Abstract: The invention relates to apparatus and methods for manufacturing a bent product by press bending a malleable material. The bent product is bent along the lengthwise axis and has a bottom wall and at least one sidewall in cross section. The apparatus preferably includes a die having within its surface a recess. The recess is bent along the lengthwise axis. The apparatus also includes a punch that may be inserted into the recess of the die. The die and the punch substantially correspond to each other such that the die and the punch include a first portion having a first bend radius corresponding to a lengthwise bend in the bent product and a second portion having a second bend radius corresponding to a linear region of the bend product. If the first bend radius is smaller than the second bend radius, chamfered faces formed in the die and punch are shallower and narrower in the first bend radius than the second bend radius.

Abstract: In a method and apparatus for press bending a metal plate, a punch is inserted into a recess of a die to bend a plate. The punch has a first edge formed away from a die and a second edge formed near the die. A corner of the recess of the die opposed to the punch is chamfered. The chamfered face has a third edge formed at the border of the top side of the die at the chamfered recess. In a first half of the press bending, the plate is bent with the first and third edges serving as lines of contact. Subsequently, the plate is further bent with the second edge serving as a line of contact. A portion of the punch between the first and second edges is held in a non-contact state with the plate throughout steps of press bending the plate.