The variable displacement piston pump in a hydraulic press regulates the amount of hydraulic oil sent to the master cylinder. This precise flow control affects the speed and compression force of the press.

As the pressure increases, the speed decreases proportionally and this offers flexible adjustment of the machine and allows better use of the pressure of the hydraulic press in certain types of processing. This does not happen, however, in the standard versions without variable displacement piston pump, where the transition between the approach speed and the working speed is immediate.