Tube Forming

Tube forming reshapes tube ends or entire sections—expanding, reducing, flaring, beading, or hydroforming—to create functional joints and complex hollow geometries.

Overview

Tube forming reshapes hollow stock by expanding, reducing, flaring, swaging, beading, or hydroforming the tube rather than cutting away material. It creates functional end-forms, seal surfaces, and cross-section changes that enable leak-tight joints, attachment features, and complex load-bearing structures.

Use tube forming when you need shaped tube ends, localized diameter changes, or non-round sections without adding fittings or welds. It is well-suited for medium to high volumes where dedicated tooling spreads out the cost and where consistent geometry and wall thickness are critical, such as fluid lines, frames, and manifolds. Tradeoffs include tooling cost, forming limits driven by wall thinning and wrinkling, and tighter requirements on material quality and lubricants. Hydroforming within this category can combine multiple parts into a single, complex tube, but needs higher tonnage presses and more engineering upfront. Designing for manufacturable expansions, reductions, and radii keeps costs under control and improves yield.

Common Materials

  • Mild steel
  • Stainless steel 304
  • Aluminum 6061
  • Copper
  • Titanium Grade 2

Tolerances

±0.010"

Applications

  • Automotive exhaust and intake manifolds
  • HVAC and refrigeration tubing assemblies
  • Hydraulic and brake lines with formed ends
  • Bicycle and motorcycle frame members
  • Medical instrument and catheter tubes
  • Furniture and fitness equipment tubular frames

When to Choose Tube Forming

Choose tube forming when you need functional end-forms, cross-section changes, or integrated features in hollow parts without adding fittings or welds. It fits best for repeat production where tooling cost is justified and where consistent wall thickness and seal surfaces matter. Hydroforming within tube forming is ideal when you want to consolidate multiple welded pieces into a single, complex hollow component.

vs Tube Cutting

Choose tube forming when you need shaped ends, expansions, reductions, or beads that create sealing, assembly, or structural features, not just length control. Cutting only establishes tube length and basic edge condition; forming converts that simple tube into a functional connection or structural node, often eliminating separate fittings.

vs Tube Bending

Choose tube forming when the primary requirement is end geometry, localized diameter change, or special profiles, rather than overall tube routing. Bending controls the tube path in space; forming adds the end-forms and features that actually mate, seal, or locate in the assembly, so many parts require bending followed by forming.

vs CNC machining

Choose tube forming when you need to preserve a continuous bore and thin wall, and material removal would be slow or weaken the tube. Forming reshapes the tube wall efficiently with minimal scrap, while machining thin-walled tubing risks chatter, distortion, and higher cycle times for comparable features.

vs Metal Stamping

Choose tube forming when the part must remain hollow with a continuous internal passage, such as fluid or gas lines. Stamping is better for flat or shallow drawn profiles, but forming and hydroforming can deliver closed-section strength and complex 3D shapes with lower mass and integrated connection points.

vs Welding and fabricating from fittings

Choose tube forming when you can replace multiple fittings and welds with a single formed feature, improving flow and reducing leak paths. Forming can lower assembly time, simplify logistics, and improve fatigue life by eliminating weld toes and alignment variability, at the cost of upfront tooling engineering.

Design Considerations

  • Limit expansions and reductions to realistic percentages of original diameter to avoid excessive wall thinning or wrinkling; consult your supplier’s forming limits early
  • Provide adequate straight length from tube end for clamping and tooling engagement before the first bend or form
  • Use generous internal and external radii on transitions to reduce splitting risk and tool wear, especially on high-strength or thin-wall materials
  • Specify tighter tolerances only on truly functional features such as seal diameters, bead locations, and critical lengths; leave everything else as reference
  • Call out material grade, wall thickness, and condition (annealed, as-drawn, etc.) clearly, as formability depends heavily on these details
  • Include sections and detailed views of formed areas in drawings or models so shops can design appropriate tooling and accurately estimate feasibility and cost