A high-pressure system for hydroshaping a hollow workpiece has a lower die
and an upper die vertically shiftable above the lower die and forming
therewith a cavity shaped to hold the workpiece. An upper actuating
element bears downward via a vertically compressible hydraulic operating
cylinder on the upper die. A spring-loaded pressure-storing cylinder is
connected by a hydraulic line to the operating cylinder and to the
workpiece. Downward shifting of the actuating element first closes the
dies together, then internally pressurizes the workpiece via the line
from the operating cylinder such that the workpiece deforms and shapes
itself to the cavity, and then fills the spring-loaded pressure-storing
cylinder. Subsequent upward shifting of the actuating element at first
allows the pressure-storing cylinder to empty, and then entrains the
upper die upward off the workpiece by the actuating element.