Method and apparatus for numerically controlled, in at least two steps dieless sheet metal forming

摘要

In order to provide a method and apparatus for forming a sheet metal, in which a three-dimensional product such as a prototype for commercialized press-forming can be formed in short time without limitations as to the shape and with high accuracy, preventing body wrinkles or reduction of the sheet thickness,
a process of: performing drawing-forming to a predetermine height by pushing the forming punch (2) having a desired shape in the sheet thickness direction with the edges of the blank workpiece (W) being clamped; performing shape-forming with the shaping tool (4d) in the opposite side to the forming punch (2) by increasing a clamping pressure to lock movement of a material with the forming punch (2) being pushed; performing drawing-forming again by decreasing the clamping pressure and raising the forming punch (2) by a desired height; and performing shape-forming with the shaping tool (4d) by increasing the clamping pressure to lock movement of a material, is repeated at least once.