METHOD FOR BACKWARD EXTRUSION OF CYLINDRICAL AND PRISMATIC ARTICLES AND APPARATUS FOR PERFORMING THE SAME Russian patent published in 2001 - IPC

FIELD: plastic metal working, namely backward extrusion at making cylindrical and prismatic articles. SUBSTANCE: method comprises steps of making blank with hole for extrusion, filling hole of blank with elastic medium block, forming on end surface of blank annular groove and filling it with lubricant. At working effort for extrusion of blank is accompanied by counterpressure along outer edge of extruded article. In description of invention formulae are given for calculating blank thickness and opening diameter in dependence upon outer and inner diameters of article and its thickness in bottom portion. Apparatus for performing the method has die with beaded inner cavity. Working surface of bead is flush relative to bottom portion of punch. Working surface of die has more intensive roughness than working surfaces of punch and bottom rod. EFFECT: reduced value of extrusion effort, lowered power consumption, enlarged manufacturing possibilities. 2 cl, 6 dwg