01What makes a process special
A special process is one whose output cannot be readily or economically verified by subsequent inspection. Welding, heat treatment, casting, plating, painting, bonding, soldering and injection moulding are typical examples. ISO 9001 requires such processes to be validated and periodically revalidated.
02The control elements
- Qualified procedure with defined parameter windows
- Qualified equipment: furnace surveys, calibrated instruments
- Qualified personnel
- Monitoring and recording of parameters for each batch
- Periodic tests on coupons or samples
- Requalification after changes
03Sector assessments
Automotive uses AIAG CQI special process assessments (for example CQI-9 heat treatment, CQI-11 plating, CQI-12 coating, CQI-15 welding). Aerospace may require Nadcap accreditation. Welding uses ISO 3834.
04Outsourced special processes
Many suppliers outsource heat treatment and coating. The main supplier remains responsible. Ask for the sub-supplier list, approval records, process specifications and batch records, and visit critical sub-suppliers.
Published 2026-11-08 · QUALITAS TR technical team