An injection-molding method for selectively manufacturing molded parts with and without a breakthrough is disclosed. A molded part with a breakthrough is manufactured by positioning a mold core in a mold cavity, whereas a molded part without breakthrough is manufactured by removing the mold core at least partly from the mold cavity. The mold cavity delimited by a nozzle-side mold platen and an ejector-side mold platen. The mold core is movable relative to at least one of the mold platens, in particularly the nozzle-side mold platen, in an advance direction, where the mold core is closer to the nozzle-side mold platen and an opposite withdrawal direction.At least one protective measure is provided for protecting the inner surface facing the mold cavity of the respective mold platen, in particularly the nozzle-side mold platen, from adverse mechanical effects during movement of the mold core in the advance direction.