters are relatively common and inexpensive and use a laser that is similar in power to SLS printers.
While his project could make SLS printers more accessible for offices as well as grittier, more experienced spaces like hackerspaces, he doubts that a consumer-friendly SLS printer is around the corner.
“As more minds start working on the problem, I think there will be significant breakthroughs on the materials side,” Bastian said. “I don’t personally think they’ll show up in homes or garages anytime soon. SLS is a much much harder and more expensive process than either SLA or FDM. There are some really serious material handling challenges and safety concerns.”
What will undoubtedly happen is that the price of professional SLS machine options will drop dramatically.
“The only reason it’s a million dollar machine right now is it has been such a locked-down space,” Bastian said. “If we look at the last 7 years in FDM, I would almost argue that the capability of the machines has not changed. I think the main differences has been in cost. There has finally been some competition to optimize these machines for some degree for other markets, but also for material consumption.”