Method for manufacturing figure-T shaped metal part and figure-T shaped metal part

A method for manufacturing a Figure-T shaped metal part,

• wherein the method comprises:
• determining a desired length of a cutting plane in a thickness direction of a metal plate having any of a rectangular, polygonal, or elliptical shape, or in a diameter direction of a metal rod having a cross-section of any of a circular, elliptical, rectangular, or polygonal shape;
• applying a slitting punch or a cleaving punch on a split-desired end of the metal plate, or the metal rod, on a boundary created by the cutting plane;
• securing the metal plate by pinching both sides of a split-desired portion thereof with a clamping device, or securing the metal rod by pinching at least two opposite-facing portions on a periphery thereof with a clamping device;
• splitting and advancing the splitting by pressing a slitting punch or a cleaving punch against a cleft of a split for repeatedly two or more times until a split length reaches a specified extent;
• folding an edge portion of one side or the both sides in the split end of the metal plate, or the metal rod, to a center;
• undergoing a press-forming or crimping so that a folded portion becomes flat,
• wherein, in advance of each time of each subsequent splitting operation of the two or more times, a position of at least one side of the clamping device that pinches both sides of the metal plate in a prior operation of securing or that pinches at least two opposite-facing portions on a periphery of the metal rod in the prior operation of securing, is moved along the metal plate or the metal rod in advance by a stroke-corresponding to a distance from a position of the cleft of the split toward a distal end of a split-desired position, followed by securing of the metal plate by pinching both sides thereof with the clamping device, or by securing of the metal rod by pinching at least two opposite-facing portions on the periphery thereof with the clamping device;
• and
• thereby the metal plate, or the metal rod, is partially split in a longitudinal direction along the cutting plane,
• wherein, in each interval between splitting operations of the two or more times, pressing of the splitting punch or the cleaving punch is suspended and the splitting punch or the cleaving punch is moved back to a relatively opposite direction,
• wherein, on both sides in a case of the splitting punch or on one side in a case of the cleaving punch, a cutting edge is given a tapering shape having at least two taper portions of different angles or curvatures so that the taper portion of the side close to a tip end of the cutting edge has a smaller inclination angle from a horizontal line based on the definition that the inclination of the horizontal line is zero, or a smaller curvature than that of the taper on the side apart from the tip end of the cutting edge.