Medical Molder Relies on 3D Printing to Speed Development of Inspection Fixtures

Founded in 2004, medical molder Medbio, LLC (Grand Rapids, Michigan) operates four facilities in the U.S. equipped with a total of 119 thermoplastic and two liquid silicone rubber (LSR) injection presses in ISO Class 7 or 8 certified cleanrooms. Together with its parent, plastics caps and plugs manufacturer Protective Industries Inc. (Buffalo, New York), the combined company operates 17 molding facilities globally.

To support active programs, Medbio produces or commissions 100 tight-tolerance injection molds annually to produce medical devices and diagnostic equipment. It’s no surprise that the company has been using polymer 3D printing — much of it conducted in house — for the last 5 years to produce prototype parts for new programs and after engineering changes, as well as for fixtures to support its extensive molding operations.

Interestingly, the company sets aside CAPEX funding every year for technology development, which enables Medbio engineers to purchase and try new equipment that might prove useful. That’s how its Grand Rapids team started working with polymer AM technology. It presently owns an FDM/FFF printer from Stratasys on which it prints polycarbonate/acrylonitrile butadiene styrene (PC/ABS) and PLA, and an SLA printer from Formlabs on which it prints epoxy.

“We primarily use our printers to test out jigs and fixtures to see if our concepts will work, as this gives us something we can hold, feel and turn around in space, plus we can quickly and inexpensively try multiple different versions of a design and see which works best,” Ethan Bruyn, Medbio manufacturing technology leader, explains. “Given the molding tolerances we have to maintain — often as tight as 0.002 inch [0.05 millimeter] — we have a large metrology department, so we do a lot of work developing holding fixtures, CMM fixtures, along with jigs for our assembly team. Once we’re sure a design will work, for the most demanding applications where anything that touches a molded part is required to have FDA approval, we either reproduce the design in anodized aluminum or stainless steel or machine it from a block of PEEK [polyetheretherketone]. For less sensitive programs that don’t require an FDA-approved material for part contact, we may keep the fixture in polymer additive.”

He notes that most of the company’s EOAT are produced in metals because of the amount of wear they experience on high-volume molding programs.

“While many companies are pushing 3D printed EOAT for everything, we like to assess each application and base the design and construction off the part, cycle time and degree of complexity required,” Bruyn adds. “We have fully 3D printed EOAT that have work out well, but we’ve had others where the frequency at which wear components needed to be replaced limited our ability to use the technology — especially when we needed to thread into plates. On the other hand, we’ve also had a situation where a conventional metal component for an EOAT was lost and, due to the long lead time for machining a replacement, we turned something around on our Stratasys in a day to get out of a bind versus waiting 2 weeks for a replacement to be machined. Overall, I think 3D printing has evolved a lot in recent years and I’m very curious to see what happens in the next 5-10 years.”