Flexible and Inclemental Sheet Metal Bulging Using a Few Spherical Rollers

Abstract

A flexible and incremental sheet metal bulging machine using a few spherical rollers has been developed for the small-batch manufacture of nonsymmetrical shallow shells, and for eliminating the necessity of the forming die and punch. The hand-operated bulging machine performed a wide range of sheet metal shaping of complex shapes, for example, pyramidal shells, shells of the frustum of a pyramid, shallow pans and embossed panels. An approximate calculation method for the distribution of thickness strain and the maximum bulging height of the shell was proposed using the fracture limit from the incremental bulging test with a ball punch and a geometrical plane-strain deformation model. The predictions for the shell of the frustum of a quadrangular pyramid and the shell of the frustum of a right circular cone were in reasonably good agreement with experimental values for the annealed aluminum sheet. © 1993, The Japan Society of Mechanical Engineers. All rights reserved.