METHOD FOR FORMING AND DRAWING ENVELOPE PARTS WITHOUT WALL THINNING Russian patent published in 1998 - IPC

FIELD: plastic metal working, namely shaping spheric, cone and other shaped sheet parts by elastic medium with use of rigid die without thinning walls of parts at plastic working. SUBSTANCE: method comprises combination of reversing and friction drawing processes. At shaping process central zone of blank is locked by supporting insert arranged in center of die for accurately centering blank relative to said die. Ring-like punch frictionally acts upon flange of blank for intensively pushing it into die cavity in order to create compression stresses in central zone of blank instead of tension meridional stresses. EFFECT: enhanced efficiency. 2 dwg