AQL inspection: what it is and how to read the report before paying the balance
How AQL sampling works, how many pieces are checked depending on the order size, which defects are accepted and what to do if the inspection fails.
Supro Group team
Before paying the balance of an order in China, the usual practice is to inspect the finished goods. But nobody checks 10,000 pieces one by one: a sample is checked, and clear rules decide whether the lot is accepted or not. Those rules have a name: AQL.
What AQL means
AQL (Acceptable Quality Limit) is a sampling method defined in the ISO 2859-1 standard, equivalent to ANSI/ASQ Z1.4. Based on the lot size, it tells you how many pieces to check and how many defects are allowed in that sample. If more are found, the lot fails.
For consumer goods, general inspection level II is almost always used, with three limits, one for each type of defect:
- Critical defects: 0. The product is unsafe or illegal; none are accepted.
- Major defects: AQL 2.5. The product fails or the customer would return it.
- Minor defects: AQL 4.0. A small flaw that does not prevent use.
How many pieces are checked
| Order size | Pieces checked | Max. major defects (AQL 2.5) | Max. minor defects (AQL 4.0) |
|---|---|---|---|
| 281 – 500 | 50 | 3 | 5 |
| 501 – 1,200 | 80 | 5 | 7 |
| 1,201 – 3,200 | 125 | 7 | 10 |
| 3,201 – 10,000 | 200 | 10 | 14 |
| 10,001 – 35,000 | 315 | 14 | 21 |
Example: in an order of 5,000 pieces, 200 are checked. If 10 or fewer major defects are found (and 14 or fewer minor ones, and no critical ones), the lot passes. With 11 major defects, it fails.
What is checked besides the sampling
- Quantity produced and packed.
- Packaging, carton markings, labels and barcodes.
- Comparison with the approved sample: color, materials, logo, finish.
- Dimensions and weight.
- Function tests depending on the product, and a carton drop test.
How to read the report
A good report has a clear result (pass, fail or pending), the quantity checked, the details of each defect with a photo and classification, and the measurements taken. Read the major defects first: they tell you whether the problem is isolated or systematic. A single scratch is not the same as a logo misprinted on every piece.
If the inspection fails
- Don't pay the balance yet.
- Agree on the correction with the factory: rework, 100% sorting or replacement of the defective pieces.
- Ask for a re-inspection after the correction.
- If the defect is minor and the deadline is tight, you can accept the lot with a discount agreed in writing.
Define the AQL limits and the points to check in the proforma invoice, before production. That way nobody argues about the rules later.
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