Effects of lap sheets on the improvement of the formability of metal foil

The improvement of the deep drawability of nickel foil was investigated. The reduction in sheet thickness easily causes defects such as buckling (wrinkling) and fracturing. In order to prevent such defects and to improve the deep drawability of nickel foil, foil–lap blanks, in which thin sheets were lapped over nickel foil, were used in deep-drawing operations. Polyethylene sheets, nylon66 sheets and aluminum sheets were used as lap sheets, i.e., thin sheets for lapping over foil in deep drawing. The effects of lap sheets on the deep drawability were investigated from the viewpoint of the mechanical properties and combination of lap sheets. The deep drawability was improved using aluminum lap sheets and nylon66 lap sheets. Wrinkles on the foil cups were prevented by the lap sheet on the blank-holder side. The combination and types of lap sheets determined the deep drawability of the nickel foil cups.