Orlando, Fla. — There's a lot of buzz about 3D printing of liquid silicone rubber, and R.D. Abbott Co. Inc. and M.R. Mold & Engineering Corp. attracted attention at NPE2018 with live demonstrations of the process.
R.D. Abbott has had a 3D printer from German RepRap GmbH at its lab in Cerritos, Calif., since late 2016. The company brought the machine to NPE in Orlando in May to promote the process.
It also gave the companies the opportunity to tease the results of new studies that compare 3D printed LSR parts with injection molded parts.
"Knowing that design engineers are looking for not just fit, which they get out of a rigid plastic, or form, which they get out of a mock-up soft plastic, but they're also looking for functional requirements," said Rick Ziebell, vice president of technology at R.D. Abbott.
"So we looked at heat-resistant studies, and we've looked at materials' resistance to certain environments and compared it to injection molded silicones, and we find that it can handle continuously 200° C, and it's as resistant to UV and steam and other environmental influences in the same manner we would expect from an injection molded LSR part."
"So the design engineer can rely on that for an iterative design process that improves speed to market. Before, we had to generate a prototype cavity, which would take days or weeks, and each iteration took its own cavity. Today, just from step files from any CAD program, we can generate to the design engineer any level of modifications to the part in just hours. Those then can be taken and put in true functional service at temperature within the environment — let's say it's an automotive design — and be looking at long-term resistance wearability factors," Ziebell said.
Ziebell said R.D. Abbott would present the findings of the study at three conferences later this year.
The technology is still new and only recently patented. Ziebell said he could not disclose the names of customers using the 3D printers to create prototype parts. But he said it will soon have customers moving from the prototype stage to full-scale production.
"We expect this technology to take off towards the end of this year and into next year," Ziebell said. "This is true innovation work, and our printer is really the first of its kind."
R.D. Abbott sees the technology as a way to help mold makers and molders get parts to market faster. R.D. Abbott is working with M.R. Mold, a Brea, Calif.-based toolmaker, to commercialize the process.
The idea is that R.D. Abbott will help customers finalize part designs in record time, then M.R. Mold can build a production tool. Designers end up shaving weeks or months from the development timeline, with fewer tweaks and prototype tools.
"This is about helping our customers speed time to market," said Geri Anderson, marketing director for M.R. Mold. "It's speeding up the process. If you took a program that might usually take a year, with this it might only take nine months now which to everyone is very important.
"There's a lot of buzz about what this machine can do and can't do, and there's a learning curve because in the LSR world there hasn't been anything like this," she said.
Anderson and Ziebell said another advantage to the RepRap technology is that customers can keep intellectual property in-house, rather than send part designs to third parties for 3D printed prototypes.
The RepRap liquid additive printer is designed to exclusively use 3D-specific LSR grades from Dow Performance Silicones. The company currently offers 30, 50 and 70 durometer grades of resin.
The machine makes parts by adding successive layers of the printable Silastic LSR resins in a method comparable to RepRap's fused filament fabrication 3D printers.
The Dow materials were formulated for designers seeking to combine the performance benefits of silicone with the design and processing advantages of the additive manufacturing process.
Prior to NPE2018, R.D. Abbott demonstrated the printer at the ACS Rubber Division's International Elastomer Conference in 2017 and at the Medical Design & Manufacturing West show in Anaheim, Calif.