Quality Level - AQL
Quality Level. AQL . Also known as Assured Quality Level.
This publication establishes lot or batch sampling plans and
procedures for quality inspection by attributes. The sampling
plans described in this standard are applicable to AQL of
0.01 % or higher and are therefore not suitable for applications
where quality level in the defective parts per million range
cab be realized.
These plans are intended primarily to be used for a continuing
series of lot or batch. The plan may also be used for the
the inspection of isolated lot or batch.
- AQL Keyword listing
Quality Level - AQL - What is AQL?
When a continuous series of lots is considered, the AQL is
the quality level which, for the purposes of sampling inspection,
is the limit of a satisfactory process average.
A sampling plan and an AQL are chosen in accordance with the
risk assumed. Use of the value of AQL for certain defect or
group of defects indicates that the sampling plan will accept
the great majority of the lot or batch provided the process
average level of percentage defective in these lot or batch
be no greater than the designated value of AQL sampling plan.
outgoing quality - AOQ
For a particular process average, the AOQ is the average quality
of outgoing product including all accepted lot or batch, plus
all rejected lot or batch after the rejected lot or batch
have been effectively 100 % inspected and all defectives replaced
Classification of Defects
A classification of defects is the enumeration of possible
defects of the unit of product classified according to their
Lot or batch
The term lot or batch shall mean " inspection lot "
or " Inspection batch " . The lot or batch size
is the number of units of product in a lot or batch.
The process average is the average percent defective or average
number of defects per hundred units of product committed by
the supplier for original inspecting. Original inspection
is the first inspection of a particular quantity of product
as distinguished from the inspection of product which has
been resubmitted after prior rejection.
A sample consists of one or more units of product drawn from
a lot or batch, the unit of the sample being selected at random
without regard to their quality. The number of units of product
in the sample is the AQL sample size.
A sampling plan indicates the number of unit of product
from each lot or batch which are to be insppected and the
criteria for determining the acceptability of the lot or batch.
The unit of product is the thing inspected in order to determine
its classication as defective or non-defective or to count
the number of defects. It may be a single article, a pair,
a set, a length or the end product itself. The unit of product
may or may not be the same as the unit of purchase, supply
Sampling plans | Master table
acceptablle quality sampling plan