What quality control measures should fabricators implement to ensure curtain wall extrusions meet dimensional tolerances?

Quality control for curtain wall extrusions begins at material receipt and continues through extrusion, machining, finishing, and assembly. Fabricators should require mill certificates for aluminium alloy and temper, inspect incoming extrusions for straightness, surface defects, and dimensional conformance using calibrated calipers and profile gauges, and document acceptance criteria. CNC machining centres and jigs must be calibrated and periodically checked with master gauges to ensure hole positions and slot tolerances meet shop drawings and anchor templates. Implement first article inspections for new profiles and production lot sampling using a documented inspection plan and coordinate measurement against CAD nominal dimensions with tolerance bands tied to project specifications. Use statistical process control (SPC) to monitor critical dimensions and flag drift before nonconforming parts are produced. Surface finish control—anodising or powder coating—requires post-finish dimensional checks as coatings can alter fit; adjust tolerances to account for coating thickness. Maintain traceability with batch codes and retention samples for each lot. Fabricators should run assembly trial fits and full-scale mock-ups to confirm fit-up and identify tolerance stack-ups between components. Provide documented measurement reports and non-conformance procedures, and require subcontractors to follow the same QC regime. Finally, ensure the production facility meets relevant quality management standards such as ISO 9001 and that the workforce is trained in inspection routines, which reduces installation delays and maintains façade performance.