GB/T 2829-2002 English PDF (GB/T2829-2002)

GB/T 2829-2002: Sampling procedures and tables for periodic inspection by attributes (apply to inspection of process stability)
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GB/T 2829-2002
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 03.120.30
A 41
Replacing GB/T 2829-1987
Sampling procedures and tables for periodic
inspection by attributes (Apply to inspection of
process stability)
ISSUED ON: JUNE 13, 2002
IMPLEMENTED ON: JANUARY 01, 2003
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine
Table of Contents
Foreword ... 3 
1 Scope ... 4 
2 Normative references ... 4 
3 Terms, definitions and symbols ... 4 
4 Inspection procedures ... 9 
5 Implementation of inspection ... 10 
6 Sampling characteristic curve and average sample number curve ... 20 
Sampling procedures and tables for periodic
inspection by attributes (Apply to inspection of
process stability)
1 Scope
This Standard specifies the primary, secondary, and fifth sampling plans and
sampling procedures based on the rejection quality level (expressed as the
percentage of rejected products or the number of rejected products per hundred
units) as the quality indicator. It is applicable to the inspection for process
stability.
2 Normative references
The provisions in following documents become the provisions of this Standard
through reference in this Standard. For dated references, the subsequent
amendments (excluding corrigendum) or revisions do not apply to this Standard,
however, parties who reach an agreement based on this Standard are
encouraged to study if the latest versions of these documents are applicable.
For undated references, the latest edition of the referenced document applies.
GB/T 3358.1-1993, Terms for statistics. Part I: Terms for general statistics
GB/T 3358.2-1993, Terms for statistics Part II: Terms for statistical quality
control
GB/T 28281), Sampling procedures for inspection by attributes (idt ISO 2859-
1)
3 Terms, definitions and symbols
3.1 Terms and definitions
For the purposes of this document, the terms and definitions defined in GB/T
3358 as well as the followings apply.
1) In the process of revision (it is the revision of GB/T 2828-1987 "Sampling procedures and tables for
lot-by-lot inspection by attributes (Apply to inspection of successive lots or batches)"). It is equivalent
to ISO 28591: 1999.
the important quality characteristics of the unit product do not meet the
regulations, or the quality characteristics of the unit product seriously do not
meet the regulations
3.1.10 Class C rejection
the general quality characteristics of the unit product do not meet the
regulations, or the quality characteristics of the unit product slightly do not meet
the regulations
3.1.11 rejected product
there are one or more rejected unit products; according to the type of rejection,
it can be generally divided into: Class A rejected product, Class B rejected
product, Class C rejected product
3.1.12 Class A rejected product
there is one or more Class A rejection, and there may also be Class B and/or C
rejection unit products
3.1.13 Class B rejected product
there is one or more Class B rejection, and there may also be Class C rejection,
but excluding Class A rejection unit products
3.1.14 Class C rejected product
there is one or more Class C rejection, but excluding Class A and B rejection
unit products
3.1.15 percentage of rejected products
the total number of all rejected products in the batch divided by the batch
number, then multiplied by 100; that is:
Percentage of rejected products = (total number of rejected products in the
batch / batch number) × 100
3.1.16 number of rejected products per hundred units
the total number of rejected products of all units in the batch divided by the
batch number, and then multiplied by 100; that is:
Number of rejected products per hundred units = (total number of rejected
products in all unit products in the batch / batch number) × 100
3.1.17 batch quality
in count acceptance sampling, the minimum number of rejection or rejected
products that are not allowed in samples of a rejected batch
3.1.27 determination array
a combination of determined number of acceptance and determined number of
rejection or determined number series of acceptance and determined number
series of rejection
3.1.28 sampling plan
a specific plan for sample number and relevant acceptance criteria
3.1.29 sampling procedure
a process of using the sampling plan to determine whether the lot is qualified
or not
3.1.30 primary sampling plan
a sampling plan composed of sample number and determination array [Ac, Re]
3.1.31 secondary sampling plan
a sampling plan composed of the first sample number n1, the second sample
number nz, and the determination array [A1, A2, R1, R2]
3.1.32 fifth sampling plan
a sampling plan composed of sample number series n1, n2, n3, n4, n5 and
determination array [A1, A2, A3, A4, A5, R1, R2, R3, R4, R5]
3.1.33 discrimination level
the level of ability to judge the stability of the production process that does not
meet the specified requirements
3.1.34 probability of acceptance
when a definite sampling plan is used, the probability that a batch or process
with a given quality level will be judged as acceptance
3.1.35 average sample number
when a certain sampling plan is used to make a decision of acceptance or
rejection, the average number of samples to be inspected per batch expected
3.1.36 sampling characteristic curve (OC curve)
b) Select test items and form test groups;
c) Specify test methods and quality characteristics;
d) Specify rejection classification;
e) Specify rejection quality level;
f) Specify discrimination level;
g) Select sampling plan type;
h) Search sampling plan;
i) Extract sample;
j) Inspect sample;
k) Determine whether periodic inspection is accepted or rejected;
l) Disposal after periodic inspection.
5 Implementation of inspection
5.1 Provisions on inspection cycle
In the product technical standard or order contract, the inspection period shall
be appropriately specified according to the approximate duration of the product
production process, the test time and the test cost. Usually the inspection period
is one month, two months, three months, half a year, or even one or two years.
In the same product technical standard or order contract, different inspection
cycles are allowed for different test groups.
In addition, it is allowed to specify the inspection cycle according to the quantity
manufactured by product.
5.2 Selection of test items and composition of test groups
In the product technical standard or order contract, the test items shall be
selected according to the actual needs of the product and the possibility of
implementation. Combine these test items into as few test groups as possible.
5.3 Provisions on test methods and quality characteristics
In the product technical standard or order contract, the corresponding test
method shall be specified for each test item. Specify the technical performance,
technical indicators, appearance and other quality characteristics for each
5.7 Selection of sampling plan type
This Standard, in Table 2~Table 4, Table 5~Table 7 and Table 8~Table 10,
respectively gives three types of sampling plans: primary, secondary and fifth
sampling plans. For a given set of rejection quality levels and discrimination
levels, different types of corresponding sampling plans can be used. Usually,
by comparing the management cost, average test time and average sample
number of various types of corresponding sampling plans, it is decided to use
either the primary, secondary or fifth sampling plan. The average sample
number of the fifth sampling plan is smaller than the average sample number
of the corresponding secondary sampling plan (except those corresponding to
the determination array [1,2]). The average sample number of the secondary
sampling plan is smaller than the average sample number of the corresponding
primary sampling plan (see Figure 13~Figure 29). The average test time of the
fifth sampling plan is greater than the average test time of the corresponding
secondary sampling plan. The average test time of the secondary sampling plan
is greater than the average test time of the corresponding primary sampling
plan. In addition, the management cost of the fifth sampling plan is higher than
the corresponding secondary sampling plan. The secondary sampling plan is
higher than the corresponding primary sampling plan.
However, as long as the specified rejection quality level and the discrimination
level are the same, no matter what corresponding sampling plan to the type of
this Standard is used for inspection, its discrimination of whether the stability of
the production process meets the specified requirements is basically the same.
5.8 Search of sampling plan
According to the rejection quality level and discrimination level, search the
sampling plan in Table 2~Table 10.
5.8.1 Search for primary sampling plan
Respectively use Table 2, Table 3 and Table 4 to search the primary sampling
plan of discrimination levels I, II and III.
Search method: In the designated sampling plan table, according to the
affordable test cost and the existing capacity of the test equipment, select an
appropriate sampling plan from a series of primary sampling plans determined
from top to bottom by the specified rejection quality level.
Example 1: Adopt GB/T 2829 in the routine test of an electronic component. Specify RQL=30,
DL=II. Find a primary sampling plan for a certain test group for routine test.
a) Because DL=lI is specified, use Table 4 to search.
b) In Table 4, a series of primary sampling plans are determined by RQL=30 from top to
(3) n1=10, A1=0, R1=3,
n2=10, A2=3, R2=4;
(4) n1=12, A1=1, R1=3,
n2=12, A2=4, R2=5;
(5) n1=16, A1=1, R1=5,
n2=16, A2=5, R2=6;
(6) n1=20, A1=3, R1=6,
n2=20, A2=7, R2=8.
c) If the primary sampling plan has been selected according to the above conditions: n=12,
Ac=1, Re=2, then, according to the correspondence between primary and secondary
sampling plans, from Table 1, it can be immediately determined that the secondary
sampling plan for a certain test group for routine test is: n1=n2=8, A1=0, R1=2, A2=1, R2=2.
5.8.3 Search for fifth sampling plan
Use Table 8, Table 9 and Table 10 respectively for fifth sampling plans of search
discrimination levels I, II and III.
Search method: It can copy the method for primary sampling plan to research.
It can also, according to the one-to-one correspondence (a series of primary
and fifth sampling plans determined by the same RQL from top to bottom are
one-to-one correspondence) between the primary and fifth sampling plans in
Table 2 and Table 8, Table 3 and Table 9, Table 4 and Table 10, search the fifth
sampling plan from the selected primary sampling plan.
It is also possible to determine the fifth sampling plan corresponding to the
primary sampling plan according to the correspondence provided in Table 1.
Example 3: Under the same conditions as in Example 1, find the fifth sampling plan for a certain
test group in a routine test.
a) Because DL=III is specified, use Table 10 to search.
b) In Table 10, a series of fifth sampling plans are determined by RQL=30 from top to bottom:
(1) n=6, Ac=0, Rc=1; 3)
3) There is no corresponding fifth plan.
method to extract samples shall ensure that the samples obtained can
represent the actual technical level of this cycle. When it is convenient, it is best
to take samples from different times of the cycle to form a sample for periodic
inspection. If it is necessary to collect samples at a fixed time, it is best to do it
after the unit product quantity to be manufactured in this cycle exceeds half.
When using secondary and fifth sampling plans, each sample must be taken
for a sufficient quantity at the same time.
5.10 Sample inspection
Before conducting periodic inspection, all sample units shall be inspected for
the items same for lot-by-lot inspection. If the sample unit is found to be rejected,
it shall be replaced by the unit product normally manufactured in this cycle.
Contain this information in the periodic inspection report, but it is not used as a
basis for determining whether the periodic inspection is accepted.
When conducting periodic inspection, it shall be conducted in groups according
to the test items, test methods and sequence specified in the product technical
standard or order contract. After the test, each tested sample unit shall be
inspected one by one according to the technical requirements. Finally, the total
number of rejected products (or rejection) is accumulated by the test group
(when the rejected products are divided into different categories, they shall be
accumulated separately).
5.11 Determination for acceptance or rejection of periodic inspection
5.11.1 Determination method for acceptance or rejection of periodic
inspection
According to the rejection quality level and the sampling plan determined by
discrimination level, use the methods provided in 5.11.2 and 5.11.3 to determine.
Only when all the determined sampling plans are determined to be accepted,
can the product periodic inspection represented by this periodic inspection be
finally determined as accepted. Otherwise, the product periodic inspection
represented by this periodic inspection shall be determined as rejected.
5.11.2 Situation that uses percentage of rejected products to express
batch quality
a) Primary sampling plan
According to the results of sample inspection, the determination is made
according to the following rules.
If the number of rejected products found in the sample is less than or equal
to the number of acceptance, then the batch is determined to be accepted.
second determined acceptance and is also less than the number of the
second determined rejection, then extract the third sample for inspection.
If the sum of rejected products found in the first to third samples is less
than or equal to the ...