Straightening machine is a device for straightening metal profiles, bars, pipes, wires, etc. The straightening machine squeezes the bar and the like through the straightening roller to change the straightness. There are generally two rows of straightening rollers, varying in number. There are also two-roller straighteners, which rely on the angle change of the two rollers (inner concave, hyperbolic roller) to straighten materials of different diameters. The main types are pressure straighteners, balanced roll straighteners, shoe roll straighteners, rotary reverse bend straighteners, etc.