How to use the AQL table: the conditions
Now that we have a clear idea about its definition and role, we should focus on understanding how to use the AQL table.
As a matter of fact, the AQL result is reliable only if certain conditions are rigorously respected during the product inspection.
How to use the AQL table: certain conditions
To ensure the reliability of the AQL table result, it is compulsory to:
- Avoid mixing references in the same AQL table
Each product is coming from a different production process therefore they should be controlled independently.
- Perform a random sampling on the total quantity
It is compulsory to pick the finished goods sampling for inspection randomly within the whole lot.
- Follow the “square root” rule
The number of cartons which samples should be drawn from is based on a mathematical method: the square root of the sum of all cartons.
- Define what is acceptable and what is unacceptable for the buyer
The buyer should take the time to categorize defects for the result to be the most accurate possible. If the judgment is only based on the QC interpretation the AQL result could be different: failed even if the defects are acceptable for the buyer, or passed even if the defects are unacceptable for the buyer.
- Limit the order quantity per AQL to 50K pcs
- Choose the AQL level II or III
The AQL table is only a statistical tool
To know how to use the AQL table we have to take into account that it is only a statistical tool. The result remains statistical therefore when an AQL is “passed”, the buyer should always keep in mind that the number of defective goods could have been higher, or lower, than if the QC would have checked the whole order quantity.
Due to the numerous conditions to respect and the fact that the AQL table is only a statistical tool, the buyer should always carefully analyse the inspection report received. All the details are important to check, in particular the AQL defect list and pictures. The buyer should also ask himself: are those defects acceptable even if the percentages was higher on the total order?
And you: do you have other recommendations on how to use the AQL table?