Integrated Multi-Process Cells Hum at Fakuma Show
Why not combine plastic injection with metal injection, or bead-foam molding, or laser printing?
Some of the most dazzling exhibits at recent plastics exhibitions have demonstrated intimate pairings of injection molding with other processes in an integrated cell. The Fakuma 2014 show last week in Friedrichshafen, Germany, was no exception. It showed how machinery OEMs are pulling out the stops to show that virtually anything can be integrated with injection molding.
KraussMaffei (U.S. office in Florence, Ky.) caught my attention (and that of a crowd of other visitors) with a two-shot molding cell in which a first shot of polycarbonate was overmolded with metal—yes, pure zinc metal. The technology was developed by German molder and moldmaker Krallmann Group, which also built the small metal-injection unit on the side of the press. That unit melts a billet of zinc at 250 C and injects it through a special hot runner. Shot capacity is up to 30 g (at a density of 7.5 g/cc). In this case, only 3.5 g of metal was injected to show the capability of adding conductive paths or electrical contacts to a plastic part (photo above).
Arburg (U.S. office in Newington, Conn.) operated a cell in which a bead foam molding press was integrated with an injection machine, using a six-axis robot to transfer foam components to the injection mold and to demold finished parts. The part was a socket consisting of a circular EPP foam part and a solid PP threaded component that was molded inside the foam I.D. According to Arburg, it’s not possible to achieve a permanent bond between the bead foam and solid PP without this overmolding process, which is called Particle-Foam Composite Injection Molding (PCIM). The photo above shows the part and how it can be incorporated into larger bead-foam components, represented in this case by an EPP board.
Although less exotic, close coupling of a laser printer to an injection machine is not something you see every day. Boy Machines (U.S. office in Exton, Pa.) ran a cell in which laser printing was performed side by side with the injection press molding an ABS “business card.” The laser printer was integrated with the machine controls, where the print program was selected.