Patent ID: 6656603
Filing Date: 2003-12-02
Classification: B21D,B23K,B64C,Y10T

Abstract:
A multisheet metal structure obtainable by the steps of:(a) assembling multiple sheets of an alloy suitable for superplastic forming in a vertical stack; (b) clamping the sheets together at a drill point and welding the sheets together around the periphery of a region in which a hole is to be drilled sequentially through the stack of sheets; (c) drilling a hole sequentially through said sheets in the region within the welded periphery so that the weld bounds the hole; (d) inserting a sleeve into the hole adjacent the weld, the sleeve having the same height as the sandwich structure at the drill point after the sheets are expanded; (e) inserting the sheets with the sleeve into a die having an internal cavity, the cavity having a shape the same as the intended design shape of the expanded sandwich structure; and (f) superplastically expanding the sheets in the die cavity to form the expanded sandwich structure and to cause the welded and drilled sheets to contact the sleeve along the length of the sleeve to define a reinforced hole, being a sealed opening, through the expanded sandwich structure.