Streaking

Problem Description

• Excessive billet temperature
  Cause in: Equipment

  Corrections

  • Reduce billet temperature

    Advantage: Improves quality of extrusion.
    Disadvantage: Reducing billet temperature may decrease production.
• Grain size variation (galvanizing)
  Cause in: Die, Profile, Equipment

  Corrections

  • Adjust ports and/or bearing transitions.

  • Evaluate billet temperature.

  • Redesign profile with customer interaction.

• Oxide
  Cause in: Die, Profile, Equipment

  Corrections

  • Evaluate for proper step behind bearing and mill/grind as required (should be approximately 1mm except for critical support areas).

  • Restrict port openings, ensure port entry is within maximum circumscribed circle on port entry chart.

  • Evaluate for dead metal zones in ports and weld chambers, and modify as needed.

  • Check container liner for belly and replace/repair.

  • Check dummy block for wear or damage and repair/replace.

  • Inspect die slide/container alignment, adjust as required.

• Poor blending of bearing changes
  Cause in: Die

  Corrections

  • Ensure bearing changes are located in correct areas; blend bearing transition; square bearings perpendicular to die face, flatten bearings perpendicular to flow.

    Advantage: Easy to accomplish with long term benefits
• Profile design
  Cause in: Profile

  Corrections

  • Redesign with customer interaction.

    Advantage: Best for long term results.