Straightening machine is a straightening equipment for metal profiles, bars, pipes, wires, etc. The straightener changes the straightness by extruding the bar with straightening roller. Generally, there are two rows of straightening rolls with different quantities. There are also two roll straighteners, which straighten materials with different diameters depending on the angle change of two rolls (concave in the middle, hyperbolic roll). The main types are pressure straightener, balance roll straightener, shoe roll straightener, rotary reverse bending straightener and so on.