In Search of Production-Grade AM Polymer
Raymond Weitekamp, a Caltech materials researcher, develops aerospace- and automotive-compatible polymer
May 20, 2022
Raymond Weitekamp readily admitted he was at first an AM (Additive Manufacturing) skeptic. Looking at the objects made with early 3D printers, he felt the technology was good enough to produce shiny toys for display, but not much else. The main letdown, he said, was the quality and variety of the materials available. But he also happened to have a PhD in chemistry, making him an ideal candidate to address the shortcoming. What he came up with was COR (currently in Alpha), a polymer material that he believes can compete head-to-head with molded engineering plastics.
Raymond's idea a quick-and-dirty stress test was to print three identical parts—one with COR, two with other types of materials—and subject them to a blender cycle. He has video evidence to prove COR survived the test; the others didn't (see below). “We broke the first blender we tried this COR alpha 3D printed part!” he proudly noted.
COR is the core of his startup PolySpectra, located in a shared office complex in west Berkeley, looking out to the Berkeley Marina.
Triggering Olefin Metathesis Using Heat
Raymond developed COR based on Olefin Metathesis, described by the Organic Chemestry Portal as a chemical reaction that “allows the exchange of substituents between different olefins.” One of the noted authorities on this sibject was Robert Grubbs, winner of the 2005 Nobel Prize for Chemistry and Raymond's PhD advisor. “What I developed was a method to use heat to activate this chemical reaction,” explained Raymond.
Raymond recalled a six-year-old conversation with a sales rep from the leading AM hardware maker Stratasys. In it, he was told a polymer with both durability and temperature resistance would be the Holy Grail. So he set out to create a polymer that can satisfy both. This month, PolySpectra's COR became available for Stratasys printers.
In the press announcement, Stratasys wrote, “Materials developers contributing new Open materials to the program include Covestro, Evonik, Arkema, Forward AM from BASF, Mechnano, Tethon 3D, Liqcreate, and polySpectra ... The materials can be purchased directly from material partners or their distributors and are designed for advanced users for testing, development, and end-use parts with exotic or novel properties.”
Moving Away from the Disposable Culture
Just because you can print, doesn't mean you should, Raymond cautioned. “Does it really make sense to 3D-print disposable spoons and forks?” he asked. Selecting the correct application will go a long way toward sustainability, he said.
“Just by printing the part in the same continent where you want to sell, you are already cutting down the carbon footprint significantly,” Raymond pointed out.
Global supply chains with low-cost laborers in far-flung regions may give you an economic advantage, but the price paid in carbon footprint from transportation is the invisible cost. Distributed manufacturing was once viewed as the smart move, but “the COVID shutdown was a wakeup call” to its vulnerabilities, Raymond noted.
Raymond and his team are developing end-of-life strategies for PolySpectra's COR. “I also want to explore applications that encourage long-lasting parts, not temporary-use disposable parts,” he said.
During the COVID shutdown, Raymond used his free time to learn 3D modeling in nTopology, an AM-targeted generative design software program. The lattice-filled parts he has been showing to the press, are sculpted by him.