Controlled material flow hydroforming

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. A basic die is mountable to the press and specific tooling is replaceably mountable to the basic die. The basic die includes a riser, a manifold and hydraulic cylinder assemblies. A sheet metal blank is positioned on the lower die and is 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. The cylinder assemblies cause hydraulic fluid to be forced into a region between the clamped blank and the lower die and form the blank in the part print cavity. 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 double action presses.