Traditional 3D printing that is commonplace today can often take a very long time to create an object. This is because the printer must complete one layer at a time, sometimes requiring hours or at times days to complete the entire printing process. However, a team of scientist and engineers led by the Lawrence Livermore National Laboratory (LLNL) have developed a new 3D printing process that uses lasers said to be hologram-like to create an entire 3D object in just seconds.
The lasers create the objects inside a tank of liquid resin, and the new technique is called volumetric 3D printing. The team working on the project believes that volumetric 3D printing can overcome many of the limitations seen in current additive manufacturing processes, commonly called 3D printing.
Current 3D printing solutions either build up layers of molten plastic until the desired object is complete, or lay down layers of metallic powder for metal objects that are fused into a pattern using a laser or electron beam. The object built with these common processes also need to be locked into structures to support the unit until it is complete.
The new volumetric 3D printing process by comparison creates the entire object at the same time by using overlapping laser beams that create a hologram-like pattern in a transparent tank filled with a photosetting plastic resin. By combing three lasers the team was able to induce curing in the resin and create the desired object in about ten seconds. Once the forming process is complete, the remaining resin is drained from the tank leaving the finished object.
"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."
Since the entire object is created at once in this process, there is no need for support structures of any type. The team has used the volumetric process to create squares, beams, planes, and struts. Objects can also be printed at arbitrary angles, lattices, and with complex curves. The process will also work in weightlessness making it usable aboard spacecraft.
One downfall to the process is that there is a limit to how complicated shapes can be and on print resolution. If the resolution is increased too far, parts of the liquid resin not wanted in the finished object can be cured by mistake.
"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."