The ABCs of Multi-Radius Tube Bending

Many bends in one cycle

Multi-radius bending is commonly used for complex parts when one continuous pipe or tube requires two or more center line radii. It is a good fit for parts with a large centerline radius, where hard tooling may not be an option or for complex parts that need to be formed in one complete cycle.

Changeovers between left-hand and right-hand bending heads can be repeated as many times as needed, allowing complex shapes to be fabricated completely, without removing the tube or involving any other machines.

Although this method is commonly requested for parts made of steel or stainless steel, most industrial metals, wall thicknesses and lengths can be accommodated.

Getting Started

To create a multi-radius bend, the machine is set according to the tube geometry listed in the bend data sheet or production print. These coordinates and LRA data (length, rotation and angle) are either entered to the machine manually or uploaded from the customer record for each particular part.

Next, a simulation is done on the part to ensure that the tube will successfully clear the machine and tooling as it is bent, looking for any collision or interference. If needed, adjustments are made to the software, clamps, head or other parts on the bending machine before the start of the process.

Mandrels, or inserts for the tube or pipe, are sometimes incorporated to ensure that the tube maintains its shape and integrity during the bending process.

Once the machine is set, the tube or pipe is inserted into the collet of the machine, which clamps onto the part to guide its movement. The machine then runs through the program, making the entire part in one cycle. 

Applications

Multi-radius bending is ideal for exhaust and emissions control, oil and gas and other process applications where interior surfaces must be consistent in order to withstand pressure, flow rate and volume of the material going through the tube or pipe. This type of bending is also used to create components for heavy equipment and a variety of structural frames.  

With dual head machine technology, bending and setup is customized to successfully deliver both small and large radii on the same part. This ability to do multiple bends on one part in one cycle is what makes multi-radius bending ideal for both high-volume orders as well as complex, highly engineered parts.

This blog was co-authored by Marshall Arndt, Manufacturing Engineer, and Daniel De La Santos, Head Bender, Sharpe Products.