The working principle of the friction screw press is to use the contact transmission of the flywheel and the friction disk, and to work by the principle of relative movement of the screw and the nut. The press is usually driven by the motor through the friction disk to drive the flywheel rim to rotate the flywheel, so this type of press is also called a friction press. The largest friction press in China is 25 trillion Newton. Larger presses use a hydraulic system to drive the flywheel , Known as hydraulic screw press, the largest specification is 125 trillion N. Later, there was an electric press that directly drives the flywheel with a motor. It has a compact structure and fewer transmission links. Due to frequent commutation, it requires higher control electrical appliances, and requires a special motor.
There is no fixed bottom dead center of the rotary press, and the larger die forgings can be shaped multiple times, and can be singles, continuous and inching. The striking force is related to the amount of deformation of the workpiece. When the deformation is large, the striking force is small, and when the deformation is small (such as cold strike), the striking force is large. In these respects, it is similar to the forging hammer. However, its slider speed is low (about 0.5 meters/ Seconds, only 1/10 of the forging hammer), the impact force is closed by the frame, so the work is stable, the vibration is much smaller than the forging hammer, and no large foundation is required. The automatic heat press is equipped with a slip insurance mechanism to maximize the impact force Limit to less than twice the nominal pressure to protect the safety of the equipment.
The lower part of the press is equipped with a forging ejection device. The screw press has the function of various screw press forging machines such as die forging hammer and mechanical press. It has strong versatility and can be used for die forging, punching, drawing and other processes. In addition , Screw presses, especially friction presses are simple in structure and easy to manufacture, so they are widely used. The disadvantage of screw presses is lower productivity and mechanical efficiency.