Pipe bending, is a process in which the pipes having a certain shape and design are reshaped. This process is applicable to metals, alloys, aluminum, titanium and steel. Various pipe bending methods are used depending on the relevant material and the desired accuracy level. Most popular methods are rotary draw bending, 3-roll bending, compression bending and ram bending (press bending).
When rotary draw bending is applied, the tube is fastened between the bend die and the clamp die. The rotation of both tools around the bending axis bends the tube to the radius of the bend die. The pressure die (slide piece) serves the purpose of receiving the radial stress, which is generated during the forming process, and supports the straight tube end from outside. If a mandrel and wiper die are additionally applied (mandrel bending), a high quality work piece can be achieved even with thin-walled pipes and tight bending radius.
Compression bending is similar to rotary draw bending. This bending method is carried out with a sliding carriage and a stationary bend die, between which the tube is clamped. The sliding carriage, which rotates around the radius block, bends the tube to the radius of the bend die.
When ram bending is applied, bending tool is pressed against two counter-rollers, either manually or by means of hydraulics. This motion forces the tube inserted between the radius block and the counter-rollers to bend around the radius. The tube cannot be supported from within; therefore this method is suitable for thick-walled tubes and large bending radius only.
3-roll bending is also used for producing work pieces with large bending radii. The method is similar to the ram bending method, but the working cylinder and the two stationary counter-rollers rotate, thus forming the bend
In our company, compression bending procedures are in the use.