Acceptance
Quality
Level

Acceptance Quality Level (AQL) is a statistical concept used in quality control and inspection processes. It refers to the maximum percentage of defective items that can be considered acceptable in a batch or lot of products.

Purpose:

AQL helps determine the number of samples to inspect and the criteria for accepting or rejecting a batch of goods.

• Sampling: Instead of inspecting every item, AQL allows for statistical sampling, saving time and resources.


• Scale: AQL is typically expressed as a percentage or ratio. For example, an AQL of 1% means that no more than 1% of the items in a lot can be defective for it to be accepted.


• Risk balance: It balances the risk between the producer (risk of rejecting good batches) and the consumer (risk of accepting bad batches). Industry standards: Different industries and product types may have different standard AQL levels.


• Inspection levels: AQL is often used in conjunction with different inspection levels (e.g., normal, tightened, or reduced) to adjust the stringency of inspection based on the supplier's history.

Inspection Levels :

• General Inspection Levels (I, II, III) : Level II is standard, I requires less inspection, III more rigorous


• Special Inspection Levels (S-1 to S-4) : Used for specific tests or when smaller samples are needed

• Critical: Defects that could harm users or violate regulations


• Major: Defects likely to result in product failure or significantly reduce usability


• Minor: Defects that don't affect function but might influence customer satisfaction .