The hydraulic press is based on the Pascal principle: the pressure of the closed system is a fixed value. A part of the hydraulic press is a piston, which acts like a pump. Its cross-sectional area is small and produces a small force. The other part is a piston with a larger area. The pressure of the two is the same, and the piston with a larger area exerts a larger force. If the pump and the press hydraulic cylinder are separated, only a small diameter pipe is needed to connect the pump and the hydraulic cylinder, which is easier to resist the liquid pressure.
When the piston moves, the liquid (such as hydraulic fluid) in the hydraulic cylinder will also move with it. Assume that the liquid is not compressible. The oil volume affected by the small piston displacement is equal to the oil volume affected by the large piston displacement. Therefore, the displacement distance of the two will be different, which is inversely proportional to the piston area. Therefore, in order for the large piston to move, the small piston needs to travel a long distance. The large piston has a larger output, but has a shorter displacement, and a smaller piston receives a smaller force but has a longer displacement, so it conforms to the law of conservation of energy. If the area of the large piston increases, its moving distance will be shorter.
The concept of hydraulic presses can also be used in the hydroforming process.
