PREPARATION OF SPHERICAL SHELL-LIKE METAL PARTS

摘要

PURPOSE:To form a work in the spherical shell-like curved face of high accuracy by expanding an elastic body by applying fluid pressure between the elastic body and lower metal die after forming a flange on the work by the outer periphery of the upper metal die having recessing type curved face and the elastic body. CONSTITUTION:The outer peripheral flange part 15 of a work 1 is formed by pressing the work 1 between the upper die 2 and lower die 3. In this case it is prevented that the work 1 is pulled into the inner part by reducing the air pressure of the upper part air pool 11 with the elastic body film 4 being expanded to the side of the lower die air escaping recessed part 9 with the upper part air pool 11 of the elastic body film 4 of the lower die 3 being compressed. The work 1 is then formed with press to the spherical shell-like curved face 10 of the upper die 2 by its expanding by pushing up the elastic body film 4 with the action of the fluid pressure on the lower die air escaping recessed part 9 from a fluid pressure action port 5.