Extrusion

Extrusion forms continuous, constant-cross-section profiles by forcing metal through a die, delivering high material utilization and consistent geometry at production volumes.

Overview

Extrusion pushes metal through a shaped die to create long parts with a constant cross-section. Hot metal extrusion improves formability and enables larger reductions; cold metal extrusion improves surface finish, strength, and dimensional control. The process is typically followed by cutting to length, straightening, heat treat, and secondary machining for holes, threads, and precision faces.

Choose extrusion when your part can be defined by a single cross-section and you need many linear feet or high piece counts with low scrap. It works well for profiles with ribs, channels, and internal cavities that would be expensive to machine.

Tradeoffs: geometry is constrained to constant profile (no varying thickness along length), die cost and lead time can be significant, and tight tolerances often require post-machining. Heat effects in hot extrusion can drive distortion and property variation; cold extrusion can be limited by press capacity and material ductility.

Common Materials

  • Aluminum 6063
  • Aluminum 6061
  • Copper C110
  • Brass C360
  • Low carbon steel
  • Magnesium AZ31

Tolerances

±0.005"

Applications

  • Aluminum heat sink profiles
  • Structural T-slot framing extrusions
  • Window and door frame profiles
  • Cable tray and wireway channels
  • Hydraulic cylinder tube stock
  • Automotive seat track rails

When to Choose Extrusion

Extrusion fits parts that are long with a constant cross-section and where the cost can be amortized over medium to high volumes or long run lengths. It’s a strong choice when material utilization matters and the profile can be produced near-net with minimal machining. Plan on secondary ops when you need tight positional features, end geometry, or non-profile details.

vs Forging

Choose extrusion when the part is primarily a constant cross-section profile and you want efficient material usage with minimal flash and trimming. Forging is better for 3D near-net shapes with varying section and localized features; extrusion is better for continuous lengths that you cut and finish.

vs Stamping

Choose extrusion when you need a rigid 3D profile (channels, hollows, ribs) rather than a 2D flat pattern. Stamping excels at thin-sheet parts with bends and punched features; extrusion makes thicker, structural profiles but usually needs secondary operations for holes and end features.

vs Wire Forming

Choose extrusion when the part needs a non-round, structural cross-section or internal cavities that wire can’t provide. Wire forming is ideal for spring-like geometries from round wire with tight bend control; extrusion delivers consistent profiles that are later cut and machined.

vs CNC Machining

Choose extrusion when the profile can be made near-net and you want lower cost per part at volume with less material removal. CNC machining is better for variable cross-sections and complex 3D features; extrusion reduces machining to localized ops like drilling, tapping, and end milling.

Design Considerations

  • Keep the cross-section constant along the full length; handle length-specific features with secondary machining
  • Use generous internal and external radii; sharp corners increase die wear and raise extrusion force
  • Avoid large wall-thickness differences in the same profile to reduce distortion, sink, and uneven metal flow
  • Specify realistic critical tolerances and datums; reserve tight positional requirements for post-machined features
  • Call out straightness, twist, and bow requirements explicitly for long parts; they drive stretching/straightening steps
  • Design for cut-to-length and end finishing: add machining allowances and define end-face requirements for quoting