Abstract: In order to join a first plate element such as a rear quarter panel of an automobile and a second plate element such as a roof panel together, an edge portion of the first plate element is provided with a joggled portion. The joggled portion is formed integrally with a general portion of the first plate element by way of a shoulder. The joggled portion includes an offset reinforcing portion having a band-shaped recess along the shoulder. A major portion lying closer to the terminal edge of the joggled portion than the reinforcing portion includes a joining surface to which an edge portion of the second plate element is joined in a face-to-face contact in such a manner that a gap is defined between an terminal edge of the edge portion and the shoulder. A welding material is built up into the recess of the reinforcing portion through the gap to thereby join the first and second plate elements together.

Abstract: In order to join a first plate element such as a rear quarter panel of an automobile and a second plate element such as a roof panel together, an edge portion of the first plate element is provided with a joggled portion. The joggled portion is formed integrally with a general portion of the first plate element by way of a shoulder. The joggled portion includes an offset reinforcing portion having a band-shaped recess along the shoulder. A major portion lying closer to the terminal edge of the joggled portion than the reinforcing portion includes a joining surface to which an edge portion of the second plate element is joined in a face-to-face contact in such a manner that a gap is defined between an terminal edge of the edge portion and the shoulder. A welding material is built up into the recess of the reinforcing portion through the gap to thereby join the first and second plate elements together.

Abstract: A press die for piercing operation comprises an upper die movable toward and away from a lower die. When the upper die is moved toward the lower die, a pad interposed between the two dies is forced against the lower die to hold a workpiece sheet against the lower die. The pad has a hole in which a tubular elastic member is fitted. The elastic member has a hole for passing a punch having a projecting tip. The lower die has a hollow bore which is in confrontation with the projecting tip. When the upper die is moved toward the lower die on which the workpiece is laid, the pad holds the workpiece and the upper die drives the punch so that the projecting tip of the punch pierces the workpiece by being driven into the hollow bore. The elastic member is deformable and allows the punch to shift laterally so that the projecting tip and the hollow bore are in accurate coaxial alignment.

Abstract: A press die assembly is efficiently produced by: fabricating a press die pattern having therein grooves extending along concave corner portions thereof corresponding to concave corner portions of a product forming surface in the die of the press die assembly; fabricating a cast blank of the die by a full-mold method by using the press die pattern; and machining and finishing the product forming surface of the cast blank by utilizing the grooves as clearance space for the machining and finishing tools to obtain the finished die. In the press forming operation of the press die assembly, the grooves permit the sheet blank being press formed to slip thereby to eliminate local stretching, whereby high-quality pressed products are obtained. The grooves enables an easy machining by a tool.

Abstract: A press die assembly is efficiently produced by: fabricating a press die pattern having therein grooves extending along concave corner portions thereof corresponding to concave corner portions of a product forming surface in the die of the press die assembly; fabricating a cast blank of the die by a full-mold method by using the press die pattern; and machining and finishing the product forming surface of the cast blank by utilizing the grooves as clearance space for the machining and finishing tools to obtain the finished die. In the press forming operation of the press die assembly, the grooves permit the sheet blank being press formed to slip thereby to eliminate local stretching, whereby high-quality pressed products are obtained. The grooves enables an easy machining by a tool.

Abstract: A method of machining a press die. A scabrous surface is formed by cutting a die block of the press die. Then, part of the scabrous surface of the die block is ground to form a smooth surface. The part contacts with a work from an initial stage of press working of the work by the press die. Finally, a friction resistant material layer is coated over the smooth surface.