What is Extrusion?
Extrusion is the process of forcing a material through a mask nozzle under high pressure, creating rails with a very detailed, linear, cross section profile. The rails can then be cut into individual slices or pieces or processed further.

How Does Extrusion work?
The raw material is usually cut into logs or rails, heated, and then forced through the mask. Depending on the complexity of the desired cross section profile, relatively long tunnel masks or several mask steps are used. The rails are then cooled, cut, hardened and optionally undergo further post processing or refining steps.

Advantages:
  • Very cost efficient
  • Short lead-time
  • very complex cross-section within 1 step
  • Very smooth surface texture without post-processing
  • Can be used to create large components
  • Can be welded/soldered

Disadvantages:
  • Cross section and surface need to be linear
  • Irregular shapes need post-processing (CNC)
  • large shear forces cause the metal to be under inner tension
  • metal contains microscopic faults and structure variations that influence thermal conductivity



Comparison
Die casting
Extrusion
Stacked fin
Folded fin
Skived fin
Cost
medium to low
low
high
medium
low
Tooling Lead-Time
long
short
long
long
medium
Weight
medium
heavy
light
light
medium
Performance
high
limited
best
medium
limited