Manufacturing method of core material, manufacturing method of trim material, and core material

摘要

A method of manufacturing an elongated core which is buried in an elongated trim. The method includes, forming slits to a metal plate, which extend in a second direction, at predetermined intervals in a first direction so as to form core pieces between the adjacent slits; and rolling a portion of the metal plate in which the slits are not formed in the second direction to form a rolled portion extending in the first direction, and expanding the slits in the first direction to form spaces, thereby preparing a primary core in which the core pieces and the spaces are alternately provided in the first direction. Additionally, the method includes, supplying the primary core to between a pair of deformed portion forming rollers engaged with each other such that reinforcing defaulted portions extending in the second direction are repetitively formed in the first direction.