HOLLOW PART FORMING METHOD Russian patent published in 1997 - IPC

FIELD: plastic metal working, namely, drawing high hollow parts from sheet blanks. SUBSTANCE: method comprises steps of drawing square box with trimmed angular portions from square blank; drawing hollow cylindrical part from said square box. First drawing step is performed at constrained thinning of blank wall in angular portions of said box until thickness , where S*00O -initial thickness of blank, L*003 - dimension of initial square blank along diagonal after trimming its angles; a - length of side of initial square blank; b - width of said box after first drawing operation; R - rounding radius of angular portion, R= (0.28-0.33)b; H - height of box after first drawing operation. EFFECT: minimization of metal losses at trimming end of parts. 2 dwg