Machining method, program, machining-program generating program and machining apparatus of press die

A machining apparatus for machining a press die having a pierce cutter with a peripheral profile and a side surface, the press die also having a secondary relief-clearance area recessed inward relative to the profile and side surface of the pierce cutter, the pierce cutter and the secondary relief-clearance area being arranged one behind the other in a piercing direction in which the press die is actuatable to pierce a workpiece when the press die is in a press, the apparatus comprising:

• a three-dimensional drive mechanism including a machining tool and a spindle head for rotatably supporting the machining tool, the three-dimensional drive mechanism relatively moving the spindle head and a press-die material three-dimensionally;
• and a controller for controlling an operation of the three-dimensional drive mechanism, wherein
• the machining tool has a tool body and at least one edge portion provided on an outer circumference of an end of the tool body, the at least one edge portion protruding from the outer circumference of the tool body and being capable of carving while rotating around an axis of the tool body and moving in an axial direction of the tool body, and
• the controller has a unit for executing:
• a relative movement step, in which the machining tool and the press-die material are relatively moved along the profile of the pierce cutter while rotating the machining tool with the axis of the tool body of the machining tool being approximately parallel to the side surface of the pierce cutter;
• and a plunge cutting step for cutting the pierce cutter and the secondary relief-clearance area, in which the machining tool and the press-die material are relatively moved in the axial direction of the tool body along a shape of the pierce cutter and the secondary relief-clearance area in the piercing direction each time the machining tool and the press-die material are relatively moved along the profile of the pierce cutter by a predetermined pitch.