LED Quality Inspection & AQL
Sampling plans and inspection points.
1. Why it matters
AQL-based inspection turns "the goods look fine" into a defensible pass/fail decision on a statistical sample. For LED products it must cover three layers — safety, function and photometrics — because a luminaire can look perfect and still be 15% under its rated lumens or fail a HiPot test.
2. Sampling: how AQL works
Under ISO 2859-1, the lot size and inspection level (usually General Level II) set the sample size, and the AQL sets the accept/reject number. For a 3,200-unit lot at Level II the sample is 125 units; at AQL 2.5 the lot passes with up to 7 major defects and rejects at 8.
- Critical (safety): AQL 0 — none allowed.
- Major: AQL 2.5 for general commercial goods.
- Minor: AQL 4.0 (cosmetic within tolerance).
3. LED-specific test points
| Layer | Test | Pass criterion |
|---|---|---|
| Safety | HiPot (dielectric), earth continuity | No breakdown at rated test voltage |
| Function | Power-on, dimming, flicker | Works across dimming range; low flicker |
| Photometric | Lumen, CCT, CRI spot check | Within ±10% lumens; CCT in bin |
| Durability | Ageing / burn-in sample | No early failures in the sample |
4. Report contents to demand
A useful inspection report is evidence, not a checkbox. Require lot and sample sizes, the AQL result per defect class, measured photometric values, HiPot results, and dated photos of any defects found — enough that you could defend the decision to your finance team.
5. Checklist
- Set inspection level and AQL per defect class in advance
- Require HiPot and earth-continuity on the sample
- Spot-check lumens/CCT/CRI against the datasheet
- Demand measured values and dated defect photos
- Agree the remedy for a failed lot before production