Electrically Driven Injection Molding Machines
During the past few years attempts have been made to replace hydraulic drives for injection molding machines by electric drives, because more precise control. As electric drives for the clamping unit and the injection unit of injection molding machines frequently screw drives are used in which the movable tool clamping plate or a screw of the injection unit is operated via a worm gear spindle. In applying the clamping forces of the high injecting pressure large axial forces act upon the screw drive eventually destroying the drive. In order to eliminate this drawback, the screw drive can be hydraulically supported while high forces are applied.(DE 101 04 109 A1 and EP 0 760 277 B1) In these solutions a worm gear spindle actuating the screw of the injection unit is supported via a hydraulic cylinder, the piston rod is connected to the worm gear spindle. Such hybrid solutions having an electric drive and a hydraulic support require a comparatively high expenditure in terms of devices and energy. (Dantlgraber,US Patent 7,811,080; 10/12/2010)
Recent US Patents
12/2010
7,811,080
Injection unit
Dantlgraber; of Bosch Rexroth, Germany has developed an electrically driven screw connected to a support which can drive the resin into the mold. (RDC 1/6/2011)