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Researchers are thinking about 3D printing in a new light

Research laboratories are exploring the use of multiple light sources to 3D-print parts all at once

Additive manufacturing (AM) has been a bottoms-up technology since its inception, with 3D parts being built layer upon layer until completion. Lately, though, researchers have been looking for alternative approaches that are faster than layering and prevent some of its inherent problems, such as stair-stepping—the formation of seams between layers that degrade surface finish.One popular area of exploration is using a light source, or sources, to solidify a complex 3D part in toto.

Called “volumetric photopolymerization,” the technology reportedly allows AM parts to be built up to 100 times faster than is possible with layering methods.Numerous research groups have reported progress in this area in the past three months:

Lawrence Livermore National Laboratory’s process involves using three laser beams to define the geometry of the part to be printed in a vat of resin. The intersecting beams create a 3D image that resembles a hologram. The lasers are activated for about 10 seconds. The resin cures at the points where the beams intersect.

• With the University of California Berkeley system, a series of 2D images of a 3D object are projected, like a movie, into a clear, rotating container of photosensitive resin. Each projected image passes through the material from a different angle. The material solidifies into the desired 3D shape when exposed to the projected light for a specified period of time.

• The University of Michigan has developed a technique that “lifts” complex shapes from a vat of liquid up to 100 times faster than conventional 3D printing processes, according to an article posted on the website of the university’s engineering department. The printer solidifies liquid resin with two lights that control where the resin hardens and where it remains fluid.

Does volumetric polymerization mean the end of layer-by-layer AM technology before it’s even gained a toehold in manufacturing? Hardly.

Research is a long way from commercialization of an industry-ready product or technique. However, those of us interested in the growth of 3D printing should be heartened that such research—and research into other methods for speeding up production—is occurring. It means the AM sector is aware of the technology’s problems and is taking steps to solve them.

About the Author
FMA Communications Inc.

Don Nelson

Editor-in-Chief

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Don Nelson has reported on and been in the manufacturing industry for more than 25 years.