Open-Source 3-D Printing

Bioengineering researchers from Rice University have developed OpenSLS, an open-source, selective laser sintering (SLS) platform. OpenSLS, a modification of a commercial grade CO2 laser cutter, is at least 40 times cheaper than its commercial counterparts, and can be used to print 3-D objects using different powdered materials—including plastics and biomaterials.

The details and design specs can be found in an open-access paper published in PLOS ONE.

Using a combination of relatively inexpensive, over-the-shelf components (including open-source microcontrollers), the researchers were able to bring the cost of the OpenSLS down to less than $10,000, a figure significantly cheaper than commercial SLS platforms, which can range from $400,000 up to $1 million.

“SLS technology has been around for more than 20 years, and it’s one of the only technologies for 3-D printing that has the ability to form objects with dramatic overhangs and bifurcations,” said study co-author Jordan Miller. “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.”

The team was able to demonstrate that the machine could print a series of complex objects from both nylon powder—a common material in high-resolution 3-D sintering—and from polycaprolactone, a polymer commonly used as a substrate for studies on engineered bone.

“In terms of price, OpenSLS brings this technology within the reach of most labs, and our goal from the outset has been to do this in a way that makes it easy for other people to reproduce our work and help the field standardize on equipment and best practices,” said study co-author Ian Kinstlinger. “We’ve open-sourced all the hardware designs and software modifications and shared them via Github.”

Using Powder to Print Objects

OpenSLS differs from traditional 3-D printers by utilizing a different printing method. Most 3-D printers are "extrusion-based," meaning they create objects by squeezing melted plastic through a needle in the shape of two-dimensional patterns. These layers slowly build up to form a three-dimensional object.

OpenSLS instead uses the SLS laser to shine down onto a bed of plastic powder, melting or sintering at the laser's focal point to form a volume of solid material. A single layer is formed by tracing a two-dimensional slice of the object. Powder is then laid down on top of this layer and the process is repeated. Successive layers then form the final object.

Miller said, “Here, we have powdered biomaterials, and our heat source is a focused laser beam. Because the sintered object is fully supported in 3-D by powder, the technique gives us access to incredibly complex architectures that other 3-D printing techniques simply cannot produce."


Image of a nylon model of the arterial system in a mouse's liver, 3-D printed using the OpenSLS platform. Credit: Rice University

“You can actually cut most of the required parts with the same laser cutter you are in the process of upgrading,” Miller said. The machine would then cost around $2000 and upgrading an existing cutter would only take a couple of days.

While the printer demonstrates proof of concept, further research will be needed to see if the printer would be useful for bioengineering.

As it stands, OpenSLS is capable of fabricating wonderfully intricate objects, and it is precisely this sort of 3-D printer that is needed to replicate the immense complexities of biological structures.

And the future possibilities are practically endless.

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