Imagine a world of manufacturing no longer constrained by complexity or traditional materials, and where previously impossible engineering designs are suddenly possible. That's the promise of additive manufacturing (AM), the focus of the latest episode of the Big Ideas Lab podcast. The episode delves into the past, present and future of AM, featuring experts from Lawrence Livermore National Laboratory (LLNL) and the University of California, Berkeley (UC Berkeley). Listen on Apple or Spotify.
Unlike conventional methods that carve objects or components from a building block of material, AM - commonly known as 3D printing - adds material to create a final product, often in a layer-by-layer approach. This fundamental shift in manufacturing offers remarkable advantages, from geometric freedom to unprecedented customization.
As described in the episode, the AM journey began in the 1980s with Charles Hull, who invented stereolithography. Hull's pioneering work laid the foundation for modern 3D printing, transforming liquid resin into solid plastic using lasers. Fast forward to today, and LLNL is pushing these boundaries even further.
LLNL Materials Engineering Division Leader Chris Spadaccini recalls the Lab's early AM projects: "We started to think about how [to] make small-scale systems, like microchips, but mechanical systems that are three dimensional?" Their team's work with projection micro-stereolithography led to breakthroughs in creating intricate, tiny 3D structures.
As the technology progressed, the appeal of AM became its versatility. Traditional manufacturing techniques often require costly molds and tools, making customization a challenge. With AM, every part can be unique without disrupting the production process.
As LLNL Group Leader Maxim Shusteff explains: "The promise of additive is that every structure can be different, so you don't have to make the same structure twice." This flexibility allows applications ranging from dental implants and prosthetic limbs to aerospace components - but the real magic of AM lies in its ability to create designs that were previously unimaginable.
"What additive manufacturing gets you is a high level of geometric complexity," Spadaccini said. "You can make incredibly complex components that you could not have made any other way." By allowing internal structures to be optimized for strength, weight or other properties, AM enables the production of lighter, stronger parts, Spadaccini explained.
Volumetric Additive Manufacturing: a new frontier
Among the exciting advancements discussed in the episode is Volumetric Additive Manufacturing (VAM). Unlike layer-by-layer approaches, VAM creates entire objects in one piece by projecting light into a rotating vat of photosensitive resin. Caitlyn Krikorian Cook, a polymer engineer at LLNL, describes the process: "You take a three-dimensional image, cut it into radial slices, and you project those slices into the resin… as that vat rotates, the part is able to actually realize or become a solid all at once in that photosensitive resin."
This innovation offers smoother surfaces, delicate geometries and faster production times. Additionally, higher viscosity materials can now be used, leading to stronger and more versatile components.
"With low-viscosity materials, typically those materials are pretty hard and can be brittle at times, and so now you can significantly improve your properties," Cook said. "You can have parts that are elastomers, are squishy, can be used for energy absorption and can have shape-changing properties, so it's just a lot more functionality that you can impart in some of the materials that you would be able to print with. We see it as an advantage."
The episode also explores how 3D printing is venturing into new realms. One promising area is bioprinting, where LLNL is developing techniques to print biological materials.
"What we're trying to do is create an entire structure in one step, there's a lot less movement of the material," Shusteff said. "That approach in general is very good for these soft materials that are relevant in biology and in life sciences."
Applications include artificial organs, drug testing systems and hybrid organic-inorganic materials that combine the best of nature and engineering.
Another groundbreaking innovation is Computed Axial Lithography (CAL), a Star Trek replicator-like process that builds objects using principles similar to a CT scan, but in reverse, and does so quickly and seemingly out of thin air. Hayden Taylor, associate professor of mechanical engineering at UC Berkeley, explained: "[CAL] allows us to print materials that are very low in stiffness inherently; things like hydrogels, which are water infused polymers that are very low in stiffness… and because we are not using layers to print the object, we can get relatively smooth surfaces on the printed part." This approach is proving ideal for optical components and other applications requiring smooth, precise surfaces.
Despite its transformative potential, AM is not without challenges. Material defects and the complexity of processes mean traditional methods still have an edge in reliability for certain applications. Spadaccini said: "With additive manufacturing, you're melting something, you're converting it from a liquid to a solid, you're doing something to it to turn it into the final material and component simultaneously. You can have material defects because of that. There's a lot of deep science and engineering that goes into understanding that, and that's what we try to really do here at the Lab."
However, these challenges are being tackled through interdisciplinary collaboration, as LLNL is combining expertise in optics, mechanical design, photochemistry and computational imaging to push the technologies forward.
The episode concludes with a look toward the future, as new AM advances are set to revolutionize a broad range of industries, including Cook's research in sentient materials that "can dynamically adapt to its structure and shape in response to environmental changes," like a synthetic version of a biological organism.
As Shusteff said, the next stage in AM will be shaped by curiosity. "It's almost a given with folks who are scientists and engineers, because they tend to come with that mindset."
Listen the Big Ideas Lab podcast here on Apple or Spotify.
