To manufacture burring worked part having a flange part extended from a metallic sheet by minimizing the bent part on the inside of the root (outside of bending) without generating buckling on the outside of the root of the flange part.
The flange part 1b having a tapered outer periphery surface, which is extended from the metallic sheet 1a and whose outer diameter is gradually reduced toward the tip is formed by burring and is made a semi-manufactured product. A punch P having an outside diameter which is approximately same as the inside diameter of the tip of the flange part is arranged movably on the same axis as the axis of the flange part and also a die D having the inside diameter which is approximately same as the outside diameter at the tip of the flange part of the working target is arranged. The flange part of the working target is formed by relatively driving the punch and the die to the metallic sheet so that the inner peripheral surface of the die is moved to the metallic sheet while pressing the tapered outer peripheral surface of the semi-manufactured product from the tip of the flange part of the semi-manufactured product in the state where the punch is present in the flange part of the semi-manufactured product.
WATABE TETSUYA
KAGITANI JIRO
