ストレッチドロー法による円筒成形に関する研究 : 第2報, 2段成形における工程の適切化に関する実験的検討

概要

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Double stretch-drawing process is studied experimentally within the scope of the best or better combination of 1st and 2nd drawing ratios in which the 2nd punch diameter is fixed. It is concluded that the largest total limiting drawing ratio (= initial blank diameter BD divided by the 2nd punch diameter) is achieved when the smallest 1st drawing ratio and the largest 2nd drawing ratio are adopted, both for the double stretch-drawing and the usual double deep-drawing processes. Then the deepest cup can be formed as well. The deepest cup can be formed by double stretch-drawing from smaller limiting BD, applying an appropriately small die-profile radius. However, when we wish to form the deepest cup from a specified BD (not necessarily its limit), or do we to select the smallest BD for a specified cup depth (again not necessarily its limit), this rule is not valid. For the medium size of BD, the best choice of combination of 1st and 2nd drawing ratios exists other than the rule mentioned above. It is emphasized that the best profit of stretch-drawing can be obtained in this region from the view point of material conservation.
社団法人日本機械学会の論文
1999-11-25