Abstract: Two kinds of failure during tapered shell drawing, the compression buckling of sidewall and the fractures in the smaller end, are investigated. During tapered shell drawing along the sheet it is hard for the sheet to sustain compression and the sheet contracts latitudinally and stretches longitudinally. Taken these into considerations, the maximum relative drawing depth is worked out to get a tapered shell drawpiece without latitudinal buckling in the sidewall according to the longitudinally maximum tensile stress the tapered shell drawpiece can endure and acquire the maximum relative drawing depth that can avoid fractures in the dangerous areas of the smaller end. Consequently, the forming condition of tapered shell drawing and the characteristc equation and eigenvalue of relative cone radius is established. Good agreement is found between the theoretical calculations and the results from the experiment that uses SPCC deep drawing sheet and S754 Aluminum alloy sheet as workpieces.

Key words: Drawing, Plastic processing, Punching