| 摘要 |
PROBLEM TO BE SOLVED: To manufacture an Al casing having a low stepped part of high quality which is used for the casing for an appliance such as a digital video camera. SOLUTION: An aluminum blank 1 is drawn into the casing 3 having low side walls 2, parts of a top plate 4 which are formed into a low stepped part 5 pressed in the thickness direction while other parts than the low stepped part 5 of the top plate 4 are drawn into a high stepped part 6. Since the parts other than the parts forming the low stepped part 5 of the casing 3 having the low side walls 2 are drawn into the high stepped part 6, flange elongation is avoided, and cracks at a stepped part 8 is prevented. In addition, since the drawing is performed while the parts forming the low stepped part 5 is pressed in the thickness direction, outflow of the material to the stepped part 8 is prevented, and wrinkles at the low stepped part 5 can be prevented.
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