Precise SMC molding charge weighing method for production of consistent molded products involves cutting layer sections to a set maximum weight and adding material pieces or paste if weight is short

摘要

Single layer sections(24,25) are cut from SMC(sheet molding compound) strip and either used alone or stacked to form a molding charge. Layer sections are cut to a constant shape and/or size so that in each case the set weight of molding material is adapted to the maximum weight/unit area, i.e. mean weight plus weight deviation, of the SMC strip. The material layer or layer stack is then weighed(15) to compare with the desired set weight. Any deficit is corrected by addition of a strand of paste-like resin compound and/or small pieces(30) of the SMC material. The additional material is added while the stack of SMC layers is still on the weighing balance(15) allowing the increasing charge weight to be continuously monitored. When adding small pieces(30) of SMC, the latter are cut from the SMC strip parallel and transverse to the fiber direction in the strip. The small pieces are stored in a closed container(35) in which a solvent saturated atmosphere is maintained. A screw conveyer(36) meters the small pieces out of the container via an opening with a closure flap(37).