ダイス穴周辺部圧縮を伴う液圧張出加工によるフランジ付き深いアルミニウム容器の作製 Production of aluminum tall container with flange by hydraulic bulging with compression of surrounding material
Bulging process is suitable to produce cups with wide flange because of keeping the contour shape of blank sheet unchanged. On the other hand, it is difficult to form tall cups by conventional bulging because, at punch shoulder, thickness of metal sheet becomes much smaller than other portions and it results in a quick breakage there. When the way to decrease the thickness of a sheet metal during the process approaches more to the uniform one, it becomes possible to form cups with both of wide flange and large height. In this study, a new bulging process combined with ironing was proposed in order to form tall cups with wide flange. In this new method, as in the conventional hydraulic bulging method, hydraulic pressure was used to deform metal sheet uniformly. In this hydraulic bulging, compression around die hole by a metal ring assisted the hydraulic pressure to put material into the die-hole. In addition to that, a counter metal punch was used to prevent the material on the head of bulged portion from locally thinning. Furthermore, following ironing makes it possible to decrease thickness of sidewall. In order to clarify the effectiveness of this method, differences of the configuration and the thickness strain distribution between products formed by conventional and new methods were investigated. Finally, it was confirmed that this method make it possible to produce a cup four times as tall as conventional one.
軽金属 58(2), 47-53, 2008-02-28
The Japan Institute of Light Metals