SQUARE SHELL DRAWING CHARACTERISTICS OF ALUMINUM-ALLOY SHEET A5182-O

Deep-drawing experiments on aluminum alloy sheet A5182-O of 0.48 mm thickness have been conducted using square punches with the geometrical ratios r(c)/l = 0.1, 0.15, 0.238, 0.25, and 0.5 (l is the side length of the punch, r(c) is the corner radius of the horizontal section of the punch). Two types of fracture, punch-profile fracture and wall breakage, were found to limit the drawable heights, and the map which clarifies the relationship between blank shapes and the types of fracture was generated for all the punches. The optimum blank shape to give the deepest shell was determined also for each punch shape. The deep-drawing conditions which affect the wall breakage were discussed. The wall breakage was found to be restrained by preventing the blank-holding force from concentrating on the corner portions in the flange; in this case by sticking strips of stainless-steel tape onto the blank-holding plate, in front of the sides of the die cavity.