CHICAGO—SHI Plastics Machinery Inc. of America (Booth N5563) is showing five Sumitomo injection presses at NPE, demonstrating injection/compression, ultrahigh- speed molding of thin-wall parts. The presses are running applications from disposable medical parts to food containers to audio components and optical sheets.
Sumitomo machines now have a compression/oscillating system available for both the fixed and the moving platens. That option had been available only for the moving platen. At NPE, an SG75M press is doing localized thin-wall molding, from the fixed platen, of two tiny circular indentations on parts with wall thicknesses of 0.014 inch. Sumitomo presses also now have an HP option for thin-wall molding. A maximum injection velocity of 311/2 inches a second is reached in just one-hundredth of a second. Braking takes only five-thousandths of a second. The quick braking eliminates flash.
In Chicago, an SG180M press equipped with an HP option is molding stereo speaker cones that measure 5.35 inches in diameter and have an outer edge thickness of six-thousandths of an inch.
The firm also has updated the injection/compression molding by adding an Ultra option, for thin-wall molding. Ultra gives stable, 1-micron-precision clamp positioning during injection and fast-responding mold closing during the fill stage. Ultra is being shown on an SH350A press molding optical sheets for lenses.