On this machine, the bent tube is impacted by a hydraulic cylinder and propelled at a certain distance by a feeding hydraulic cylinder, after which another hydraulic cylinder will drive the rack-and-pinion mechanism to rotate the mandrel and make the tube 90°or 180°bending. This machine is used for heating components of U type. In addition, it is controlled by PLC and the propelled length is controlled by the signals that the photoelectric switch sends out. What's more, the bending angle can be realized by controlling the process of the oil cylinder. The disadvantage is that the switch should be modulated accurately when you change another component.