Acceptance quality limit is the abbreviation of acceptance quality limit, that is, the average quality level of the worst process that can be allowed when a continuous batch is sent for inspection.
AQL is widely used in product quality testing in various industries, and different AQL standards are suitable for testing different substances. In AQL sampling, the number of samples is the same. The smaller the value after AQL, the fewer defects are allowed, indicating that the higher the quality requirements, the stricter the inspection.
sample survey
Batch range, inspection level and AQL value determine the number of samples and the number of qualified and unqualified products. Clothing quality inspection adopts sampling scheme. The AQL of clothing batch is 2.5, the inspection level is general inspection level, and the inspection strictness is normal inspection. The sampling scheme is shown in the table:
Normal inspection sampling scheme (AQL-2.5)AQL is the abbreviation of-acceptance quality limit and is an international standard. AC = acceptable number = use the first value below the arrow = use the first value above the arrow.
Sampling inspection method
The number of unit products (sample size or series sample size) to be inspected in each batch and a specific batch acceptance standard scheme (including the number of products received, the number of unqualified products, the decision rules, etc.). ) is specified.
sampling method
1, simple random sampling method; Everyone has the same chance, similar to the familiar lottery.
2. Systematic random sampling method; (equidistant or mechanical)
3. Stratified sampling method; (Simple random sampling is conducted according to product characteristics, such as: safety, serious and extremely serious sampling is divided into three times)
4. Grouping sampling method. (grouping)
Quality level (AQL, PRQ, LQ, RQL, AOQ, AOQL), inspection level (IL) and batch number N are usually the important parameters of retrieval sampling scheme when making statistical sampling inspection scheme by using national standards. The rules or principles for selecting inspection level (IL) and batch number (N) are generally clear and easy to master.
The selection of quality level is the focus of attention of both producers and users, which involves quality control, production management and marketing strategy. It is related to the theory and practice of statistical inspection, and there are many clues that are difficult to grasp.