Intelligence Press Brake for Aircraft Skin Bending

Abstract

LVD Company NV and Kawasaki Heavy Industries, ltd. developed the cutting-edge, high performance CNC press brake [1] for high accuracy/precision bending of approx.10m (L) by 2.5m (W) size aircraft skins. Those skin sheets have complex shapes which include mainly machine milled thickness reduction area called pockets, thickness tapers, cutouts for the windows and doors. Due to those characters, the materials have large thickness variation between less than 2 mm and more than 11 mm in a single skin sheet. Here in this paper, the overview of this intelligence press brake equipment and its forming process are described. The materials with complex shapes described above can be bent accurately including material edges with the features of the press brake which are the synchronized material handling system, 210 numbers of variable punches, the special die suitable for the variable punches, the curvature measurement devices, and an automated bending mechanism with curvature feedback /feedforward. In addition, cardboard-like-filler jigs which are used to make thickness variations flat in a traditional bending process and shims to adjust regional press strokes can be eliminated, which reduce significant process time and product quality without worker’s superior skills. As a result, full automation of accurate bending process of aircraft skins have been achieved.