Patent ID: 6807838
Filing Date: 2004-10-26
Classification: B21D

Abstract:
A press die comprising:a first die having a concave part, said concave part having an opening, the peripheral surface of the opening functioning as a first blank pressing face; a second die having a convex part, said second die forming a blank into a desired form in cooperation with said concave part; and a blank holder having a second blank pressing face, said blank holder working in such a way that said first blank pressing face and said second blank pressing face hold the blank between them while permitting it to flow into said concave part during pressing, wherein at least either of said first blank pressing face and said second blank pressing face has a roughened surface with a plurality of striated projections which are formed around the entire circumference of the edge of the opening of said concave part, and entirely extending in a direction inclined in a range of âˆ’25Â° to +25Â° toward the circumferential direction of the edge of the opening of said concave part, and wherein said roughened surface has a surface roughness (Ra) of 0.02-60 &mgr;m measured in a direction perpendicular to the circumferential direction of the edge of the opening of said concave part.