Apparatus for molding flat plastics products used for manufacturing smart cards has a holding zone which is filled with molten material by a retracting piston without pressure and then forced by the piston into the mold

摘要

Apparatus for molding flat plastics products has a holding zone for the molten mass which is filled by a retracting piston without pressure. The molten mass is then forced by the piston into the mold For the molding of plastics products, the piston is at the first dead point at the start of the injection process, where the surface of the piston is flush with the edge of the holding zone and the mold wall, so that a small volume of the molten molding material enters the molding zone directly. The piston slides within its cylinder to give a continuous increase in the volume capacity of the holding zone, so that it is filled with the molten mass without pressure, until the piston is at the second dead point, and the molten mass feed is halted. The piston is returned to the first dead point, to force the molten mass in the holding zone into the mold, to fill it completely, and the piston is held at the first dead point position. An Independent claim is included for an apparatus with a die (S) rigidly bonded mechanically to the molten mass preparation station (E). The die (S) passes through a bush as a component of the first mold plate (PF1), through two openings leading directly into the mold interior (KV). The die (S) has a limit stop (M) where the die (S) in the leading position is flush with the edge of the first opening. Preferred Features: The die (S) is of a material (WS) with thermal conductivity, at least at the free end. The die (S) has a heat exchanger (KS), in a coolant circuit. The heat exchanger (KS) has a thermal coupling with the die (S), at least at the end surface. The coolant circuit is controlled. The second mold plate (PF2) is of thermal conductive material (WF) at least at the zone facing the second opening of the bush. The second mold plate (PF2) has a heat exchanger (KF), in a controlled coolant circuit, with a thermal coupling to the second mold plate (PF2) at least at the zone of thermal conductive material (WF). The limit stop (M) is a cap nut on a shaft at the outlet (ED) of the molten mass preparation station (E). The second opening of the bush is closed mechanically, when the die (S) is in the rear position. An assembly can have a number of dies (S) and mold structures, mounted on a beam The beam has a controlled heater with a heating channel. The beam acts as the limit stop for the movements of the dies. The heating channel can be in a star layout, to connect the outlet (ED) of the molten mass preparation station (E) with the die channels.