Lightweight Composites & Superfast Container Molding at Fakuma Show
Overmolded UD tapes replace organosheet with major weight savings. And 4 PP cups molded in 1.55 sec.
Last month’s Fakuma show in Germany hosted two demonstrations by Sumitomo (SHI) Demag in the areas of structural composites and high-speed packaging. Last year’s Fakuma show saw the company’s debut in the burgeoning field of injection molded composites, with the production of a nutcracker that involved overmolding of glass-mat/thermoplastic “organic” sheet, as well as placement of metal inserts. This year, Sumitomo Demag (U.S. office in Strongsville, Ohio) molded a redesigned stapler that was 25% thinner (3 mm vs. 4 mm) and 35% lighter (92 g vs. 142 g). A key difference was the replacement of organic sheet having 0/90° fiber orientation with three layers of unidirectional (UD) thermoplastic tapes. These tapes, made of Celstran CFR-TP PPGF70-013 (70% glass in PP) from Celanese (U.S. office in Irving, Tex.), allow lightweighting, thanks to more selectively directional reinforcement.
Another highlight of this exhibit is the loading of the tapes into the mold by a six-axis robot equipped with a heated gripper system, or “hot-handling device.” This device controls the preheating of the taps and is said to provide “gentler” temperature control and the option of shorter processing times.
The UD tapes were overmolded on a Systec Servo 210 servohydraulic press with 30% glass-filled PP. The nutcracker still utilized metal inserts, but its toothed structure is now formed of plastic ribs instead of exposed metal. Another new feature was the addition this year of in-mold foil decoration.
The second impressive demonstration at the show by Sumitomo Demag was billed as “the fastest exhibit at Fakuma.” An El-Exis SP hybrid machine produced four 125-ml PP gourmet containers in cycles of just 1.55 sec. The containers weighed 3.4 g each and had 83 mm diam. and 0. 32 mm wall thickness, with a flow-path/wall-thickness ratio of 213:1. They were demolded by a side-entry robot. (See Keeping Up section for more Fakuma news.)
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