PRESS-WORKING METHOD FOR SHEET METAL, DIE THEREFOR, AND FORMED PRODUCT

摘要

A press-working method for a metal plate material uses a die having an upper die and a lower die which have pressing surfaces the outlines of which are determined so that surface irregularities composed of protrusions caused by concentration of a fluid material during press-working and of depressions caused by spreading of the fluid material during the press-working are formed on each of the front and rear sides of the blank. The press-working method heats those contact sections of the dies which make contact with the blank and simultaneously forms the surface irregularities on both sides of the plate material such that the depressions of the irregularities on one side do not correspond to the protrusions of the irregularities on the opposite side. The method can produce in a short time a metal formed product having the surface irregularities on the front and rear sides of the product with the irregularities on each side not corresponding to each other.