- How many samples should be inspected?
- Where is the limit between acceptability and refusal, when it comes to defective products?
Definition and application of 'AQL'
- 0% for critical defects (totally unacceptable: a user might get harmed, or regulations are not respected).
- 2.5% for major defects (these products would usually not be considered acceptable by the end user).
- 4.0% for minor defects (there is some departure from specifications, but most users would not mind it).
- The 'lot size'. If you ordered different products, the quantity of each product is a lot size, and separate inspections should be carried out for each lot. If you ordered only one product, the lot size is your total order quantity.
- The inspection level. Different inspection levels will command different number of samples to inspect. In this article, we will stick to the so-called "level II", under "normal severity".
- The AQL level appropriate for your market. If your customers accept very few defects, you might want to set a lower AQL for both major and minor defects.