METHOD AND DEVICE TO MANUFACTURE T-SHAPE HOLLOW BODY OR HOLLOW BODY WHICH IS EQUIPPED WITH AT LEAST ONE DOME-FORM

摘要

PROBLEM TO BE SOLVED: To simplify the manufacturing process, and to reduce the manufacturing cost by swelling a dome with higher internal pressure than the maximum internal pressure to manufacture the dome in manufacturing a T-shaped hollow body or a hollow body provided with at least one dome-shaped branched part. SOLUTION: A cutting edge 13 is not brought into contact with a swollen material of a dome 6 of a hollow body to be formed during the deformation with the maximum manufacturing internal pressure Pi1max . When the dome is completed, the internal pressure is increased up to Pi2, and the material of the dome 6 is filled to the cutting edge 13. A movable radius part 15a is reduced in size to a residual radius part 15b, and the cutting edge 13 is cut into a dome cap 9. When a corresponding holder 8 is fed, the dome cap 9 is finally and completely detached. When the corresponding holder 8 is further fed, it is advanced into the dome 6, and presses off an excess part 16 expanded inwardly in its diameter determining raised part 11 to totally smooth an inner wall 17 of the dome 6, and to determine the diameter.