HYDRAULIC PUNCHING METHOD FOR CYLINDRICAL MEMBER

摘要

PROBLEM TO BE SOLVED: To provide a hydraulic punching method for a cylindrical member by which highly accurate and economical punching is carried out in the same stage as hydraulic forming. SOLUTION: In the punching method performed with a punching punch 1 while pressurizing a liquid in the stage of the hydraulic forming by which the cylindrical member 11 is formed into a prescribed shape by pressurizing the liquid filled in the inside of the cylindrical member 11, this method has a punching operation which is performed by advancing the punching punch 1 after once making the pressure of the liquid in the state of low pressure and hole correcting operation which is performed by retreating the punching punch 1 while increasing the pressure of the liquid or after increasing it and the punching operation and hole correcting operation are performed at the same time as the hydraulic forming of the cylindrical member 11 or successively.