アルミニウム合金薄板のフランジ成形におけるスプリングバックとウェブの反り Springback and warp of web in flanging of aluminum alloy sheets
The springback of bending at the die shoulder and the warp of web are discussed experimentally for the products formed by shrink, stretch and straight flanging of aluminum alloy sheets. The springback decreases with the decrease in die profile radius and this tendency is remarkable for larger flange height. When the die shoulder radius becomes large, the springback also becomes large. The springback angle correlates with the proof stress of sheet. The web of products warps downward for shrink flanging and upward for stretch flanging, though the web doesn't warp in case of straight flanging. The height of warp changes not monotonically but having a extreme value when the die profile radius decreases and finally the direction of warp turns to the opposite side. This phenomenon is explained by an analysis in which the warp is generated by both elastic recovery of flange and springback of die shoulder bending. The warp is decreased by reduction of flange height and it increases with increasing die shoulder radius in case of shrink flanging, while decreases in case of stretch flanging.The height of warp also correlates with the proof stress of sheet.
軽金属 48(7), 317-322, 1998-07
The Japan Institute of Light Metals