This standard specifies the method for developing and using general control charts. GB/T 6381-1986 General Control Charts GB/T6381-1986 Standard download decompression password: www.bzxz.net
This standard specifies the method for developing and using general control charts.

1 Introduction
National Standard of the People's Republic of China
Universat control chart
Universat control chart
UDC 519.283:658
GB 638186
This standard specifies the method for developing and using universal control charts. Universal control charts are used to standardize the controlled statistical products, with the zero line as the center line and ±3 as the upper and lower control limits. It is equivalent to the conventional control chart of the original statistical product under control, and is mainly used in situations where the sample sizes are unequal. This standard uses U to represent the new statistic after standardization, referred to as the standard statistic, which can be expressed as: L/=statistic - mean of statistic
standard deviation of statistic
In practical applications, the mean and standard deviation of the statistical base can be used with corresponding estimated values. Other terms and symbols are consistent with the provisions of GB4091.1~4091.9-83 "Gauge Control Chart". 2 Types of general control charts
The general control charts and their statistics corresponding to the original statistical control charts are shown in Table 1. Since the number of defective products and the defective product rate are equal in the general control chart, the general defect number chart is used, and the number of defects and the number of unit defects are equal, so the general defect number chart is used. 3 Schematic diagram of general control chart
The horizontal axis of the general control chart represents the sample number or sampling time, and the vertical axis represents the standard statistic. There are seven horizontal lines on the chart, U=0, ±1, =2, ±3, where =0 is the center line C1 of the general control chart, and U=±3 are the upper and lower control limits UC1 and LCL of the general control chart respectively. If there are sufficient reasons to show that other control limits are more appropriate, U values ​​not equal to ±3 can also be used as control limits.
The center line of the general control chart is a thick solid line, the upper and lower control limits are dotted lines, and the remaining horizontal lines are thin solid lines, see Figure 1. ucl
National Bureau of Standards 1986
05-13 released
Figure 1 General control diagram
Implementation on 1987-05-01
6381—86
Style King
@/33 =n
In the formula
-uduan+up
erpn-p=
Sd-1) dydu-p)=n
In the code!
In plastics manufacturing
Charts for direct plotting on general control charts 1 Direct plotting table and U-curve chart for direct plotting GB 8381-86
In order to make it possible to plot points on site without calculation, it is necessary to pre-calculate the statistical values ​​corresponding to =0, +1, ±2, =3 according to the formula in column (6) of Table 1 and the value of the selected sample size, and draw a direct plotting table (see Table 2 for the format), or draw a U-curve chart for direct plotting (for example, Figure 2 is an example of a U-curve chart of the general non-conforming number chart) for on-site plotting. 2 Direct plotting table
Statistical road
Sample technique female
Figure 2 Line graph
GB 6381—B6
4.2 Use of direct plotting table and U curve chart According to the statistical plate of random samples (such as, d, etc.) and sample size, the value of the standard statistic U corresponding to the statistic can be found from the direct plotting table or U curve chart, so as to determine the plotting position on the universal control chart. For example, if a statistic is between the curve U=0 and =1 in the U curve chart, it is also in the corresponding position between the horizontal line =0 and U=1 on the universal control chart. bZxz.net
Preparation work, use steps and judgment criteria of universal control chart before use 5
According to the relevant provisions of 6, 7 and 8 in GB4091.1. 6 Examples
6, 1 Example 1 - Universal control chart for analyzing production process A factory intends to use the defective product control chart for quality control of the production process. Try to make a general control chart for analysis and analyze the production process.
Drawing steps:
Collect preliminary data and obtain Table 3.
According to the data in Table 3, n=55～100, 10,000=.0389, substitute into formula (10) in Table 1 to obtain Table 4 (direct plotting table) or Figure 3 (U curve chart)
According to the direct plotting table or U curve chart, determine the plotting points of various samples in the table. (3)
For example, for sample No. 1 (n=85, -2), it can be found in the column of Table 4n-85 that the d corresponding to U= is 3.3 and the d corresponding to L/=-1 is 1.5. Since d=2 is between these values ​​and is closer to the latter, its plotting point position on the general control chart is between the half-water horizontal line U-0 and /=-1 and is closer to the U=-1 line. In the same way, it can be determined that sample No. 27 exceeds the upper control limit U=+3.
Sample sequence
Sample size
Number of defective products
Sample sequence number
Sample size
Number of defective products
For example, the sampling data table in Table 3
En=2315
The points that can be plotted are [
] The corresponding results can also be obtained from the curve graph in Figure 3. For example, the plotted point position of sample No. 1 (n=85, d=2) is at the corresponding position between the half-horizontal lines = and =1 on the general control chart: and the plotted point position of sample No. 27 (1=99, d-10) on the general control chart exceeds the upper control limit as can be seen from point 27 in Figure 3. The same applies to the remaining points, and the general control chart of Figure 4 can be drawn. Analysis and judgment: (1) Figure 4 shows that samples No. 5 and No. 15 are located below the center line for ten consecutive points, and the points of sample No. 27 exceed the upper control limit. It can be seen that the production process is not yet in a controlled state, so the control chart used for analysis cannot be converted into a control chart for control (see 8.4 of GB 4091.1--83)
Example 1 Directly plot the point table
, in the table "the number before d indicates that d is negative, and the constant value is not listed. 7.2
GB6381-86
= - 2
Staircase size"
Figure 3 Curve chart used for plotting points in Example 1
《2）Figure 4 also shows that it is possible to reduce the average defective rate of the process to below 0.0389 by adjusting the relevant factors of the production process.
Sample technique!
Figure 4 General defective crystal effect diagram of Example 1 26
6. 2 Example 2-
GB 6381--86
Universal control chart for controlling production process According to the existing data, the production process of a certain product is basically in a controlled state, and its half-mean unit defect number is 10.97. Therefore, it is decided to use a universal defect number chart to control the production process. Drawing steps:
(1) According to u=10.971, the daily inspection sample fire mouth is 6~15, and the formula (12) in column (6) of Table 1 is used to calculate Corresponding to the c values ​​of U = 0) ± 1, = 2, ± 3, make a direct plot table (Table 6) or a plot U curve (Figure 5). Table 5 Direct plot table for Example 2
The data of the sampling inspection are shown in Table 6.
Sample number
Sample tree size
Number of missing
Sample student number
Sample size
Number of missing
6 Sampling data for Example 2
GB 638186
（3）Use the self-drawing point table or the point graph to determine the position of each point in Table 6. Figure 6 is the general defect number control chart.
Judgment and treatment
According to 7.2 of GB4091.1～83, it is determined that the production process on the 27th is not in a controlled state: measures should be taken. Identify and eliminate the abnormal reasons that lead to quality decline. Make it no longer correct. 200
Additional instructions:|| tt||Size of wood
Chart of plotting points in Example 2
1121314
252627
Figure 6 General defect count control chart in Example 2
This standard was proposed by the National Technical Committee for Standardization of Statistical Methods Application. 15
This standard was drafted by the working group of the Technical Committee on Statistical Methods Application of the National Technical Committee for Standardization of Statistical Methods Application in Quality Management. Technical standards should be read by ordinary people.
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