Make · process

Extrusion

A continuous constant cross-section through a die

Polymer is melted and pushed continuously through a shaped die, producing an endless profile of constant cross-section — pipe, sheet, film or fibre — cut or wound to length. It is how most plastic that is sold by the metre or the roll is made.

Very high (continuous)
Volume
Moderate — die
Tooling
Continuous
Cycle
Moderate
Tolerance
How it works
  1. 1
    Melt and pump pellets through a heated barrel and screw.
  2. 2
    Force the melt through a die shaped to the target cross-section.
  3. 3
    Cool the extrudate in a water bath or over chill rolls.
  4. 4
    Pull it away at constant speed, then cut or wind it.
Strengths & limits
Strengths
  • Very high continuous output
  • Low cost per metre
  • Long parts of constant section
  • Co-extrusion layers materials (e.g. a barrier film)
Limits
  • Constant cross-section only
  • Die design and haul-off control are exacting
  • Not for complex 3D shapes
Typical parts & materials

Typical parts: Pipe and tube, window profiles, sheet and film, wire insulation, filament

Commonly run in — open one for its cited properties:

PVCHDPEPPPETPS

Part of the Make map of manufacturing processes. Browse the cited database, or see where these parts end up in the application domains.