The bend is one of the most important parts in manufacturing. Too many products are manufactured using pipes, and the precision molding of tubes is a key part of manufacturing today.Do you know the different types of tube bending?

Press Bending

Press Bending is a simple form of tube bending. Using a Pipe pressing machine, a simple “bend mold” is pressed against the tube or pipe which is straddled across two fixed supports forcing it to conform to the shape.

Figure 1   BLMA Pipe pressing machine

Roll Bending

Roll bending is another method of pipe bending, which uses 3 or 4 or 7 roller machines called Angle rollers or cross section rollers to pull pipe or tubing over rollers while pressing the tubing into larger and larger bends. This method, much like press bending, uses a support roll and a press roll, and this method can be bent at various angles using the same type of roll. Is a simple and accurate method of bending a variety of radius, and does not require the use of a specific tool for the desired bending radius.

Figure 2   BLMA Pipe rolling bending machine

Rotary Draw Bending

Rotary Draw Bending is by far the most popular form of tube bending as it is easiest to control, more precise,repeatable and a relatively affordable tube bending system. A Rotary Draw Bending system is made up of  three different tools, the Clamping Die, the Pressure Die and the Radius Die that hold and form the tube throughout the bending process. The tube is clamped to the bend die and is ‘drawn’ around the die by the machine by either hydraulic or electric methods. As the bending die rotates the tubing is held in place firmly against the rotating bend die by the pressure die. 

Mandrel Tube Bending

Mandrel bending are actually made by adding internal supports or mandrels so that the walls remain firmly in place during the molding process. A mandrel is added, inserted into the tube and controlled by the machine during bending so that the tube does not collapse on its own as it is stretched and formed around the bending mould. The mandrel is only slightly smaller than the inner diameter the pipe is bent and fixed with several flexible supports on the flexible ball mandrel at its end. These spherical mandrels bend with and allow the tube to bend while supporting the entire diameter of the tube while the tube wipes the mandrel throughout the bending process.

Figure 3   BLMA mandrel Pipe bending machine