The AQL, or Acceptable Quality Limit is the lowest level of satisfactory production upon inspection. Similar terms are rejectable quality limit and rejectable quality level (RQL). The AQL is calculated using a control chart or table that defines the number of samples to inspect and the maximum number of allowable defects. This method is commonly used by inspectors and suppliers in international trade and has proven an effective method for quality control in outsource manufacturing.
Why do buyers need to set an AQL?
In most product categories, there will be defective products in every batch. Even if the manufacturer inspects every good produced, visual inspection does not fully test functionality. In the majority of buyer/supplier relationships, the supplier is not expected to provide 100% defect free batches of goods. Therefore it is up to the buyer to control the quality of the goods. In order to do this the buyer must be able to clearly express the number of defective products which would define a batch as “unacceptable.” This way the buyer and supplier can set a measurable and agreeable limit between acceptability and refusal.
What to consider when setting your AQL
When it comes time to set your AQL, you should consider three things:
- The lot size
The quantity of every product that is being produced is referred to as the lot size. If only one product is being produced the lot size is equal to the total batch quantity.
- The inspection level
The inspection level represents the “severity” of the defects. For some products, a slight variation is not considered a defect, while others require complete uniformity.
- Your market
Some products are expected or understood to come with slight variation and defects, while others will not even be considered a buying option if there is any sort of defect. Depending on your product and your market, you will have to adjust your AQL accordingly