METHOD FOR PRODUCING ANNULAR MOLDINGS SUBJECTED TO TENSILE OR PRESSURE LOADING FROM PLASTIC

摘要

The invention relates to methods for producing annular moldings (12) subjected to tensile or pressure loading from plastic by using an injection mold (2) having a main cavity (42), wherein, in addition to the main cavity (42) at least one extra cavity (46) is incorporated in the injection mold (2), wherein the at least one extra cavity (46) is joined to the main cavity (42) by a connecting duct (47). The main cavity (42) is filled with plastic melt in such a way that a flow line (40) is formed in the main cavity (42) in the vicinity of the connecting duct (47) between the at least one extra cavity (46) and the main cavity (42), wherein the cross section of the connecting duct (47) is dimensioned such that during the filling of the main cavity (42), no plastic melt flows into the extra cavity (46). The filling pressure is increased until plastic melt flows into the extra cavity (46); flow taking place through the flow line (40) produced during the filling of the main cavity (42). Subsequently the injection mold (2) is opened and the molding (12) removed.