Tube Rolling Processes Explained: A Comparison of Tube Bending Types
There are numerous different types of tube bending processes that are commonly used in the fabrication of tubular industrial components. Likewise, today’s commercial fabrication shops utilize a wide range of different tube rolling machines which are optimized for specific bending processes or unique product configurations.
The Different Types of Industrial Tube Bending Services Explained
As the name suggests, tubular roller bending machines utilize a series of drum rollers which precisely push the tube stock through a coil which is positioned at an exact bend angle. Most roll forming machines use a 3-roller or 4-roller configuration to accurately control the bending of the tube. Roll bending machines are also commonly used to process flat sheets for sheet metal fabrication projects.
Advantages of Roll Bending
- Can accommodate multiple tubing diameters with the same tooling.
- Capable of bending in multiple planes for more complex geometries.
Disadvantages of Roll Bending
- Roll bending is a relatively slow process compared to many other tube bending services.
- Not optimized for thin tubing or small-radius bends.
- A more complicated setup process through trial and error is often needed before the desired accuracy is reached.
Rotary draw bending services are capable of producing extremely accurate bends for complex tubular components. The rotary draw process consists of clamping the tube stock around its diameter and carefully bending the tube around a die tool. The bending die tool therefore must be precision machined and formed to the exact required dimensions of the tubes’ bend radii.
Advantages of Rotary Draw Bending
- Extremely accurate bends with high precision and repeatability.
- Higher speed and a more streamlined process compared to roll bending.
Disadvantages of Rotary Draw Bending
- Setup cost can be relatively expensive if custom bending dies are required.
- Tooling must be switched out and set up for different bend radii and tube shapes/diameters.
Mandrel Die Bending
Mandrel bending is a specialized rotary draw bending process that is even more reliable and repeatable. An internal mandrel assembly is inserted into the tubing prior to bending. The mandrel generally consists of a rod that is fitted with multiple toroidal-shaped guides which support the internal structure of the tube as it is being bent. This allows for the manufacturing of more complex tubular components with tight-radius bends while reducing the risk of crushing/splitting the tube stock.
Advantages of Press Bending
- A relatively economical and high-speed tube bending process.
Disadvantages of Press Bending
- Lack of flexibility, with each unique tube shape and size requiring a custom die tool.
- Relatively low accuracy and precision compared to other tube bending processes.
- Not optimized for thin tubing or brittle materials.
Tubular ram bending is similar to press bending in that multiple precision-formed dies are used. In the ram bending process two of the dies are stationary, while a third pressure die applies force to produce a triangularly bent geometry. Like pressure bending, ram bending is not the most precise or reliable tube bending service; however, it is a relatively fast and easy fabrication method for simpler components.
Advantages of Ram Bending
- A relatively simple and low-cost tube bending service.
- High-speed bending processes.
Disadvantages of Ram Bending
- Not as precise as more advanced tube bending services.
- Is more likely to damage tube stock due to compression.
Reading, PA’s Leading Contract Manufacturer for Tubular Industrial Fabrications
Alloy Fabrication is proud to be Reading, Pennsylvania’s leading manufacturer of quality industrial tube bending services. We have provided a diverse range of commercial fabrication projects with their critical tubular components and custom tube-bent assemblies. Since 1987, our company has remained dedicated to delivering superior American metal forming solutions and precision fabrication services.