Christopher Williams still remembers the day that changed his career path. “‘They say this machine can make anything,’” our professor told us. “‘Now go design something impossible.’”
That was in 1997, and Williams, a University of Florida undergraduate at the time, explained that his design engineering instructor had just unboxed the school’s first 3D printer. “That was our first assignment, and even though we didn’t have the skills or software back then to accomplish what Dr. Crane was asking, it was at that moment that I fell in love with additive manufacturing.
Now a professor at Virginia Tech, Williams gives the same task to his students in the Design, Research, and Education for Additive Manufacturing Systems (DREAMS) Lab. What’s different is that Williams’ students have a far greater chance of completing their assignments. Unlike that day 24 years ago when he and his fellow Gators had access to but a single 3D printer and no CAD software with which to design the impossible, those in the DREAMS Lab are free to experiment with more than two dozen additive systems, several of them custom designed and built by Williams and his students.
They also enjoy the use of topology optimization and generative design in their attempts to solve the thorniest of DfAM (design for additive manufacturing) challenges. Yet their efforts go well beyond any commercially available software systems as they work to design more efficient structures and deposition strategies, study material interactions at the molecular level, and develop better build monitoring and process control tools, all of which helps to pave the way towards industry-wide adoption of AM technology in all its many forms.
Based on the program’s success, it seems that—like their mentor—DREAMS students have developed a similar love affair with additive manufacturing (AM). Since opening the lab in 2008, Williams has mentored dozens of undergraduate students. Fifteen have gone on to earn master’s degrees, thirteen doctorates, and at least three have pursued post-doctoral research into 3D printing technology. Many of these graduates have since assumed AM-related roles in the aerospace, medical, and general engineering industries.
When not fulfilling his duties as DREAMS Lab director, Williams chairs SME’s AM Technical Community Leadership Committee, where he and other members serve to “showcase the innovative technologies represented by our technical groups to promote and accelerate adoption within the global manufacturing community.” Their work includes the sponsorship of career forums and educational events, digital manufacturing challenges, awards for industry achievement and technological innovation, and much more.
He’s well-equipped to do so. According to the DREAMS Lab website, Williams is an L.S. Randolph Professor of Mechanical Engineering, which he earned from the Georgia Institute of Technology in Atlanta. Over the past decade, he’s co-authored more than 185 peer-reviewed articles, nine of them receiving Best Paper awards at international design, manufacturing, and engineering education conferences.
He was also awarded the 2012 International Outstanding Young Researcher in Freeform and Additive Manufacturing Award, the 2013 National Science Foundation CAREER Award, and the 2010 Emerald Engineering Outstanding Doctoral Research Award in the area of Additive Manufacturing, not to mention his many recognitions for classroom achievement.
Yet Williams is quick to point out that DREAMS is not about him or his accomplishments, but rather the young people who come here to learn about this transformative manufacturing technology; it’s about what they have discovered thus far and all they have yet to discover going forward. “We do a tremendous amount of research across the entire AM value chain,” he said. “That means everything from designing new materials and printer capabilities to developing better software tools and process controls. It’s a lot of ground to cover, but we’re very fortunate in the opportunities we have available to us.”
Part of the challenge lies in the sheer breadth of AM technology in use today. As Williams pointed out, seven distinct classes of 3D printing exist today, and his lab experiments with six of them. And except for the student-built custom equipment mentioned earlier, all are machines that a graduating student would find at an increasing number of workplaces, allowing them to prepare for their own future while bringing value to a potential employer. These include metal and polymer powder bed fusion, binder jetting and material jetting, fused filament fabrication, vat photopolymerization, and direct energy deposition. The only one not covered is laminated object manufacturing, or LOM, a niche process that uses paper, plastic, and sometimes metal sheet stock for component production.
“Much of what we do here goes back to that first assignment: designing and then building the impossible,” said Williams. “When I was in graduate school, that was the creation of then-novel geometries such as lattices, honeycombs, and similarly optimized shapes. Those structures are fairly routine now, which is why our lab is working more on functionality over shapes. For instance, one of our students recently completed a project where he embedded RF (radio frequency) structures into a 3D-printed part, while another incorporated motion actuators. These are just a few of the advanced capabilities we’ve developed that, until recently, were either impractical to produce, or as Dr. Crane suggested so long ago, downright impossible.”
In addition to smart devices like those just described, Williams and his team have built a so-called “Dream Machine,” a multimodal, open-source 3D printer that reportedly supports binder and material jetting, vat photopolymerization, and extrusion of both paste and filaments, all from a single platform and with a head that allows automated, in-process technology switching.
Another DREAMS Lab development is a multi-axis robotic printer that breaks the traditional one-horizontal-layer-at-a-time paradigm in favor of true three-dimensional printing. Said Williams, “When you can lay down fibers in any direction, it allows you to orient the strands along the load path, which in our tests produces at least a two-fold improvement in product strength.”
Novel AM processes are but one of the department’s four Thrust areas. Another is materials development and certification. Williams noted that much of AM’s long-term potential revolves around the creation of new polymers and metal alloys, and here again, the DREAMS Lab doesn’t disappoint. The team there has developed dissolvable polymers and ones that mimic human tissue, both for medical use. They’ve found ways to extrude semi-crystalline polymers, 3D printed latex nanocomposites and multi-material microstructures, and used vat polymerization to produce parts from all-aromatic polyimide (more commonly known by its trademarked name, Kapton). As Williams pointed out, this last material is especially interesting.
“The stuff is amazing,” he said. “It has the best flammability rating of any polymer out there. It’s also quite tough, non-conductive, and very resistant to radiation and temperature extremes, which is why NASA uses it for spacecraft and satellite shielding. Until now, though, it was only available in sheet form and from a single supplier. Virginia Tech has changed all that with the development of a 3D-printable polyamide that will open the door to a huge number of new applications.”
One crucial but often overlooked aspect of manufacturing today—additive or otherwise—is cybersecurity. No, this isn’t the act of installing firewalls or securing passwords (although both are important) but rather the development of what Williams calls anti-counterfeiting technology. Such technology mandates that each 3D-printed component receives its own unique digital fingerprint, one that is not only indelible but also invisible to bad actors, eliminating the potential for unapproved, possibly malicious manufacturing.
“We also focus heavily on cyber-physical security,” Williams said. “For instance, we’ve shown that it’s possible to give 3D printing software a virus such that every part it produces contains a small void or similar flaw. We’ve also shown that industrial printers are susceptible to attacks where the laser power or temperature of the powder bed is changed without the operator’s knowledge, resulting in reduced part quality or crashed builds. These are just some of the vulnerabilities inherent to digital manufacturing.”
The DREAMS Lab plans to prevent such potential attacks by developing internet-independent, black-box systems that sit inside the 3D printer and monitor the part, equipment, and operating parameters during the build. This will validate that the product was made to the intended specifications while also watching the data stream to and from the machine, providing a level of trust that Williams said does not currently exist.
Hackers and bad actors aside, Williams remains madly in love with 3D printing. Perhaps more important, however, is his love of teaching others about it. “What’s always fascinated me about additive is that we as designers no longer have to sacrifice our vision to fit within the constraints of traditional manufacturing processes. Instead, we have a technology that can literally place material anywhere in three-dimensional space. It outpaces our imagination. That’s why I like my job, and why I’m so passionate about sharing what I know with others. It’s a really exciting time for all of us.”
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