CNC Tube Bending

CNC tube bending forms tubing to programmed angles and radii with high repeatability, supporting multi-bend geometries and controlled orientation for production runs.

Overview

CNC tube bending uses a programmable bender to form straight tube into precise angles and compound shapes with controlled bend sequence, rotation, and feed. It’s commonly paired with rotary-draw tooling and can run multiple bends in one cycle, keeping geometry consistent across parts.

Choose it for repeatable multi-bend tubes where bend locations, angles, and clocking matter—frames, handles, brackets, fluid lines, and structural tube assemblies. It fits prototyping through production when you want fast changeovers via stored programs and reduced operator variability.

Tradeoffs: tight centerline radii and thin walls increase risk of ovality, wrinkling, or wall thinning; complex parts may require dedicated tooling and careful bend sequencing to avoid collisions. Dimensional variation often comes from springback and tube lot-to-lot changes, so expect setup/first-article tuning and plan inspection around critical bend angles, tangent lengths, and end-to-end features.

Common Materials

  • 304 Stainless Steel
  • 316 Stainless Steel
  • Aluminum 6061
  • A513 Steel Tube
  • Copper C110
  • Titanium Grade 2

Tolerances

±0.5° bend angle; ±0.020 in bend location (typical, varies with tube size/radius)

Applications

  • Hydraulic hard lines
  • Automotive exhaust sections
  • Handrails and grab bars
  • Bike and motorcycle frames
  • Medical equipment frames
  • HVAC/refrigeration tubing assemblies

When to Choose CNC Tube Bending

Pick CNC tube bending when the part has multiple bends with critical bend angle, rotation (clocking), and tangent lengths that must repeat across builds. It’s a strong fit for small-to-high volumes where a stable program reduces operator dependence and supports consistent inspection. It also works well when you need quick iteration on bend geometry without re-training the process each run.

vs Mandrel Bending

Choose CNC tube bending when the primary need is repeatable multi-bend geometry, accurate rotation between bends, and fast program-driven changeovers. Mandrels are a tooling option for controlling ovality/wrinkling on tight radii; CNC bending can be run with or without a mandrel depending on wall thickness and CLR.

vs Rotary Draw Bending

Choose CNC tube bending when you need automated control of feed, rotation, and bend sequencing for parts with several bends and tight clocking requirements. Rotary draw describes the bending method; CNC adds programmability, repeatability, and faster setup for production and revision control.

vs Compression Bending

Choose CNC tube bending when you need better control of bend location, rotation, and overall repeatability for assemblies and multi-bend parts. Compression bending is typically simpler and lower-cost for large radii and less cosmetic/precision-critical work, but it’s more sensitive to distortion and variation on tighter bends.

vs Roll Bending

Choose CNC tube bending when the part needs discrete bend angles, short tangent lengths, and accurate end-to-end geometry. Roll bending is better suited to long, gradual radii and arcs, but it’s not efficient for tight, indexed multi-bend shapes.

vs Stretch Forming

Choose CNC tube bending when you need compact bends with defined tangent points and multiple orientation changes along the tube. Stretch forming excels at large-radius, smooth curves with low wrinkling risk, but it’s less suited to tight radii and short, segmented geometry.

Design Considerations

  • Specify tube OD, wall thickness, material/temper, and required centerline radius (CLR) for each bend to avoid quote assumptions
  • Call out critical-to-function dimensions (bend angles, tangent lengths, end-to-end, and clocking) and allow noncritical features to float
  • Avoid extremely tight CLR-to-OD ratios on thin wall tubing unless you plan for mandrel/wiper tooling and accept ovality limits
  • Leave sufficient straight length at tube ends for clamping and post-ops (cutting, notching, flaring, beading)
  • Model and dimension rotation between bends (clocking) using a consistent datum and view to reduce interpretation errors
  • Plan piercings/slots and welded tabs after bending when possible to prevent distortion and tool interference