In this part that includes a cut end surface consisting of a surface-treated steel sheet that has been cut, the shape of the cut end surface is such that the length of a first shear droop occurring in the sheet thickness direction is at least 0.10 times the sheet thickness of the surface-treated steel sheet, and the length of a second sheer droop occurring in the planar direction is at least 0.45 times the sheet thickness of the surface-treated steel sheet. Furthermore, in the cutting process a die is used for which the clearance between the punch and the die is 1-20% of the plate thickness of the surface-treated steel plate, and the shoulder portion of the die and/or the punch is provided with a radius of curvature of at least 0.12 times the plate thickness of the surface-treated steel plate.

When provisionally blanking a lamination sheet by using a punch for provisional blanking and a counter punch, the displacement of pilot holes located around the lamination sheet is minimized. The progressive die machine (1) comprises a pilot hole punch (72), a punch (9) for provisionally punching an iron core laminate (2) from a strip (W) formed with pilot holes (P), a counter punch (31) provided in a lower die assembly (5) and configured to push the iron core laminate (2) against the punch (9), a stripper plate (13) for separating the strip (W) from the provisional blanking punch after a provisional punching, a punch (10) for completely separating the iron core laminate from the strip. At least a part of the stripper plate (13) associated with the provisionally blanking is not in contact with the strip, and at least a part of an outer peripheral part of the provisionally blanked lamination sheet is formed with a connecting portion (79) connected to the strip.

When provisionally blanking a lamination sheet by using a punch for provisional blanking and a counter punch, the displacement of pilot holes located around the lamination sheet is minimized. The progressive die machine (1) comprises a pilot hole punch (72), a punch (9) for provisionally punching an iron core laminate (2) from a strip (W) formed with pilot holes (P), a counter punch (31) provided in a lower die assembly (5) and configured to push the iron core laminate (2) against the punch (9), a stripper plate (13) for separating the strip (W) from the provisional blanking punch after a provisional punching, a punch (10) for completely separating the iron core laminate from the strip. At least a part of the stripper plate (13) associated with the provisionally blanking is not in contact with the strip, and at least a part of an outer peripheral part of the provisionally blanked lamination sheet is formed with a connecting portion (79) connected to the strip.

A method for manufacturing a metal element includes performing press processing and punching processing on a band plate-shaped metal element material having a constant cross section by a mold with a main punch in contact with a rear surface of the metal element and a counter punch in contact with the front surface thereof. The main punch or the counter punch has protrusion portions which are in contact with at least a part of the ear portion or the body portion to form a recessed portion, and a bulging portion bulging in the longitudinal direction from the radial direction inner edge of ear portions of the metal element or the radial direction outer edge of a body portion thereof, which is formed by the material extruded from the recessed portion by the protrusion portion.

A method for manufacturing a metal element includes performing press processing and punching processing on a band plate-shaped metal element material having a constant cross section by a mold with a main punch in contact with a rear surface of the metal element and a counter punch in contact with the front surface thereof. The main punch or the counter punch has protrusion portions which are in contact with at least a part of the ear portion or the body portion to form a recessed portion, and a bulging portion bulging in the longitudinal direction from the radial direction inner edge of ear portions of the metal element or the radial direction outer edge of a body portion thereof, which is formed by the material extruded from the recessed portion by the protrusion portion.

A lower die has a first lower-die edge extending along the outline shape of a sheet material, and a plurality of second lower-die edges disposed vertically below the first lower-die edge and each extending in a direction traversing an offcut of a sheet base material that is left behind after the sheet material is punched out. An upper die has a first upper-die edge which extends along the first lower-die edge and between which and the first lower-die edge the sheet base material is shorn to punch out the sheet material, and a plurality of second upper-die edges which is provided so as to be protrusible to vertically below the second lower-die edges and between which and the second lower-die edges the offcut is shorn and divided.

A lower die has a first lower-die edge extending along the outline shape of a sheet material, and a plurality of second lower-die edges disposed vertically below the first lower-die edge and each extending in a direction traversing an offcut of a sheet base material that is left behind after the sheet material is punched out. An upper die has a first upper-die edge which extends along the first lower-die edge and between which and the first lower-die edge the sheet base material is shorn to punch out the sheet material, and a plurality of second upper-die edges which is provided so as to be protrusible to vertically below the second lower-die edges and between which and the second lower-die edges the offcut is shorn and divided.

A machining surface of a die are provided with a pair of inclined surfaces facing each other across a gap and a flat surface interposed therebetween. Each inclined surface includes an inner end portion on a side near the flat surface and an outer end portion on a side farther away from the flat surface. The molding method includes a mounting step of mounting the metal sheet on the die to span both inclined surfaces, and a pressing step of forming a reduced-thickness portion by pressing the metal sheet between the punch and the inclined surfaces of the die. The pressing step includes setting a bottom dead center of the punch to maintain a gap formed between the inner end portion and a surface of the metal sheet facing the inner end portion.

A machining surface of a die are provided with a pair of inclined surfaces facing each other across a gap and a flat surface interposed therebetween. Each inclined surface includes an inner end portion on a side near the flat surface and an outer end portion on a side farther away from the flat surface. The molding method includes a mounting step of mounting the metal sheet on the die to span both inclined surfaces, and a pressing step of forming a reduced-thickness portion by pressing the metal sheet between the punch and the inclined surfaces of the die. The pressing step includes setting a bottom dead center of the punch to maintain a gap formed between the inner end portion and a surface of the metal sheet facing the inner end portion.

Provided is an adjustment device of a punching device which punches a workpiece placed on a die having a punching die with a punch so that the workpiece is punched into a predetermined shape. The adjustment device of the punching device includes a first drive mechanism that moves the punch or the die in a direction orthogonal to a punching direction, and a controller connected to the first drive mechanism in a communicable manner. The controller brings the punch and the die into contact with each other by moving the punch or the die in four orthogonal directions in a plane perpendicular to the punching direction from an initial position where the punch is inserted into the punching die. Based on a distance between the initial position and each contact position in the four directions, the controller causes the first drive mechanism to move the punch or the die to a center position where a central axis of the punch and a central axis of the die are aligned with other.