Tolerances and Mechanical Property Limits

Extrusion Tolerances

Applicable manufacturing tolerances are those set out by the Aluminium Development Council of Australia Ltd (ADCA) in Aluminium Standards, Data and Design: Wrought Products (First Edition 1994). Invariably, tolerances for an individual geo-metric shape are subject to negotiation and agreement between extruder and customer. Under this provision, the function of the shape in its specific application is given priority consideration. All manufacturing tolerances are subject to review from time to time.

  1. Dimensional tolerances are rounded down to the nearest 0.05mm, because all callipers used to measure metal dimensions are almost universally graduated at intervals at 0.05mm.
  2. Metal dimensions refer to solid metal dimensions or any measurement unbroken by a gap or void. For tolerances across gaps or voids refer to the ADCA standards.

Useful formulae

Nominal mass (kg/m2) of Extruded Aluminium: calculate cross-section area (mm2) and multiply by 0.00271

Factor ( Difficulty of Extrusion factor) - calculate the perimeter of the section ( for hollow sections, both outside and inside perimeters) and divide the result by the nominal mass (kg/m) of the section.

Weight of Billet: Billet, 178mm diameter 1mm = 0.0666 Kg. Billet, 202mm diameter 1mm = 0.0875Kg