A fuel injector with an orifice disc and a method of forming the orifice disc

A fuel injector (100) includes a seat (138), a movable member (122) cooperating with the seat, and an orifice disc (140). The orifice disc includes a member (10) having first (20) and second (40) generally parallel surfaces, and an orifice (30) extending through the member between first and second generally planar surfaces of the member. The orifice is defined by a wall that couples the first and second surfaces. The wall includes first (32A) and second (32B) wall portions. The first wall portion is spaced from the first surface (20) and extends substantially perpendicular to the first and second generally planar surfaces and about the longitudinal axis (A-A) to define a transition perimeter (42). The second wall portion (32B) couples the first wall portion (32A) to the first surface (20) to define a inlet perimeter (44) on the first surface. The inlet perimeter includes a plurality of curved surfaces (35A - 35F) connecting the inlet perimeter (44) and the transition perimeter (42), each of the plurality of curved surfaces being separated from adjacent curved surfaces by a line (38A - 38E) connecting the inlet and transition perimeters in a helical orientation with respect to the orifice axis (200).