3D Printing

Laser holograms create 3D-printed objects in seconds, no layering required

Laser holograms create 3D-prin...
Volumetric printing replaces layering with a process that creates the entire object simultaneously
Volumetric printing replaces layering with a process that creates the entire object simultaneously
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Volumetric printing replaces layering with a process that creates the entire object simultaneously
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Volumetric printing replaces layering with a process that creates the entire object simultaneously
There is a limit to how complex shapes can be at this stage of the research
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There is a limit to how complex shapes can be at this stage of the research
Volumetric printing is not only faster, but eliminates the need for temporary support structures, is more flexible, and provides more geometric flexibility
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Volumetric printing is not only faster, but eliminates the need for temporary support structures, is more flexible, and provides more geometric flexibility

How do you create complex 3D-printed objects in seconds, instead of hours or days? A team of scientists and engineers led by Lawrence Livermore National Laboratory (LLNL) has developed a process that uses hologram-like lasers to make complete objects in seconds inside a tank of liquid resin. Called volumetric 3D printing, the process overcomes many of the limitations of conventional additive manufacturing.

Additive manufacturing, better known as 3D-printing, promises to revolutionize prototyping and manufacturing, but it's a process that, for all its promise, has its limitations. Conventional 3D-printing works by printing an object in layers. Plastic objects can be built up by squirting molten plastic in a three dimensional pattern and metal objects by laying down layers of fine metallic dust, which is fused into a pattern using a laser or electron beam.

It's a process that allows prototypes to be produced much more quickly than machining, and it allows very complex shapes to be made in a single unit instead of being built up from several simpler units. However, such printing can still take hours or even days, and while the object is being printed it may be necessary to include ridging or temporary structures to support it until it's complete.

Volumetric printing is not only faster, but eliminates the need for temporary support structures, is more flexible, and provides more geometric flexibility
Volumetric printing is not only faster, but eliminates the need for temporary support structures, is more flexible, and provides more geometric flexibility

Developed by LLNL in collaboration with UC Berkeley, the University of Rochester, and MIT, volumetric printing replaces layering with a process that creates the entire object simultaneously. It does this by using three overlapping lasers beamed in a hologram-like pattern into a transparent tank filled with photosetting plastic resin. A short exposure by a single beam isn't enough to cure the resin in a short time, but combining three lasers can induce curing in about ten seconds. After the object is formed, the excess resin is then drained off to reveal the complete unit.

"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."

Volumetric printing is not only faster, but eliminates the need for temporary support structures, is more flexible, and provides more geometric flexibility. So far, it's been used to create squares, beams, planes, struts at arbitrary angles, lattices, and complex, curved objects.

There is a limit to how complex shapes can be at this stage of the research
There is a limit to how complex shapes can be at this stage of the research

However, the team points out that there is a limit to how complex shapes can be and the resolution can only be increased so far because the increased exposure will cause unwanted parts of the liquid resin to cure. The hope is that the development of more responsive polymers will not only allow for larger objects with higher resolution, but also the printing of objects out of ultralightweight hydrogels. In addition, volumetric printing works in weightlessness, making it useful for manufacturing aboard spacecraft.

"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."

The research was published in Science Advances.

The video below shows the process in action.

Source: LLNL

3D Printing in a Fraction of the Time

4 comments
MD
Nice, for very small objects The notion of "making a 3d object all at once" is disingenuous. There is still a scanning laser motion involved. As to the programmed motion of that laser Is up to the system designer. Stereolithography (SLA) type printing using layers allows a resin which is partially opaque to the light source, curing little by little. Also using a focused laser (on a focal plane) allows for a tighter high intensity beam for precision. Scanning in "other than a layered format", both the uncured and cured resin must be transparent at the activation frequencies of the beam. That they are using 3 beams indicates that they are still using a "layered"/planar approach (circles of coincidence, with uncontrolled radials), if they were really wanting to control the high intensity "dot size", and protect the uncured resin from over exposure surely a truly 3D arrangement of beams would be desirable, minimum of 4 beams to be optimal (likely - spheres of coincidence). the secret to manufacturing in 3D, quickly, is all in getting the laser beam energy to transfer to the photo-resin without causing undesirable effects (voids etc). Power and satisfactory absorption rate. lol.
Roger Garrett
First of all, this does not in any way employ holograms. It uses lasers, but not in any holographic sense. So the headline and some of the descriptions in the video are simply wrong. But secondly, and most frustrating to me personally, is that I wrote one of my "Inventor's Sketchpad" columns in the old Interface Age magazine back in the 70s describing my own idea about how lasers and light-curing resins could be used to do almost exactly what this "new" development is doing. The responses I got to that column back then was, "You can't do that". Well, I guess you can. :( Contrary to what was said in the first comment, by "MD", there actually is no scanning involved. Each laser beam is shaped appropriately and only in those sections of the volume where the three beams intersect is the resin cured by the beams. So, yeah, it does it "all at once" but the complexity of the objects is severely limited. It can do really simple shapes, as they've already done, but anything even remotely close to common 3D printed objects is utterly impossible by this particular approach.
dougspair
....slight improvement over the 20 year old original....but is the resolution/finish any better...?
Saigvre
Printing the entire Warby-Parker lineup to try on at home is a ways off all right; those are 2-6mm wireframes and lames (on a perforated steel platen) made from a phase-only SLM (spatial light modulator) eather than film. Stepping and repeating is left as an exercise to the industrious elf! No far xray wiggler required! They managed an overview of where it fits in 3D methods in their 6 pages (plus supplement) there, and a nice big figure 1 (mouse up off the foreground image to lose the obscuring caption.) But hey, there's the guide to kid books for xmas too http://science.sciencemag.org/content/358/6368/1244.full