Rice University researchers have modified a commercial-grade CO2 laser cutter to create OpenSLS, an open source SLS platform.
Engineers at Rice University have modified a commercial-grade CO2 laser cutter to create OpenSLS — an open source, selective laser sintering platform that can print complicated 3D objects from powdered plastics and biomaterials.
As impressive as that may be, what really sets this system apart is its cost. OpenSLS can be built for under $10,000, compared to other SLS platforms typically priced in the ballpark of $400,000 and up. (That’s at least 40 times less than its commercial counterparts.) To make this a reality, this DIY device is equipped with low-cost hardware and electronics, including Arduino and RAMBo boards. The Rice team provides more detail around specs and performance in PLOS ONE.
“SLS technology is perfect for creating some of the complex shapes we use in our work, like the vascular networks of the liver and other organs,” explains Jordan Miller, an assistant professor of bioengineering and the study’s co-author. He adds that commercial SLS machines generally don’t allow users to fabricate objects with their own powdered materials, which is something that’s particularly important for researchers who want to experiment with biomaterials for regenerative medicine and other biomedical applications.
To test their concept, the team demonstrated that OpenSLS is capable of printing a series of intricate objects from both nylon powder — a commonly used material for high-resolution 3-D sintering — and from PCL, a nontoxic polymer that’s typically used to make templates for studies on engineered bone.
It should be noted, however, that OpenSLS works differently than most traditional desktop 3D printers, which create objects by extruding melted plastic through a nozzle as they trace out two-dimensional patterns and 3D objects are then built up from successive 2D layers. On the contrary, an SLS laser shines down onto a flat bed of plastic powder. Wherever the laser touches powder, it melts or sinters the powder at the laser’s focal point to form a small volume of solid material. By tracing the laser in 2D, the printer can fabricate a single layer of the final part. After each layer is complete, a new one is laid down and the laser is reactivated to trace the next layer.
The best way to think of this process, says Miller, is to think of “finishing a creme brulee, when a chef sprinkles out a layer of powdered sugar and then heats the surface with a torch to melt powder grains together and form a solid layer. Here, we have powdered biomaterials, and our heat source is a focused laser beam.”
The professor, who happens to be an active participant in the burgeoning Maker Movement, first identified commercial CO2 laser cutters as prime candidates for a low-cost, versatile SLS machine three years ago. According to Miller, that’s because the cutter’s laser already possessed the right wavelength and perfectly suitable hardware for controlling power and its axes with precision.
[Images: Rice University]