Tube Bending

Tube bending forms straight tubing into controlled curves using dies or rollers, maintaining roundness and repeatability for routed fluid, structural, and frame parts.

Overview

Tube bending forms metal tubing into arcs and multi-plane shapes using processes like rotary draw, mandrel, compression, and roll bending. Shops bend to a specified centerline radius (CLR), angle, and orientation, often with CNC benders to hold bend sequence and rotation between bends.

Choose tube bending when your part is primarily a routed path—fluid or gas lines, handrails, frames, or welded assemblies—and you want fewer welds, better flow, and consistent geometry across production. It’s well suited to low-to-medium volumes with repeat bends, and it scales efficiently once tooling and programs are proven.

Tradeoffs: tighter radii and thin walls increase risk of ovality, wrinkling, and wall thinning; mandrels and wipers add cost but improve quality. Multi-bend parts can stack up length and angle errors, so clear datums and inspection points matter. Tooling lead time and minimum straight lengths at tube ends often drive design changes.

Common Materials

  • Stainless Steel 304
  • Stainless Steel 316
  • Aluminum 6061
  • Carbon Steel 1020
  • Copper C122
  • Titanium Grade 2

Tolerances

±0.030 in (bend angle ±0.5° typical)

Applications

  • Hydraulic hard lines
  • Exhaust and intake tubing
  • Roll cage and tubular frames
  • Handrails and guardrails
  • Heat exchanger and condenser coils
  • Furniture and fitness equipment frames

When to Choose Tube Bending

Tube bending fits parts defined by a bend path where maintaining tube continuity matters for flow, strength, or appearance. It works best when you can specify a reasonable bend radius and allow standard straight lengths at the ends and between bends. Repeat production benefits most because setups and bend programs are reusable.

vs Tube Cutting

Choose tube bending when the functional geometry comes from curves rather than straight segments. Bending reduces the number of cut pieces and welded joints, improving leak integrity and appearance while shortening assembly time.

vs Tube Forming

Choose tube bending when you need controlled radii, angles, and multi-bend orientation along the tube centerline. Forming operations are better for changing the tube’s cross-section; bending is better for routing without intentionally reshaping the profile.

vs Welding/Fabrication (mitered elbows)

Choose tube bending when you want smooth flow, fewer welds, and cleaner cosmetics than segmented elbows. Bending also improves repeatability for production runs by eliminating fit-up variation at multiple weld joints.

vs Extrusion + Secondary Ops

Choose tube bending when you need seamless or welded tube in standard sizes routed into 2D/3D shapes. Extrusion makes constant cross-sections but won’t create the bend geometry without a bending step anyway.

Design Considerations

  • Specify tube OD, wall thickness, material/temper, and required bend method (mandrel/non-mandrel) if ovality or wrinkling limits are tight
  • Call out bend radius as centerline radius (CLR) and include bend direction/rotation for multi-plane parts
  • Allow minimum straight lengths at tube ends and between bends based on tooling; short tangents drive custom tools and cost
  • Avoid bend radii that are too tight for the wall thickness; tighter CLR increases thinning, ovality, and risk of wrinkling
  • Define inspection datums and critical-to-function dimensions (overall length, end-to-end, clocking) to control stack-up across multiple bends
  • If ends get flared, beaded, threaded, or notched, indicate whether bending happens before or after those features to prevent rework and distortion