qc chapter 4

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CHAPTER 4

ATTRIBUTE CONTROL CHART


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INTRODUCTION

Many quality characteristics cannot be convenientlyrepresented numerically.

In such cases, each item inspected is classified as eitheror to the specifications onthat quality characteristic.

Quality characteristics of this type are called .

Examples are nonfunctional semiconductor chips,warped connecting rods, etc,.


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ATTRIBUTE CHAR.

Attribute char. In quality is referring inmeeting the specification.

Attribute chart is used when:

1. Measurable can not be done

2. measurable constraints

(time, cost & requirement).


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DEFECT & DEFECTIVE

DefectCacat

Damaged unit / product. (nonconforming).

DefectiveKecacatan

Not meeting the standard or requirement /specification. (nonconformities)


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TYPE OF ATTRIBUTE

CONTROL CHART

There are two components;

1. Damaged product (defect-cacat)

2. Not meeting the specifications (defective-kecacatan)


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Attribute Control Charts

This chart shows the fraction of nonconforming or defective product produced by amanufacturing process.

It is also called the control chart for fraction nonconforming.

This chart shows the number of nonconforming. Almost the same as thepchart.

This shows the number of defects or nonconformities produced by a manufacturingprocess.

This chart shows the nonconformities per unit produced by a manufacturing process.


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pChart

CL

UCL

LCL

Sub-

group

Number

Number

Inspected

n

np p

1 300 12 0.040

2 300 3 0.010

3 300 9 0.030

4 300 4 0.013

5 300 0 0.0

6 300 6 0.020

7 300 6 0.020

8 300 1 0.003

19 300 16 0.053

25 300 2 0.007

Total 7500 138


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pChart

Sub-

group

Number

Number

Inspected

n

np p

1 300 12 0.040

2 300 3 0.010

3 300 9 0.030

4 300 4 0.013

5 300 0 0.0

6 300 6 0.020

7 300 6 0.020

8 300 1 0.003

19 300 16 0.053

25 300 2 0.007

Total 7500 138

018.07500

138

n

npp

041.0

300

)018.01(018.03018.0

UCL

0.0005.0

300

)018.01(018.03018.0

LCL


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pChart

Sub-

group

Number

Number

Inspected

n

np p

1 300 12 0.040

2 300 3 0.010

3 300 9 0.030

4 300 4 0.013

5 300 0 0.0

6 300 6 0.020

7 300 6 0.020

8 300 1 0.003

19 300 16 0.053

25 300 2 0.007

Total 7500 138


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npChart

Sub-

group

Number

Number

Inspected

n

np p

1 300 12 0.040

2 300 3 0.010

3 300 9 0.030

4 300 4 0.013

5 300 0 0.0

6 300 6 0.020

7 300 6 0.020

8 300 1 0.003

19 300 16 0.053

25 300 2 0.007

Total 7500 138


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cChart

CL

UCL

LCL


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cChart

ID Number Subgroup c UCL c-bar LCL

MY102 1 7 12.76 5.64 0

MY113 2 6 12.76 5.64 0

MY121 3 6 12.76 5.64 0

MY125 4 3 12.76 5.64 0

MY132 5 20 12.76 5.64 0

MY143 6 8 12.76 5.64 0

MY150 7 6 12.76 5.64 0

MY152 8 1 12.76 5.64 0

MY164 9 0 12.76 5.64 0

MY166 10 5 12.76 5.64 0

MY172 11 14 12.76 5.64 0

MY267 22 4 12.76 5.64 0

MY278 23 14 12.76 5.64 0

MY281 24 4 12.76 5.64 0

MY288 25 5 12.76 5.64 0

64.525

141

g

cc

76.1264.5364.5 UCL

048.1

64.5364.5

LCL


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c Chartc-Chart

0

5

10

15

20

25

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

Subgroup Number

CountofNoncon

formities

c

UCL

c-bar

LCL


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uChart

CL

UCL

LCL


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uChart

ID Number Subgroup n c u UCL u-Bar LCL

30-Jan 1 110 120 1.091 1.51 1.20 0.89

31-Jan 2 82 94 1.146 1.56 1.20 0.84

1-Feb 3 96 89 0.927 1.54 1.20 0.87

2-Feb 4 115 162 1.409 1.51 1.20 0.89

3-Feb 5 108 150 1.389 1.52 1.20 0.88

4-Feb 6 56 82 1.464 1.64 1.20 0.76

28-Feb 26 101 105 1.040 1.53 1.20 0.87

1-Mar 27 122 143 1.172 1.50 1.20 0.90

2-Mar 28 105 132 1.257 1.52 1.20 0.88

3-Mar 29 98 100 1.020 1.53 1.20 0.87

4-Mar 30 48 60 1.250 1.67 1.20 0.73

20.12823

3389

n

cu

09.1110

120

30

n

cuJan

51.1110

20.1320.1

30

JanUCL

89.0110

20.1

320.130

JanLCL


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qc chapter 4

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