Officials of injection molding companies became students once again at Penn State Erie's three-day Injection Molding: Innovation and Emerging Technologies Conference.
During the event, held June 13-15, attendees heard presentations about medical molding, liquid silicone rubber, mold-filling simulation, automation, process monitoring, rapid prototyping, micromolding and other topics. Then they participated in hands-on tutorial laboratories on molding machines at the college.
Executives of Plastikos Inc. explained how the Erie connector molder is moving into medical. That included adding a small clean room. “[Medical customers] really don't want to take the risk if you don't have a clean room in place,” said Robert Cooney, manufacturing manager.
Philip Katen, Plastikos' general manager and president, recommended that newcomers to medical molding start off small and flexible, with the ability to add more work. “The right people, training processes and equipment is absolutely necessary to get into the medical industry,” he said.
Attendees also heard from automation suppliers Wittmann Battenfeld Inc. of Torrington, Conn., and Sepro America LLC of Pittsburgh.
Tom Betts, Wittmann Battenfeld's regional sales manager, said automated work cells give medical molders control over the process and can add value through part separation, inspection through cameras of thermal imaging, decorating and packaging. Often, a robot removes a part and hands it off to a secondary fixture for downstream steps.
Side-entry robots are usually the choice for molding cycles under 10 seconds, Betts said.
Jim Healy, Sepro America's vice president of sales and marketing, covered robots used in automotive and electrical, as well as medical. Robots can be used to add fasteners and inserts, but the molder needs dedicated, highly engineered tooling, he said.
“An end-of-arm tool is going to bring success or failure to any part,” Healy said.
Arburg Inc.'s Martin Neff explained the demands of LSR injection molding machines, including very accurate parallel platens to avoid flash, and a controller specifically designed for the material. “You need to have a precise mold and you need to have a precise process,” said Neff, who is manager of Midwest sales and engineering at Arburg's technical center in Elgin, Ill.
Experts also discussed the use of scientific molding and mold-filling simulation software.
RJG Inc.'s regional manager, Jon Newsome, presented a case study of a new mold for a CareFusion Corp. vial adapter. CareFusion used outside mold makers, and typically did not get involved in the mold design until the end, he said. But that changed. “The key here was starting this process early, getting the key people involved early,” he said.
Originally, the vial adapter used two molds. The material is sensitive to shear, viscosity changes and other variables. Newsome said the problem was regular blockage of mold cavities and balancing the cavities.
So Traverse City, Mich.-based RJG helped design a single 16-cavity mold, using the principles of scientific molding. A team of officials from CareFusion, the mold maker and the molder were involved from the beginning, Newsome said. A thorough mold simulation was done to determine the best location for cavity-pressure sensors.
“The whole process of how the material flowed, how the material sheared, was done before the steel was ever cut,” he said. “Everybody had the chance to sign off or dispute or change, before the mold was made.” The molder bought a new, dedicated press for the job.
All three parties — the molder, mold maker and CareFusion — had RJG master molders on staff. “The template we're interested in is how the plastic behaved, not how the machine behaved,” Newsome said.
“The whole notion of doing simulation upfront is how to get it right the first time,” said Jack Doolittle of TPSteck LLC. He said the Sigmasoft process simulation software examines the entire mold in a three-dimensional image, including runners, gates and inserts, and shows how the mold will fill, giving shear rates and temperatures.
“All of this information allows us to design efficient molding cycles,” Doolittle said. There has been great improvement in 3-D simulation of injection molding in the last five to 10 years, he added.
John Beaumont, president of Erie-based Beaumont Technologies Inc., gave a brief history of that simulation. The big breakthrough came in the late 1970s, when Australian plastics consultant Colin Austin founded Moldflow Corp. and introduced the first commercial simulation programs. Moldflow went public in 2000 and used the proceeds to buy its main competitor, AC Technology. In 2008, Moldflow was bought by Autodesk Inc.
Beaumont said 3-D simulation began to appear around 2000, and the software became easier to use. Growth took off.
But that ease of use has obscured the very complex mathematics that goes into simulating the injection molding process, said Beaumont, who chairs Penn State Erie's Plastics Engineering Technology program.
“The heart of it, of course, really comes back to mold-filling simulation. If you don't have that right, you can't have the rest right,” he said. “You have to have the fundamentals.”
Rapid prototyping is much more than just making sample parts, according to Matt Hlavin, CEO and president of custom injection molder Thogus Products Cos. The company in Avon Lake, Ohio, has invested heavily in the technology, buying Stratasys machines.
Thogus also makes its own fixtures and end-of-arm tooling. And the company can use direct-metal laser sintering to make molds to get production going quickly, and even make molds with conformal cooling, he said.
“We're now printing most of our mold-cavity blanks before we cut steel, and then take it over to our mold maker,” Hlavin said.