Although vat photopolymerization has proven capable of producing high-resolution parts at high throughput, photopolymer resins often lack the physical properties necessary for end-use part applications. Metal desk (NYSE: DM) is looking to change that with the release of its DuraChain materials, which the company says overcomes these challenges.
Photopolymers for 3D printing are usually acrylate-based, resulting in fragile prints that can shatter on impact. Companies like Carbon are trying to solve this problem by using a two-part formula, in which additives, triggered by exposure to heat, increase the chemistries to deliver better performance.
In contrast, DuraChain relies on photopolymerization-induced phase separation (Photo PIPS), in which the materials phase separates into two parts at a nanoscopic level. With a long pot life of around one year, the material can also be stored for longer. The materials were developed by Adaptive3D, a Texas-based startup acquired by Desktop Metal in 2021. The startup’s predecessor material, ToughRubber, could have stretched up to 4.5 times its original length before recovering of the deformation.
“DuraChain photopolymers mark a new era in DLP printing that offers material properties that rival thermosets in a long-life material,” said Ric Fulop, co-founder and CEO of Desktop Metal. “Parts printed with DuraChain resins perform very well over a wide temperature range and offer other important benefits that will quickly lead to new material innovations in DLP printing.”
The traditional limitation to acrylates is partly due to the fact that most vat light-curing methods cannot handle highly viscous materials. This is partly because most digital light processing (DLP) machines rely on upward projection, projecting light through a transparent resin tank. Since more viscous materials are often heavier and require more energy, hanging them upside down on the build plate can be difficult.
Manufacturers love Strengthen, Formlabs and, more recently, BCN3D, have developed proprietary methods to process these thicker materials. For Desktop Metal, the solution is to 3D print these materials using the Xtreme 8K system from ETEC (formerly EnvisionTEC). The Xtreme 8K casts the light downward, bypassing the hanging problem.
Today Desktop Metal releases its first DuraChain materials, Elastic ToughRubber 70 and 90, offering different Shore A durometer values. While the former is only available in black, the latter is available in black and white, which can be dyed for a given application.
Demonstrating the utility of the materials, industrial vacuum maker Dustless Tools used the material to 3D print its DustBuddie for demolition hammers. This required a material with high energy return, tear resistance and resilience. Dustless suggests that the product, which collects dust from demo hammers, would have been prohibitively expensive for injection molding, given the niche segment. However, thanks to 3D printing, the company was able to bring the product to market.
To understand the material in a broader context, we reached out to David Walker, co-founder of Azul3D and president of the Photopolymer Additive Manufacturing Alliance Executive Advisory Board. About the hardware, Walker said:
“I think moving away from two-component resins is essential, it’s what consumers are demanding. That being said, PIPs are not such a new idea. There are several resin formulators that already use these types of techniques and I think it’s just not advertised or known. This will certainly help improve Desktop Metal’s materials portfolio, but we would need to see the materials datasheets to see what kind of impact it will actually have on the market. Also, Desktop Metal and [ETEC] don’t have great hardware pathways to print higher viscosity resins, like the new BCN3D photopolymer printer or Formlabs’ innovative Form 3 and 3L. Without these kinds of hardware innovations, there will always be bottlenecks.
Regardless of Desktop Metal’s specific products, the news reflects a shift in the market in which a wider variety of photopolymers are being introduced. With the companies already mentioned, Inkbit has expanded beyond acrylates. This will certainly mean greater advances in the field, as well as greater adoption and much broader applications for vat light curing.
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