METHOD OF SELECTING THICKNESS AND MATERIAL OF BLANK Russian patent published in 1997 - IPC

FIELD: plastic metal working, namely, selection of thickness and material of blanks for forming body parts of motor vehicle. SUBSTANCE: selection of thickness and material of blank is realized by determining ductility factor according to diagram of limit deformations in critical points on local portions of parts at drawing process. Drawing is performed by stretching blank around pattern at several steps. At first step blank is mounted in tensioning machine. At second step blank is drawn according to recesses of master pattern until moment of starting corrugating process and formed corrugations are straightened. Then blank is mounted on master pattern and it is drawn by means of mandrel. In order to prevent formation of corrugations, impacts are applied by mandrel alternatively at both sides of radial bending line along tangent line to surface of blank until occurrence of gap between blank and master pattern. Then blank is drawn until close contact of its surface to master pattern. EFFECT: enhanced accuracy of selecting thickness and material of blank. 1 dwg