AQL Sampling Plan Query
ANSI/ASQ Z1.4 Acceptance Sampling
Input Conditions
0.65=Tight (critical) | 1.0=Normal | 2.5=Loose | 4.0=Cosmetic
Level I=Reduced | II=Normal (default) | III=Tightened
AQL Selection Guide
• 0.65：Safety-critical parts, medical devices
• 1.0：Mechanical functional parts
• 2.5：General industrial parts (most common)
• 4.0：Cosmetic parts, packaging
Purchasing receives a 5000-pc delivery from a supplier. Following ISO 2859-1, QA enters the lot size, AQL level, and inspection level; the tool looks up the sample size (n) and accept/reject numbers (Ac/Re), turning the sampling-plan decision into a one-minute task.
Lot N = 5000 pcs, AQL = 1.0%, general inspection level II. Code letter: L. Sampling plan: n = 200, Ac = 5, Re = 6. Sample 200 pcs; accept the lot if defectives ≤ 5, reject if ≥ 6 and require the supplier to 100% screen and resubmit.
FAQ
Related Tools
Acceptance Sampling Plan
The AQL lookup gives standardized sampling plans; the acceptance sampling tool lets you customize n and c and plot OC curves to evaluate acceptance probability at various defect rates.
Open toolProcess Capability Index
Higher process capability (CPK) allows a less stringent AQL. Regularly verifying supplier CPK is a key basis for setting sampling stringency.
Open toolControl Plan
AQL sampling parameters (sample size, acceptance number, frequency) should be formally documented in the control plan as the standard basis for the quality system.
Open tool