APPARATUS FOR EXPANDING TUBULAR BLANKS Russian patent published in 1997 - IPC

FIELD: plastic metal working, namely forming of tubular blanks of different sheet materials. SUBSTANCE: apparatus includes base whose upper portion is made of highly electrically conductive material and lower portion of electrically insulation material. Electric current conduit is secured to said base and connectable die in metallic holder is mounted onto it. Punch with electric current conduit is mounted on upper cross bar through electrically insulation sleeve. Tubular blank filled by loose material is arranged inside inner cavity of die. At operation punch compresses container with loose material and blank is deformed by said container at multiple passing electric current pulses through it. EFFECT: enhanced quality of tube, increased operating efficiency. 1 dwg