Garment Inspection
Jimmy K.C. Lam
The Hong Kong Polytechnic University
Garment Inspection
Stage of Garment Inspection
 AQL Random Sampling Inspection
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– AQL 1.5 severe inspection
– AQL 2.5 normal/good quality inspection
– Sample Size Code Letter
Single Sampling Plan, normal inspection
 Double Sampling Plan, normal inspection
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Stages of Garment Inspection
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Pre-production Check
– final check on the raw material used, style, cut
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Initial Production Check
– First batch of garments is inspected, make
correction before bulk production
During Production Check
 Final Random Inspection
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– Checking the total production quality by selecting
the samples from the order. AQL sampling
inspection may be applied
AQL Random Sampling Inspection
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The AQL inspection takes the samples from a goods,
inspect them and depends on the quality of samples
inspected and decide to accept or reject them.
The standard is based on Military Standard 105D (MILSTD-105D)
It provides with the sampling plans, the number of samples
to be inspected and the acceptable quality level (AQL)
AQL 1.5 is applied to very severe inspection on high-class
expensive item.
AQL 2.5 is applied when textiles of normal/good quality
are involved.
AQL (II)
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Three types of sampling plans
– single, double and multiple
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Each sampling plan can be performed in three
level
– normal, tightened and reduced, depending on
quality of products
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In garment industry, single and double normal
sampling plans are applied
Sample Size Code Letter
The Sample Size Code Letter shows different
lot sizes to different code letter.
 There are seven inspection level, four for
general inspection and three for special
inspection
 For garment inspection, General Inspection
level II would be used.
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Sample Size Code Letter
Single Sampling Plan for normal
inspection
Double Sampling Plans
Example
Single Sampling Plan-Normal Inspection
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Assume AQL is 2.5% and lot size is 600
garments, find out the following :
– The total number of samples need to inspect
– The acceptable number of the samples
– The rejection number of the samples
Answer
Single Sampling Plan
First, from Table 1 find out the code letter for
lot size of 600 and inspection level II is “J”
 From Table 2 (single sampling plan), the letter
“J” corresponds to sample sizes of “80”.
 So, 80 samples are needed to inspect out of 600
 At AQL 2.5%, if defective garments are less
than or equal to 5, whole lots will be accepted,
if it is found to be 6 or more, whole lots will be
rejected.
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Try this one
If the garment lot is 300 dozens, and AQL is
4.0%, find out
 the number of samples to be inspected
 the acceptable number and rejection number
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Example II
Double Sampling Plan
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Assume AQL is 4% and lot size is 2000
garments, find out from double sampling plan
on the following:
– The total sample sizes need to inspect
– What is the first acceptable number
– What is the second acceptable number
Answer
Double Sampling Plan
First, Table 1 of 2000 lots at inspection level II
is letter “K”
 Table 3, double sampling plan shows the sample
size of letter K is 80.
 First inspection, at AQL 4%, the acceptable
number is 5, rejection number is 9
 If any number between 5 to 9, second
inspection is needed
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Answer
Double sampling Plan (II)
For second inspection, the sample sizes again is
80
 At AQL 4%, the cumulated acceptable number
is 12 and rejection number is 13.
 Conclusion
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– If the number of defective garments found in the
first sample is 6, and in second sample is 5,
making a total of 11, then the whole lot of 2,000
pieces will be accepted.
Try this one
Double Sampling Plan
A total of 3,000 dozens of sweaters were
produced. At AQL 2.5%, find out the following
at double sampling plan:
 The total sample sizes need to inspect
 The acceptable number at first inspection
 The acceptable number at second inspection
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