Lawrence Livermore National Laboratory
Several research teams developed a novel type of additive manufacturing using laser beams and resin.
3D printing is one of the most popular ways to build and construct unique ideas among researchers and engineers. The process expands the possibilities of what a team can create by removing traditional limitations. However, one of the most constantly mentioned downsides to 3D printing is that it's incredibly time-consuming. Depending on the size and intricacy of a design, a single part can take hours or even days to fully print.
One research team is trying to cut down on the wait time for projects by using hologram-like renderings. A group from Lawrence Livermore National Lab joined forces with a team at UC Berkeley, University of Rochester, and MIT to create the super-fast 3D printing strategy. Simply put, three laser beams overlap to define an object's geometry from three different directions. That creates a 3D image suspended in a vat of photosensitive resin.
Then, a laser light stays on for just long enough to cure the shape. Excess resin gets drained out and what remains is a fully-formed 3D shape.
"The fact that you can do fully 3D parts all in one step really does overcome an important problem in additive manufacturing," says LLNL researcher Maxim Shusteff. "We're trying to print a 3D shape all at the same time. The real aim of this paper was to ask, 'Can we make arbitrary 3D shapes all at once, instead of putting the parts together gradually layer by layer?' It turns out we can."
The researchers concluded that the process is considerably faster than other polymer-based methods of printing, and it's faster than nearly all other additive manufacturing methods used in factories.
"It's a demonstration of what the next generation of additive manufacturing may be," says LLNL engineer Chris Spadaccini. "Most 3D printing and additive manufacturing technologies consist of either a one-dimensional or two-dimensional unit operation. This moves fabrication to a fully 3D operation, which has not been done before. The potential impact on throughput could be enormous and if you can do it well, you can still have a lot of complexity."
Thus far, the team has printed planes, struts, and beams — all at complex angles and with unique curvatures. Shusteff noted that while conventional 3D printing can't really span structures that might sag without support, volumetric printing can produce curved surfaces without layering artifacts.
"This might be the only way to do AM that doesn't require layering," Shusteff said. "If you can get away from layering, you have a chance to get rid of ridges and directional properties. Because all features within the parts are formed at the same time, they don't have surface issues."
The team admits that the project does have its limitations. Due to the beam placements, there are certain complexity restrictions on just how detailed the beams can get. There also still need to be improvements with regard to the resin in order to better craft the structures.
"If you leave the light on too long it will start to cure everywhere, so there's a timing game," Spadaccini said. "A lot of the science and engineering is figuring out how long you can keep it on and at what intensity, and how that couples with the chemistry."
The researchers hope that this new type of printing would help inspire other innovators to apply different materials.
"I'm hoping what this will do is inspire other researchers to find other ways to do this with other materials," Shusteff said. "It would be a paradigm shift."