Engineers turn laser cutter into an open-source 3D printer

Bioengineering researchers at Rice University have made an open-source laser sintering printer by modifying existing laser cutting technology. The new platform, OpenSLS, was adapted from a commercial-grade CO2 laser cutter and has the ability to print complex 3D parts from powdered plastics and biomaterial.

Researchers in the Miller Lab at Rice University’s Department of Bioengineering used a commercial-grade CO2 laser cutter to create OpenSLS, an open-source, selective laser sintering platform.(Photo by Jeff Fitlow/Rice University)

The system includes low-cost, open-source microcontrollers and electronics, including Arduino and RAMBo boards. By leveraging existing technology, engineers were able to build OpenSLS for under $10,000, which is 40 times less than traditional counterparts.

“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,” says study co-author Jordan Miller, an assistant professor of bioengineering at Rice who specializes in using 3D printing for tissue engineering and regenerative medicine.

For the most part, SLS machines, which have been around for the past 20 years, don’t allow users to create objects with their own powdered material. Having the capability to print with different biomaterials is important for researchers, explains Miller.

One of the advantages from starting the project from a CO2 laser cutter was the similarities in design needs. “The cutter’s laser is already in the correct wavelength range — around 10 micrometers — and the machines come with hardware to control laser power and the x-axis and y-axis with high precision,” Miller said.

Rice University’s Ian Kinstlinger with a nylon model of the arterial system of a mouse liver that he printed with OpenSLS. (Photo by Jeff Fitlow/Rice University)

The team demonstrated that the machine could print a series of intricate objects from both nylon powder — a commonly used material for high-resolution 3D sintering — and from polycaprolactone, or PCL, a nontoxic polymer that’s commonly used to make templates for studies on engineered bone.

The OpenSLS constructs parts by using a laser that points to a bed of plastic powder, melting or sintering it, forming a small volume of solid material. The laser traces in 2D, fabricating a single layer of a final part. After each layer, a new layer is laid down and the laser retraces it.

Miller explains that the process can be compared to creating crème brûlée, where a chef sprinkles a layer of powdered sugar, uses a torch to head the surface, melting the powder and forming a solid top layer. Instead of powdered sugar, the team is working with powdered biomaterial and the heat source is a focused laser beam.

“Because the sintered object is fully supported in 3D by powder, the technique gives us access to incredibly complex architectures that other 3D printing techniques simply cannot produce,” Miller said.

Miller also adds that their work with the OpenSLS provides the scientific community with an accessible platform for the study of laser sintering and the fabrication of complex geometries in diverse plastics and biomaterials, a win for the open-source community.

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