The design principle of a press is to convert rotary motion into linear motion. The main motor provides power to drive the flywheel, which drives the gears, crankshaft (or eccentric gear), connecting rod, and other components through the clutch, thereby achieving the linear motion of the slide. The motion from the main motor to the connecting rod is rotary motion. A transition point between rotary motion and linear motion is required between the connecting rod and the slide. There are generally two types of mechanisms in its design: ball type and pin type (cylindrical type). This mechanism converts rotary motion into the linear motion of the slide.

A press applies pressure to the material, causing plastic deformation to obtain the required shape and precision. Therefore, a set of dies (upper die and lower die) must be used, with the material placed between them and pressure applied by the machine to deform it. The reaction force generated by the force applied to the material during processing is absorbed by the press mechanical body.