1 Scope
This part of GB/T 2828 specifies sequential sampling schemes that supplement the GB/T 2828.1 acceptance sampling system for inspection by attributes.
The GB/T 2828.1 acceptance sampling system is indexed in terms of the acceptance quality limit (AQL). Its purpose is to induce a supplier, through the economic and psychological pressure of lot non-acceptance, to maintain a process average at least as good as the specified acceptance quality limit, while at the same time providing an upper limit for the risk to the consumer of accepting the occasional poor lot.
The sampling schemes defined in this part of GB/T 2828 are applicable, but not limited, to the inspection of:
——end items,
——components and raw materials,
——operations,
——materials in process,
——supplies in storage,
——maintenance,
——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 switching rules in 10.3 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,
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 used outside of the schemes in which they are presented. Where lots are produced in isolation or in a series too short for this part of GB/T 2828 to apply, the user is advised to consult GB/T 2828.2 or GB/T 8051 for appropriate sampling plans.
2 Normative References
The following document is essential for the application of this Standard. For dated references, only the edition cited applies. For undated references, the latest edition (including any amendments) is applicable to this document.
GB/T 2828.1-2003 Sampling procedures for inspection by attributea-Part1:Sampling schemes indexed by acceptance quality limit(AQL) for lot-by-lot inspection (ISC)2859-1:1999, IDT)
GB/T 3358.2-2009 Statistics—Vocabulary and symbols—Part 2:Applied statistics (ISO 3534-2:2006, IDT)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
inspection
conformity evaluation by observation and judgment accompanied as appropriate by measurement, testing or gauging
[GB/T 3358.2]
3.2
original inspection
inspection of a lot, or other amount, not previously inspected
NOTE This is in contrast, for example, to inspection of a lot which has previously been designated as not acceptable and which is submitted again for inspection after having been further sorted, reprocessed, etc.
[GB/T 3358.2]
3.3
inspection by attributes
inspection by noting the presence, or absence, of the characteristic(s) in each of the items in the group of consideration, and counting how many items do, or do not, possess the characteristic(s), or how many such events occur in the item, group or opportunity space
NOTE When inspection is performed by simply noting whether the item is nonconforming or not, the inspection is termed inspection for nonconforming items. When inspection is performed by noting whether the number of nonconformities on each unit, the inspection is termed inspection for number of nonconformities
[GB/T 3358.2]
3.4
item
anything that can be described and considered separately
EXAMPLES A discrete physical item; a defined amount of bulk material, a service, activity, person and or some combination thereof.
[GB/T 3358.2]
3.5
nonconformity
non-fulfilment of a requirement
[GB/T 3358.2]
NOTE 1 In some situations, specified requirements coincide with customer usage requirements (see defect, 3.6). In other situations they may not coincide, being either more or less stringent, or the exact relationship between the two is not fully known or understood.
