TW234095B - Controlled material flow hydroforming - Google Patents

Abstract

A self-contained apparatus for forming metal sheet is adapted for operation within a standard double action press having a base and outer and inner vertically reciprocating slides and includes a basic die mountable to the press and specific tooling replaceably mountable to the basic die. The basic die includes a riser mountable to the outer slide, a manifold mounted atop the base of a tub, and hydraulic cylinder assemblies mounted atop the base and in connection with the manifold and mechanically actuatable by the inner slide for providing pressurized fluid to the specific tooling. The specific tooling includes mating upper and lower dies connected to the riser and manifold, respectively, and movable between open and closed positions. A sheet metal blank positioned upon the lower die is wrapped around the upper die as the upper die is moved down to a closed position by the outer slide, the blank being clamped between the upper and lower dies whereby the periphery of the blank is gripped between a male and female bead mounted all around a part print cavity in the upper and lower dies, respectively. The outer slide then dwells while the inner slide moves down, engaging and actuating the cylinder assemblies, causing hydraulic fluid to be forced into a region between the clamped blank and the lower die, the blank being formed into the part print cavity defined in the upper die. The male bead exerts varying control on the sheet to allow it to stretch across portions of the cavity while flowing into other portions of the cavity. A locking mechanism prevents the bending of the dies and holds the dies in a closed position thereby assisting the engagement of the male bead with the female bead. As a safety feature, the mechanism is configured to automatically open when the die cavity is moved up. The locking mechanism allows the use of high pressures to make large parts, such as car hoods, doors, deck lids, and quarter panels in conventional currentlyavailable double action presses.