AQL - Acceptable Quality Level
This is usually defined as the worst case quality
level, in percentage or ratio, that is still considered acceptable.
QA, (Quality Assurance), may
be in charge of monitoring AQLs'.
If a produced unit can have a number of
different defects, then demerits can be assigned
to each type of defect and product quality measured in terms of demerits.
As an AQL is an acceptable level, the probability
of acceptance for an AQL lot should be high. (Typical values between
92.74% to 99.999996% for six sigma, see
Cpk
compares to PPM for value reasons)
Some sources characterize an acceptable
quality level as the highest percent defective
that should be considered reasonable as the process average.
Usually monitored using SPC,
(Statistical Process Control), at the production levels by Quality
inspection.
Standard military sampling
procedures, (MIL-STD), have been used for over 50 years to achieve
these goals. The MIL-STD defines AQL as...
"the
maximum percent defective (or the maximum number of defects per hundred
units) that, for purposes of sampling inspection, can be considered
satisfactory as a process average."
For more information on MIL-STD see Choosing
a Sampling Plan: MIL Standard 105D.
Also see RQL
- Rejectable quality level
