① the hydraulic rubber forming: installed in the capacity box, rubber tires filled with high pressure liquid and causes them to expand, so as to promote wool according to the bobbin shape parts. Formed parts with high accuracy, no indentation on the surface. Rubber tires are a common flexible die, so the bench can be placed several different shapes of bobbin. Hydraulic press can die out multiple components in a single cycle, high efficiency, and low cost. This method is mainly used for forming ribs, bulkhead light bending parts, equipment for the rubber band used by hydraulic machines.
② stretch bending: wool stretch along the length of first profile to limit and keep pulling and wool according to the type of bending die of bending. Prior stretching can effectively change the bending stress distribution in a wool, so as to improve the accuracy of parts. Equipment used for arm-bending machine and Rotary stretch-bending. Bending machine for forming a one-way rotating-arm bent, such as bending angle is greater than 180 ° of the bulkhead, the Purlin and so on. Rotary stretch-bending can be unidirectional bending, biaxial bending and forming and bending angle is 360 ° ring box.
③ PEEN forming: use compressed air (or high speed impeller) many of the steel shot diameters 0.3~2.5 mm from the nozzle. EHL combat wool on one side of the surface at high speed, so that the surface layer of metal size increases because of the crowd, resulting in stress, bending the wool to the side that is not hit by the projectiles, shape of the surface. PEEN forming is a large integral Panel of main forming methods. This approach improves the fatigue strength of parts, equipment and process equipment used is relatively simple.
Black stretch-forming: before forming longitudinal end clamp clamp made of wool (cross) or horizontal head (vertical), and forming die for lifting, stretching with the coordinated movements of clamping, make the wool to produce curved and non-uniform stretching and progressive forming die for the fitting. This method is mainly used to produce the aircraft fuselage and wing skin, rocket Panel, welding of the tank bottom and other large size parts.