Overview
ISO 3269:2019 - Fasteners - Acceptance inspection defines a purchaser’s incoming inspection procedure to be used when no prior agreement with the supplier exists. It provides a reference acceptance procedure for acceptance or rejection of inspection lots of bolts, screws, studs, nuts, pins, washers, rivets and related fasteners. The standard is intended for general-purpose fasteners (not those for high‑volume machine assembly, specially engineered or special‑purpose applications). It complements in‑process inspection standards (see ISO 16426).
Key topics and requirements
- Scope and purpose: A purchaser-led sampling and inspection procedure when supplier/purchaser agreements are absent or disputed.
- Inspection lots: Defined as same designation, supplier and (when available) manufacturing lot number.
- Sampling plans: Sample size is selected based on inspection lot size (Table 1). The standard introduces a layered approach including a small-sample option (N = 0) and uses sampling categories.
- Acceptance criteria: Uses acceptance number (Ac) and rejection number (Re) per characteristic; Category 1 and 2 characteristics typically have Ac = 0 (no non‑conformities tolerated), while Category 3 characteristics allow limited non‑conformities and are linked to ISO 2859‑1 sampling tables.
- Quality indices: Defines AQL (Acceptance Quality Limit) and LQ (Limiting Quality) concepts and links them to operating characteristics of sampling plans.
- Inspection modalities: Purchaser chooses which mechanical, physical, functional and dimensional characteristics to inspect (examples: hardness, tensile strength, drive geometry, dimensions, torque). Destructive tests and non‑destructive tests are treated according to the characteristic.
- Disposition and verification: If non‑conformities are found, procedures for lot disposition and purchaser options (including offering the supplier opportunity to verify) are specified; a reference acceptance procedure is provided when no agreement is reached.
Applications and users
- Practical use: incoming inspection, receiving inspection, lot acceptance/rejection decisions, dispute resolution between purchaser and supplier.
- Typical users: quality engineers, inspection and test laboratories, procurement and purchasing managers, suppliers and manufacturers of fasteners, and compliance officers responsible for incoming material control.
- Benefits: provides a standardized, defensible approach to sampling, reduces ambiguity in supplier disputes, and helps balance inspection effort with product risk.
Related standards
Keywords: ISO 3269:2019, fasteners, acceptance inspection, sampling plan, AQL, incoming inspection, inspection lot, acceptance number (Ac).