Method of punching a punch guide hole in a blank holder of a punch assembly a punch assembly and a blank holder

摘要

There is provided a method comprising a process of lightly fitting a distal end portion of a projecting portion 25 of a blank holder 23 into a fitting groove 19 formed in a punch guide 5 so as to be momentarily held therein; and a process of fitting the projecting portion 25 of the blank holder 23 into the fitting groove 19 while punching a punch guide hole 23G in the blank holder 23 when a punching portion 7 of a punch body 9 of a punch assembly 1 is lowered for pressing the blank holder 23 against a die D so that the punch guide 5 descends. In the punch assembly 1 constructed in a manner that the punch body 9 is vertically movably housed in a punch guide 5, and the blank holder 23 is removably fitted into the fitting groove formed in the punch guide 5, the punch guide 5 and the blank holder 23 are formed with an inclined plane 5S and an inclined plane 23S at part of an outer peripheral face on the lower end portion of the punch guide 5 or part of an upper face of a flange of the blank holder 23, respectively.