As default, we uses general inspection level II,
special inspection level S1, Acceptable Quality
Level (AQL) 0/2.5/4.0 of critical, major, minor
defect.
For example, we have a lot of 12000 units to
inspect. According to table 1, "M" is
right sample size code for general inspection
level II. Therefore in table 2, we pick "315"
as M's corresponding sample size. So the allowed
maximum number of defective unit is as follows:
Critical Defect 0; Major Defect 14; Minor Defect:
21.
In other words, if the number of critical defective
units is more than 0, or major defective units
is more than 14, or minor defective units is more
than 21, the lot has to be rejected.
How to choice
Level I, Level II, or Level III?
Generally,Level II is used for consumer products,
but if you think the product is expensive and
need check more samples, you can choice Level
III, otherwise you can choice Level I.
How to choice
AQL 2.5, 4.0 or others?
Generally, 0 for Critical,2.5 for Major, 4.0
for Minor. But if you think the product is expensive
and should be checked strictly, you can choice
1.5 or smaller number for Major and Minor, otherwise,
you can choice bigger number. The smaller, the
stricter.
Defect classification
Critical defect
The "Critical Defect" corresponds to
a defect likely to result in unsafe conditions
for end-users or specifically requested by customers.
Major defect
The "Major Defect" corresponds to a
defect at the function, or to reduce the usability
of the unit of product for its intended purpose.
Minor defect
The "Minor Defect" corresponds to a
defect that is not likely to reduce the usability
of the unit of product for its intended purpose,
or is a departure from established standards having
little bearing on the effective use or operation
of the unit. |
