| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for working a hole, a method for burring, and a punch die capable of reducing or preventing the clinging of shavings to the outer periphery of the punch die. SOLUTION: A method for working holes comprises a hole forming operation for forming a hole 60 penetrating a metal plate member 6 in the depth direction and a machining operation for advancing a punch die 2 into the hole 60 in the metal plate member 6 to shave off the periphery of the hole in the plate-like member by means of the die surface of a punch die 2 resulting in forming a machined surface in sequence. The machining operation comprises a first machining operation for shaving off a part of the periphery of the hole with a second die surface 22 so as to be discontinuous in the circumferential direction of the hole 60 while extending along the circumferential direction of the hole 60 in the plate-like member 6, and a second machining operation for shaving off the remaining part of the periphery of the hole 60 with a third die surface 24. A machined surface 61 extending circularly in the circumferential direction of the hole 60 in the plate-like member 6 is formed by means of the first and second machining operation.
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