METHOD FOR WORKING OPENINGS AT USING FLUID PRESSURE AND APPARATUS FOR PERFORMING THE SAME Russian patent published in 2004 - IPC

FIELD: metallurgy, namely processes of cold plastic working of openings by piercing mandrel with use of viscous lubricant placed between deforming tool-mandrel and opening of blank. SUBSTANCE: method comprises steps of filling opening with lubricant; placing blank in die mounted in apparatus placed on table of hydraulic press; pushing mandrel through opening by means of plate of hydraulic press; controlling pressure of lubricant which influences upon quality of piercing by means of throttle connected with cavity of die. Apparatus includes punch for mounting mandrel; die for placing blank; spring-loaded stop; throttle and knocking out member. At reverse stroke of mandrel stop holds article in die. When mandrel is out of opening, knocking out member automatically knocks article out of die. EFFECT: simplified design, enlarged manufacturing possibilities. 4 cl, 2 dwg