Production manner null of koiningudoro -

摘要

PURPOSE:To optimize the wall thickness of a collar by executing in advance coining working, working a prepared hole in a thin plate base material which has formed an annular metallic mass in the periphery of a scheduled diameter of the prepared hole, and thereafter, bringing the metallic mass part to ironing working, and forming a fin collar part. CONSTITUTION:A cavity 90 is formed by pressing a base material 100 by a coining punch 150 and a coining die 160, and bringing the base material to a plastic movement. Subsequently,, the cavity part 90 which has become a foil state is pierced, and next, simultaneously with burring, a side wall 112 of a collar part is formed by ironing working. By manufacturing the titled fin by such a method, a decrease of wall thickness of the side wall of the fin collar part is prevented, the contact pressure to a pipe can be improved, and the heat transmission property can be improved.