Four column hydraulic machine is a utilizes the oil pump conveying hydraulic oil of the static pressure to the processing of metal, plastic, rubber, wood powder and other products, machinery and equipment. It is used in pressing process and press forming process, such as forging, stamping, cold extrusion, straightening, bending, flanging, sheet metal deep drawing, powder metallurgy, pressure equipment and so on. The principle of it is to use Pascal's law to make use of liquid pressure transmission machinery, a lot of types. Of course, use is also based on the need to be a variety of. Such as the pressure of the liquid to the type of liquid to be divided, there are two types of oil press and hydraulic press.