Process and apparatus for achieving narrow workpiece tolerances in drop-forging, especially in isothermal forging

A process for achieving narrow workpiece tolerances in drop-forging, especially in the isothermal forging of heat-resistant materials, where the two die halves (1, 2) representing the die, which are at the workpiece temperature or virtually at the workpiece temperature, experience a movement relative to one another under the influence of the press forces, in such a way that their position relative to one another diverges from the geometrical nominal value in the course of the pressing operation, wherein a first workpiece is introduced into a forging press between the die halves, wherein, according to a first step of the pressing operation, the position of the die halves (1, 2) relative to one another is measured by mechanical means (14, 15, 16) or physical means (10, 11, 12, 14), with the die halves (1, 2) closed, in an xy plane perpendicular to the direction z of the press force exerted and is evaluated via a computer and control unit (27, 28, 29, 30) located outside the forging press, wherein, in a second step, the forging press is temporarily relieved of pressure, the two die halves (1, 2) are separated from one another and the first workpiece is removed from the forging press, and wherein the position of the two die halves (1, 2) relative to one another is positively corrected by mechanical means (6, 17, 19, 20, 21;

• 6, 17, 21, 23, 24, 25, 26) according to the measurement result, a second workpiece is introduced into the forging press, and in a third process step the pressing operation is completed at one stroke, with the die halves (1, 2) in their corrected position, any cooling of the workpiece and die being avoided at the same time.