The working principle is that the active shaft and the passive shaft ensure synchronous operation through the open gear. The passive bearing housing is equipped with hydraulics at the rear. The screw feeding device of the dry powder ball press is driven by the electromagnetic speed regulating motor, and is rotated by the pulley and the worm reducer to force the pressed material into the main feed port. Due to the constant moment characteristic of the electromagnetic speed regulating motor, when the amount of material of the screw feeder is equal to the amount of material required by the main machine, a constant supply pressure can be maintained to stabilize the pellet mass. If the feeding amount is too large, the feeding device is overloaded; if the feeding amount is too small, the ball is not formed. Therefore, the skilled operation technique is an important condition for ensuring the normal operation of the ball. The dry powder ball press is mainly driven by a hydraulic pump to drive high pressure oil into the hydraulic cylinder to cause axial displacement of the piston. The front joint of the piston rod is placed on the bearing housing to meet production pressure requirements. When the feed between the two pressure rollers is too much or enters the metal block, the hydraulic cylinder piston rod is under pressure overload, the hydraulic pump will stop, the accumulator will buffer the pressure change, the relief valve will open the oil return, and the piston rod will be displaced. The gap between the pressure rollers is increased to allow the hard objects to pass through the pressure roller, and the system pressure returns to normal, so that the pressure roller can be protected from damage. The machine can adjust the pressure according to the requirements of the pressure ball density, and the production is flexible.