Tapping method and device, and punch press

摘要

A tapping method includes engaging a front end of a tap with a prepared hole formed in a workpiece. The tap is provided at a tapping tool attached to a rotating mold indexing device that includes a control motor M. The rotating mold indexing device is rotatably provided at a punch press. The tapping method also includes rotating the control motor M positively to rotate the tap positively when the front end of the tap is engaged with the prepared hole. The tapping method also includes stopping positive rotation of the control motor M and rotating the motor reversely, thereby to detach the tap from the prepared hole of the workpiece, when it is detected that the control motor M has rotated a determined number of times or that a predetermined time has elapsed.