Click to ExpandUnderstanding Tube Bending Fundamentals

Tube bending is the process of bending a tube or a pipe to create the curves and shapes required for a particular application. For many projects, bent tubes are more useful than straight ones: handles and railings, trombones, HVAC equipment, automotive parts, furniture frames, and more. Tube bending can be a cold form or hot form process, depending upon the needs of the application.

Cold Form Tube Bending
Cold form tube bending is a quick process that doesn’t require any additional heat and instead relies on physical force to create the curve. While cold bending may have its limitations, it’s an affordable choice that’s used in the construction, shipbuilding, bridge building, automotive, food processing, and petrochemical industries, among others.

With cold form tube bending, you can create components with large radii and multiple angles. There is no risk of thermal deformation and the original metal properties remain intact.

There are five commonly used cold bending processes:

  • Press Bending. In press bending, the tube is fixed in place and the bend die is pressed against the tube to create the curve. This long-used technique is quick and reliable for symmetrical parts that don’t require a consistent cross-section.
  • Rotary Draw Bending. Commonly used for pipe fittings, handrails, instrument tubing, and components for automotive and aerospace applications, rotary draw bending is used for precise bends with a constant diameter.
  • Compression Bending. Because the setup is simpler, compression bending is more economical than rotary draw bending. However, it can’t be used for small center-line radii due to the lack of support for the inner diameter of the tube during the bending process.
  • Roll Bending. The tube is worked back and forth on a set of rotating rollers, which gradually create the bend radius. Roll bending is used to make spiral tubes and bends in large tubes.
  • Bending Springs. Used for PVC and soft copper pipes, bending springs are placed into the tube and gently pulled from each side to create the bend. It’s not especially accurate or repeatable, but it’s simple, fast, and useful for household tube bending projects when consistency isn’t required.

Hot Form Tube Bending

Though more complex and expensive than cold forming, hot form tube bending processes, including heat induction bending and sand packing hot-slab bending, allow for high-accuracy forming to meet your exact specifications. The resulting component offers excellent strength, and the material retains its thickness. For complex projects with tight tolerances that require exceptional accuracy and repeatability, hot form bending is a popular choice. It’s used for components in the agricultural, mining, automotive, plumbing, and construction industries, among others.

Freeform Tube Bending

Freeform bending is an innovative tube bending method that uses a movable die capable of bending complex parts without needing to change the bending tool. The technique is ideal for multi-radius bends with very little distance in between and angles of more than 180 degrees. It’s easy to make modifications to the project as you work, which makes it an excellent method for prototyping. Roll bending is a type of freeform bending.

Form Bound Tube Bending

Form bound tube bending is a technique that bends or forms the tubing based on the geometry of the die. It can be manual or performed with machines and includes techniques like rotary draw bending, compression bending, and mandrel bending.

Tube Bending from TBSI

At TBSI, we leverage years of experience in tube bending to meet the needs of a variety of applications. With competitive pricing, quick lead times, and personalized service, we’re committed to helping you solve project challenges and deliver effective solutions. Contact us to learn more about tube bending, CNC forming, wire forming, and other forming solutions, or request a quote for your project today.

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