Problems in implementation of cold extrusion of steel deep bushings with bottom on universal presses and their solution by creating of specialized presses

The design of a die that ensures the coaxiality of the punch and die during extrusion of parts with deep cavities and also withstands large axial force acting in the center of its support plate is considered. The use of cold die forging by extrusion is limited by large stresses in the punches. Extrusion with actively directed stresses of contact friction along the lateral surface of the extruded workpieces allows unloading the punch. To perform such forging, the die is moved along the lateral surface of the extruded workpiece in the direction of metal flow. Since the bottom of the extruded workpiece cannot have support in the movable die and rests directly on the lower plate of the die, a large concentrated force acts in the center of this plate. The universal presses are not designed for the action of such a force in the center of their tables. A calculation of the die elements that ensure compensation for the force acting in the center of its lower plate is presented. It is shown that when using the specialized presses the described problem is absent.