Provided is a press-forming method including three steps for preventing spring-back in a hat-shaped cross section shape of a final formed article. In the first step, from a blank, a preformed article in a first form is obtained, the preformed article including a top surface, left and right vertical walls, and left and right tapered portions extending outward from lower ends of the left and right vertical walls, respectively, of a final formed article having a hat-shaped cross section. In the second step, the compression can be applied to the entirety of the top surface, the left and right vertical walls, and the left and right flanges of the final formed article having the hat-shaped cross section, whereby the spring-back can be sufficiently prevented. In the third step, obtain the final formed article having the hat-shaped cross section.

Provided is a press-forming method including three steps for preventing spring-back in a hat-shaped cross section shape of a final formed article. In the first step, from a blank, a preformed article in a first form is obtained, the preformed article including a top surface, left and right vertical walls, and left and right tapered portions extending outward from lower ends of the left and right vertical walls, respectively, of a final formed article having a hat-shaped cross section. In the second step, the compression can be applied to the entirety of the top surface, the left and right vertical walls, and the left and right flanges of the final formed article having the hat-shaped cross section, whereby the spring-back can be sufficiently prevented. In the third step, obtain the final formed article having the hat-shaped cross section.

A method for manufacturing a press molded product includes forming a plurality of corner portions in a pressed portion of a pressed member, providing the pressed member between a first die and a second die, and press molding the pressed portion to decrease a height of the pressed portion. The press molding includes forming a pair of first bent portions in the pressed portion by means of the corner portions, the pair of first bent portions being bent to protrude toward the second die, forming a second bent portion in the pressed portion by means of the corner portions while holding the pair of first bent portions by a pair of holding portions, the second bent portion being bent to protrude toward the first die from a position between the pair of first bent portions, and pressing and deforming the second bent portion.

A method for manufacturing a press molded product includes forming a plurality of corner portions in a pressed portion of a pressed member, providing the pressed member between a first die and a second die, and press molding the pressed portion to decrease a height of the pressed portion. The press molding includes forming a pair of first bent portions in the pressed portion by means of the corner portions, the pair of first bent portions being bent to protrude toward the second die, forming a second bent portion in the pressed portion by means of the corner portions while holding the pair of first bent portions by a pair of holding portions, the second bent portion being bent to protrude toward the first die from a position between the pair of first bent portions, and pressing and deforming the second bent portion.

A processing method for a metal plate includes a curve surface forming recess forming step, a protruding step, and a shaping and dividing step. In the curve surface forming recess forming step, a recess is formed in the metal plate, the recess having an outer periphery forming a curve surface, a side portion formed in a frustum, and a bottom portion being round. In the protruding step, a portion of the recess from the bottom portion to the side portion is protruded toward an inside of the recess, and the side portion of the recess is formed to be close to a center of the recess. In the shaping and dividing step, the protruded portion and the outer periphery of the recess are shaped so that the recess is divided into a group of the plural recess portions adjacent to each other.

A processing method for a metal plate includes a curve surface forming recess forming step, a protruding step, and a shaping and dividing step. In the curve surface forming recess forming step, a recess is formed in the metal plate, the recess having an outer periphery forming a curve surface, a side portion formed in a frustum, and a bottom portion being round. In the protruding step, a portion of the recess from the bottom portion to the side portion is protruded toward an inside of the recess, and the side portion of the recess is formed to be close to a center of the recess. In the shaping and dividing step, the protruded portion and the outer periphery of the recess are shaped so that the recess is divided into a group of the plural recess portions adjacent to each other.

A method of forming a metal sheet into a target shape by press-forming, such that the metal sheet is formed into an intermediate shape that is different from the target shape and then the target shape is formed from the intermediate shape, the method includes: when forming the intermediate shape from the metal sheet, forming the intermediate shape by forming a first region including at least a portion at which a ratio of sheet thickness reduction from the metal sheet is larger when the target shape is formed via the intermediate shape than when the target shape is formed directly from the metal sheet.

A method of forming a metal sheet into a target shape by press-forming, such that the metal sheet is formed into an intermediate shape that is different from the target shape and then the target shape is formed from the intermediate shape, the method includes: when forming the intermediate shape from the metal sheet, forming the intermediate shape by forming a first region including at least a portion at which a ratio of sheet thickness reduction from the metal sheet is larger when the target shape is formed via the intermediate shape than when the target shape is formed directly from the metal sheet.

A domer station having a domer assembly, a housing assembly, and a stacked piston assembly is provided. The domer assembly is movably disposed within a domer body passage located in the housing assembly and structured to move between a forward, first position and a retracted, second position. The stacked piston assembly includes a plurality of pistons, preferably three pistons, disposed in series and a pressure supply. The pistons are disposed behind the domer in pressure chambers. The pistons have a constant pressure applied thereto and are biased towards the domer. The pistons are, however, each restrained by a stop and do not contact, or operatively engage, the domer when the domer is in the domer first position.

A domer station having a domer assembly, a housing assembly, and a stacked piston assembly is provided. The domer assembly is movably disposed within a domer body passage located in the housing assembly and structured to move between a forward, first position and a retracted, second position. The stacked piston assembly includes a plurality of pistons, preferably three pistons, disposed in series and a pressure supply. The pistons are disposed behind the domer in pressure chambers. The pistons have a constant pressure applied thereto and are biased towards the domer. The pistons are, however, each restrained by a stop and do not contact, or operatively engage, the domer when the domer is in the domer first position.