FITCHBURG, MASS. - Massachu-setts is becoming an East Coast center for rapid tooling-the pro-cess of creating molds from models made by rapid prototyping. Within the past year, at least two major firms involved in rapid tooling and prototyping have opened offices there. Both are connected with local universities.
3D Systems Inc., a Valencia, Calif., company that makes stereolithography equipment, opened an office at the Institute for Plastics Innovation, part of the University of Massachusetts at Lowell. Fraunhofer Gesellschaft, a German industrial research and development firm, has opened the Fraunhofer Resource Center at the former Fort Devens, and is affiliated with Boston University.
Officials from both companies presented papers at a regional technical conference, held in March at Fitchburg, in conjunction with the MassPlastics '96 show. The injection molding RETEC was sponsored by the Society of Plastics Engineers.
Rapid tooling is only a few years old, but it already is changing concepts about how injection molds are made, according to Colin Gouldson, tooling applications manager at 3D Systems in Lowell. The image of the solitary mold maker does not apply to rapid tooling, which requires more of a team approach under intense deadlines, he said.
``There are no cookbooks available, so team members bring whatever expertise they have to the project,'' he said at the RETEC.
He said an engineering team may consist of eight people: an engineer, computer-aided design person, mold designer, mold maker, technician, purchasing director, tooling vendor and molder.
Rapid prototyping itself is only about a decade old. Revenues topped $300 million in 1995, he said. Rapid tooling is the fastest-growing segment.
Rapid tooling can achieve lead times of three to four weeks and turn out a mold capable of producing small runs of as many as 50 parts, Gouldson said. Another speaker, Klaus Baden at Fraun-hofer in Boston, said the new materials soon will enable rapid molds to run 200-300 parts.
Stereolithography, using ma-chines built by 3D Systems and others, builds model parts one layer at a time from a bath of
liquid resin. Mold makers take those models to make molds using several processes, including sintered powder metal, casting and spray metal.
In his RETEC paper, Baden, a project manager, said Fraunhofer technicians have produced a mold out of epoxy in just 48 hours, using a model made on a 3D Systems machine. The mold was for a cap for a car's locking roof rack.
A third RETEC paper, by engineer Scott Dobson at Albright Technologies Inc., detailed a soft-surface method used by the Sterling, Mass., company that makes a mold in a week or less. The process has turned out more than 50 experimental molds.
Albright Technologies first suspends a model part inside an aluminum mold cavity. Then a thin layer of elastomer - Dobson would not identify the material - is cast around the part. No hand finishing of the mold is required, he said. The company typically is able to run about 50 parts on a soft-surface mold, but some molds have reached 100 or even 1,000 parts, he said.
Dobson said the technology competes with aluminum prototype tooling and urethane casting. Albright Technologies, which specializes in rapid tooling, began to develop the soft-surface tooling two years ago.