1. Basis for determining the sampling quantity of AQL:
1. Engineering method: The engineering method takes the technically necessary quality as AQL according to the product performance, service life, interchangeability, assembly, safety and other quality requirements.
2. similarity method: there is no historical data on the quality of new products, and the AQL value of similar products (raw materials, structure, technology, etc.) can be referred to for determining the AQL value.
3. empirical method: the personnel in charge of the department, engineers and technicians, and quality management personnel shall determine the AQL according to the process capability and other experiences.
4. experimental method: the experimental method is to temporarily assign an AQL value without any bright information for reference, and then adjust the AQL according to the relevant quality information obtained during use.
5. Inverse deduction method: instead of directly specifying the AQL value, the inverse deduction method finds a normal inspection sampling scheme, so that its OC curve passes through an important point with low receiving probability, such as the indifference point (the control point of OC curve) and the user's risk point, and deduces the required AQL value.
second, there is no relationship between the quantity of AQL sampling and the quantity of batch delivery and receipt, because AQL sampling refers to the average quality level of the worst process that can be allowed when a continuous batch is submitted for acceptance.
third, the batch range, inspection level and AQL value determine the number of samples and the number of qualified and unqualified products. The sampling quantity is based on the general inspection level II.
AQL.1~.1 is tested by electronic products and medical devices. AQL1.~6.5 is used for inspection of clothes and textiles. The number of samples refers to a sampling parameter, which is generally used in batch production, and the parameter table for inspectors to sample randomly and check whether it is qualified or not.
Extended data:
1. Sampling method of AQL:
1. Simple random sampling method; (Each individual has the same opportunity, similar to lottery)
2. Systematic random sampling method; (equidistant or mechanical)
3. Stratified sampling method; (Simple random sampling is carried out according to the characteristics of products, such as: safety, serious and extremely serious sampling is divided into three times)
4. Grouping sampling method. (divided into groups)
2. Precautions for AQL sampling:
1. Consider the use of products and the consequences caused by product failure. For example, the AQL value of electronic components of the same specification can be larger when used in general civilian equipment than when used in military equipment; The AQL value for ordinary instruments can be larger than that for precision instruments.
2. Although AQL is not a requirement for the quality of individual batches, if it is really known that the number of unqualified products per 1 units of a batch of products (or the number of unqualified products per 1 units) does not exceed the specified AQL value, the batch should be accepted; Otherwise the batch shall be rejected.
3. From the user's point of view, the AQL value should not be too small, otherwise, the inspection fee and product cost will increase, or the product batch is often rejected, so that the supplier refuses to sign the contract.
4. If the quality of the products urgently needed by the users is difficult to improve for a while, the AQL value has to be appropriately larger in order to obtain the products, and the AQL value will be adjusted after the quality of the producers is improved.
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