Molding apparatus (20, 20', 20", 20′′′) for molding an opening device onto a web of packaging material comprising: - at least one mold unit (21, 44, 45) couplable to the web of packaging material; and - an injection device (22, 22′′′) configured to inject a molten polymer into the mold unit (21, 44, 45); wherein the injection device (22, 22′′′) comprises at least: - a cavity configured to receive the molten polymer; - an inlet configured to allow for introduction of the molten polymer into the cavity; characterized in that the injection device (22, 22′′′) further comprises: - a first outlet configured to allow for an outflow of a first portion of the molten polymer from the cavity; - a first valve element (27, 29, 53) configured to selectively open and close the first outlet; - a second outlet configured to allow for an outflow of a second portion of the molten polymer from the cavity; - a second valve element (27, 29, 53) configured to selectively open and close the second outlet; and - a pressurizing unit being in fluidic connection with the cavity and configured to pressurize the molten polymer within the cavity. - at least one mold unit (21, 44, 45) couplable to the web of packaging material; and - an injection device (22, 22′′′) configured to inject a molten polymer into the mold unit (21, 44, 45); wherein the injection device (22, 22′′′) comprises at least: - a cavity configured to receive the molten polymer; - an inlet configured to allow for introduction of the molten polymer into the cavity; characterized in that the injection device (22, 22′′′) further comprises: - a first outlet configured to allow for an outflow of a first portion of the molten polymer from the cavity; - a first valve element (27, 29, 53) configured to selectively open and close the first outlet; - a second outlet configured to allow for an outflow of a second portion of the molten polymer from the cavity; - a second valve element (27, 29, 53) configured to selectively open and close the second outlet; and - a pressurizing unit being in fluidic connection with the cavity and configured to pressurize the molten polymer within the cavity. - a cavity configured to receive the molten polymer; - an inlet configured to allow for introduction of the molten polymer into the cavity; characterized in that the injection device (22, 22′′′) further comprises: - a first outlet configured to allow for an outflow of a first portion of the molten polymer from the cavity; - a first valve element (27, 29, 53) configured to selectively open and close the first outlet; - a second outlet configured to allow for an outflow of a second portion of the molten polymer from the cavity; - a second valve element (27, 29, 53) configured to selectively open and close the second outlet; and - a pressurizing unit being in fluidic connection with the cavity and configured to pressurize the molten polymer within the cavity. - a first outlet configured to allow for an outflow of a first portion of the molten polymer from the cavity; - a first valve element (27, 29, 53) configured to selectively open and close the first outlet; - a second outlet configured to allow for an outflow of a second portion of the molten polymer from the cavity; - a second valve element (27, 29, 53) configured to selectively open and close the second outlet; and - a pressurizing unit being in fluidic connection with the cavity and configured to pressurize the molten polymer within the cavity.