Patent ID: 8567063

Claim:
A machining method for forming an orifice in a curved surface portion or a slant surface portion in a fuel injection valve by operating a punch in an axial direction inclined relative to a normal direction perpendicular to a tangent plane of the curved surface portion or relative to a normal direction perpendicular to the slant surface of the slant surface portion and forming the orifice by press-working, the machining method comprising: a first step of operating the punch along an axis pre-shifted in parallel in advance from an orifice axis and pressing an orifice plate to form a recess therein; a second step, after the first step, of shifting the axis of the punch used in the first step to the position of the orifice axis and operating the punch at the position of the orifice axis to form a recess in a bottom of the recess formed in the first step, the recess formed in the second step being deeper than the recess formed in the first step; and a third step of forming an orifice in a bottom of the recess formed in the second step.