Method of and apparatus for sprueless molding

摘要

In a method of and an appratus for molding a plastic, pellet type raw material is supplied from the suppy tube (5). A predetermined quantity of the supplied material is then fed by the feed screw (6a) in the feed cylinder (6) into the main cylinder (8) through the connecting channel (8a). The material is heated and molten by a heater provided in the main cylinder (8). The molten material is fed by the main screw (8b) through the injection nozzle (9) into the cavity (12) formed by the mold (2). The sprue (4a) and/or runner is separated by the pusher (16) from the formed plasitcs (4) and the substrate (4) is separated from the mold (2). The separated sprue (4a) and/or runner is collected by the funnel (17) and sucked by the vacuum pump 21 together with the material dust being caused by pushing the sprue (4a) out from the subtrate (4) remaining in the mold (2) so that the sprue (4a) can be fed back into the material flow especially between the feed cylinder (6) and the main cylinder (8) and the material dust can be filtered out.