The sampling schemes defined in ISO 2859-5:2005 are applicable, but not limited, to the inspection of: end items, components and raw materials, operations, materials in process, supplies in storage, maintenance operations, data or records, and administrative procedures.These schemes are designed to be applied to a continuing series of lots, that is, a series long enough to permit the described switching rules to be applied. These switching rules provide: a) enhanced protection to the consumer (by means of tightened sampling inspection criteria or discontinuation of sampling inspection) should deterioration in quality occur; and b) an incentive, at the discretion of the responsible authority, to reduce inspection costs (by means of reduced sampling inspection criteria) should consistently good quality be demonstrated over time.The individual sampling plans are not designed to be applicable outside of the schemes in which they are presented. If lots are produced in isolation or in a series too short for ISO 2859-5:2005 to apply, the user is advised to consult ISO 2859-2 for appropriate sampling plans. Related Products Standard ISO 3951-3:2007: Sampling procedures for inspection by variables - Part 3: Double sampling schemes indexed by acceptance quality limit (AQL) for lot-by-lot inspection ISO 3951-3:2007 specifies an acceptance sampling system of double sampling schemes for inspection by variables for percent nonconforming. It is indexed in terms of the acceptance quality limit (AQL). The objectives of the methods laid down in ISO 3...
In commerce, any negotiation puts buyer and supplier in direct conflict.Footnote 1 Although the exchange of products and services can take place either with legal contracts or as informal agreements promoting the welfare of all participants, the main characteristic of negotiation is the attempt of one adversary to gain more. Even in honest and open negotiations with a relatively free flow of well-defined objectives among all participants, there are still differences between the antagonisms of buyers and sellers. Each adversary is an independent decision maker at least in theory, capable of assuming responsibility for her own decisions. In the commerce of large lots of standardized goods, statistical modeling and the concepts of probability can distinguish between different points of view, recognizing and revealing the conflicts inherent in negotiations. Consequently, to ensure the quality of large lots, each party may require different contractual sampling plans which specify lot size (N), sample size (n) and the maximum number of defective parts (c) in the sample that still allows for lot acceptance, the formal symbols are PL(N, n, c).
Along the OCC, the pair of values LTPD and P(LTPD) signifies a single point. There are several configurations of PL(N, n, c) compatible with a given pair of values for LTPD, P(LTPD), each configuration producing different shapes for the OCC. The choice of configuration, in practice, is not as free as it seems. Technology and the commercial terms of the negotiation usually impose lot size N. The value of c usually does not flee too far from zero. In the end, only sample size n remains unknown. We discuss this question further in what follows.
AQL is a robust statistical model that has been used very successfully over many years. However, an AQL inspection will not guarantee a defect-free experience as some defects will go undetected. AQL will simply allow you to select the percentage of defects that you are willing to accept and can be a sensible option when it comes to gaining valuable insights about your products in your supply chain. 1e1e36bf2d