Document Type and Number:
Japanese Patent JPH0581333
Kind Code:
B2
Abstract:
PURPOSE:To improve the forming quality and the forming yield by providing a tapered part having a specified inclination or a projecting circular arc part having an equivalent curvature on the circumferential end part of the top surface of a punch and setting its barrel diameter to exceed a specified rate of the die diameter. CONSTITUTION:The tapered part 4a or the circular arc part 4b inclining to the circumferential side wall 5 of the punch is formed on the circumferential end part of the top surface of the punch 1. In this case, the inclination theta to a vertical line V of the tapered part 4a is controlled to 30-70 degrees. For the circular arc part 4b, the curved surface is changed by a curvature equivalent to its inclination. Further, the barrel diameter D1 of the punch 1 is limited to exceed 90% of the die diameter D2. Hereby, the flow of a stock sheet 20 in the top surface part 2 of the punch 1 can be held favorably in a forming time. Further, the base 20 is deformed uniformly and fully. Accordingly, the forming quality and the forming yield are improved.
Inventors:
SAKAGUCHI MASASHI
YAMANOI TOMOAKI
YAMAMOTO ISAMU
TAKADA SUSUMU
YAMANOI TOMOAKI
YAMAMOTO ISAMU
TAKADA SUSUMU
Application Number:
JP10601588A
Publication Date:
November 12, 1993
Filing Date:
April 27, 1988
Export Citation:
Assignee:
SHOWA ALUMINIUM CO LTD
International Classes:
B21D22/20; B21D24/00; B21D33/00; B29C51/14; (IPC1-7): B21D22/20; B21D24/00; B21D33/00; B29C51/14
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