7

QC tools

Property of ACT ( ACMA Centre for
Technology ) 2007

PDF created with pdfFactory Pro trial version www.pdffactory.com

Slide No.

1


Seven QC Tools
Scatter Diagram
Stratification
Histogram
Graph and Control Chart
Cause and Effect Diagram
Pareto Diagram
Check Sheet

Property of ACT ( ACMA Centre for
Technology ) 2007

PDF created with pdfFactory Pro trial version www.pdffactory.com

Slide No.

2

Sl.No

Tools

Function

1

Check Sheet /
Data Sheet

To Collect the data in a simple manner and to
prevent omitting the checks

2

Pareto Daigram

To pick up the important few problems from
the trivial many.

3

Cause and Effect To reorganise the factors (causes) which are
Diagram
influencing the problem

4


Presentation of data in a pictorial form for
Graph and Control
better understanding and see if the process
Chart
is under stable conditions.

5

Histogram

To see the distribution pattern compared
against the standard values.

6

Stratification

To segregate data according to contributing
sources.(Suppliers,machines,operators etc)

7

Scatter Diagram

To see relation between two sets of data
Property of ACT ( ACMA Centre for
Technology ) 2007

PDF created with pdfFactory Pro trial version www.pdffactory.com


Slide No.

3


Check Sheet
Solder Bath Temperature
Checked by :

Raised by :

Take reading of temperature nearest to degree.
Time Temp (0C) Time Temp (0C)
0800
60
1300
61
0900
62
1400
58
1000
59
1500
63
1100
58
1600
63

1200
59
1700
59
Note : Power failure from 12.00 to 12.15 Hours

Property of ACT ( ACMA Centre for
Technology ) 2007

PDF created with pdfFactory Pro trial version www.pdffactory.com

Slide No.

4


What is Check Sheet ?
A Check sheet is a paper form on which item to be
checked have been printed already so that data can be
collected easily and concisely. Its main purposes are
two-fold :
1) To make data-gathering easy ;
2) To arrange data automatically so that they can be
used easily later on

Two Types of Data :
1. Measurement data or Variable data.
2. Attribute data.
Property of ACT ( ACMA Centre for
Technology ) 2007


PDF created with pdfFactory Pro trial version www.pdffactory.com

Slide No.

5


Check sheets are of following types :
a) Check sheet for production process distribution.
b) Defective item check sheet.
c) Defect location check sheet.
d) Defect cause check sheet.

Property of ACT ( ACMA Centre for
Technology ) 2007

PDF created with pdfFactory Pro trial version www.pdffactory.com

Slide No.

6


Check Sheet for Production Process Distribution:
Checks

Deviation
5


Specification

8.300

Specification

10

Frequency
15

20

-10
-9
-8
-7
-6
-5
-4
-3
-2
-1
0
1
2
3
4
5
6

7
8
9
10

1
2
4
6
9
11
8
7
3
2
1
1

Total
Property of ACT ( ACMA Centre for
Technology ) 2007

PDF created with pdfFactory Pro trial version www.pdffactory.com

Slide No.

7

55



Defective Item Check Sheet:
Product :

Date :

Manufacturing stage: Final inspection
Type of defect: Scar,incomplete

Section :
Inspector’s name :

crack,misshapen.

Lot no :

Total no.inspected : 1525

Order no :

Remarks : All items inspected.
Type

Checks

Subtotal

Surface scars

IIII


IIII

IIII

Cracks

IIII

IIII

I

Incomplete

IIII

IIII

IIII

Mishappen

III

3

Others

IIII


5

II

17
11

IIII

IIII

I

26

Total :
Total rejects

62
42

Property of ACT ( ACMA Centre for
Technology ) 2007

PDF created with pdfFactory Pro trial version www.pdffactory.com

Slide No.

8



Defect Location Check Sheet
A
1

2

3

A

1

B

12

15

C

10

11

D

B


C

D

4

1
2

3

1

From the location matrix it is

4

clear that most of the blow holes
are occupied in the segment B2,B3,C2 & C3.

Defect Location Matrix For Blowholes (50 Defective Components)
Property of ACT ( ACMA Centre for
Technology ) 2007

PDF created with pdfFactory Pro trial version www.pdffactory.com

Slide No.

9



Defect Cause Check Sheet.
Mon

Tue

W ed

Thu

Fri

Sat

Equipment Operator
AM

1

PM

oo ox
x

AM

PM

xx


ooo

AM

PM

ooo
xxx

xx

AM

PM

AM

PM

AM

oo xxxx oo
oo

xx

A

oo


2

1

xxx

oo

xx

B
2

xx

o Damage

oo
x Blowhole

Poor finish

Property of ACT ( ACMA Centre for
Technology ) 2007

PDF created with pdfFactory Pro trial version www.pdffactory.com

Crack

Slide No.


Others
10

PM


Points to remembered while making check sheets
v Easy to use and understand.
v Information should be true and accurate.
v Decide objective by involving all the members.
v Use 5W and 1H principle.
v Who will collect the data ?
v When will the data be collected ?
v Where will the data be collected ?
v How will data be collected ?
v Check sheets should be displayed on visible area.
Property of ACT ( ACMA Centre for
Technology ) 2007

PDF created with pdfFactory Pro trial version www.pdffactory.com

Slide No.

11


Benefits of Check Sheets
Data Collection have the following benefits :


• Right decision can be made.
• Errors due to subjective feeling or personal bias are avoided.
• Agreement on decisions necessary rather than different or
subjective opinion.

• Measurement understandable to all.
• Assessments of magnitude of improvements.
• Discovery of causes affecting quality and productivity.
Property of ACT ( ACMA Centre for
Technology ) 2007

PDF created with pdfFactory Pro trial version www.pdffactory.com

Slide No.

12


250

100
85.28

200

91.53

96.75

100


80

156

150

60
105

100

50.98

40

50

20
20

16

9

0

% Cumulative

No of Components


Pareto Diagram

0
Cold
shut

oil shot Damage Chip off Bad app

Types of Defects

Property of ACT ( ACMA Centre for
Technology ) 2007

PDF created with pdfFactory Pro trial version www.pdffactory.com

Slide No.

13


What is Pareto Diagram ?
Pareto diagrams are presentation technique used to
show facts and they help us to separate the “vital few”.
Pareto diagram was first thought out by an Italian economist,
Pareto (1848 - 1923), when he used it as a method for national
income analysis to show that a large proportion of the wealth
was centered around a small minority of people.
After that, an American Quality Control Authority, Mr.Juran used
it in the field of Quality Control.

Property of ACT ( ACMA Centre for
Technology ) 2007

PDF created with pdfFactory Pro trial version www.pdffactory.com

Slide No.

14


Steps to make the pareto diagrams :
1) Decide what problems are to be investigated and how to collect the
data.
2)

Design a data tally sheet listing the items,with space to record their
totals.

3)

Fill out the tally sheet and calculate the totals (Example-1)

4)

Make the pareto diagram data sheet listing the items, their individual
totals,cumulative totals,percentages of overall total, and cumulative
percentages (Example-2)

Property of ACT ( ACMA Centre for
Technology ) 2007


PDF created with pdfFactory Pro trial version www.pdffactory.com

Slide No.

15


Steps to make the pareto diagrams (contd.) :
1)

Draw two vertical axes and a horizontal axis.

2)

Construct a bar diagram.

3)

Draw the cumulative curve (Pareto curve).

4)

Write any necessary items on the diagram.
a) Items concerning the diagram.
b) Items concerning the data.

5) Arrange the items in the order of quantity,and fill out the data sheet.

Property of ACT ( ACMA Centre for

Technology ) 2007

PDF created with pdfFactory Pro trial version www.pdffactory.com

Slide No.

16


Data Tally Sheet - Example -1
Type of Defect

Tally

Crack

IIII

IIII

Scratch

IIII

IIII

Stain

IIII


I

Strain

IIII

IIII

Gap

IIII

Pinhole

IIII

IIII

IIII

Others

IIII

IIII

IIII

Total
10


IIII

IIII

………….

IIII

II

42
6

IIII

IIII

……………………….

IIII

IIII

104
4

IIII

20

14

Total

200

Property of ACT ( ACMA Centre for
Technology ) 2007

PDF created with pdfFactory Pro trial version www.pdffactory.com

Slide No.

17


Data Sheet for Pareto Diagram - Example - 2
Type of
Defect

Number of
Defect

Cumulative
Total

Percentage of
Overall Total

Cumulative

Percentage

Strain

104

104

52

52

Scratch

42

146

21

73

Pinhole

20

166

10


83

Crack

10

176

5

88

Stain

6

182

3

91

Gap

4

186

2


93

Others

14

200

7

100

Total

200

-

100

-

Property of ACT ( ACMA Centre for
Technology ) 2007

PDF created with pdfFactory Pro trial version www.pdffactory.com

Slide No.

18



Parteo Diagram by Defective Items:

No of Defective Units

180

83

160

88

91

100

93

90
80

73

140
120

70


52

60

100
80

50

104

60

40
30

42

40

20

20

20

10

6


4

14

0

10

Cumulative Percentage

April 1 - June 30

200

100

0
D

B

F

A

C

E

Others


A :Crack, B: Scratch, C: Stain, D: Strain, E: Gap, F: Pinhole.
(Number of Units Investigated : 5,000)
Property of ACT ( ACMA Centre for
Technology ) 2007

PDF created with pdfFactory Pro trial version www.pdffactory.com

Slide No.

19


Cause and Effect Diagram
Man

Machine

Characteristics

Material

Method

Property of ACT ( ACMA Centre for
Technology ) 2007

PDF created with pdfFactory Pro trial version www.pdffactory.com

Slide No.


20


What is Cause and Effect Diagram ?
Any defect in a component, a product or service could be
due to one or more causes.To find out the relationship between
the causes and effect, a diagram is drawn systematically by
mapping out all the probable causes influencing the effect.
This is called a “Cause and Effect Diagram”
Cause and effect diagram was introduced by “Dr.K.Ishikawa”.
He used it in Kawasaki Iron Works in 1943.
Since final diagram looks like a fish bone it is also called as
Fish Bone Diagram.
Property of ACT ( ACMA Centre for
Technology ) 2007

PDF created with pdfFactory Pro trial version www.pdffactory.com

Slide No.

21


Format of a Cause and Effect Diagram
Main Cause

Main Cause
A
Level 3

Cause

Level 2
Cause
Level 1
Cause
Characteristics

Main Cause

Main Cause

Above diagram depicts the basic format of Cause and Effect diagram.
There is a hierarchical relationship of the effect to the main causes and
their subsequent relationship to the sub-causes.
Property of ACT ( ACMA Centre for
Technology ) 2007

PDF created with pdfFactory Pro trial version www.pdffactory.com

Slide No.

22


Procedure for Making Cause-and-effect Diagrams
for Identifying Causes:
1) Determine the quality characteristics.
2)


Choose one quality characteristics and write it on the righthand side of a sheet of paper, draw in the backbone form
left to right, and enclose the characteristic in a square. Next,
write the primary causes which affect the quality characteristics
as big bones also enclosed by squares.
Property of ACT ( ACMA Centre for
Technology ) 2007

PDF created with pdfFactory Pro trial version www.pdffactory.com

Slide No.

23


Procedure for Making Cause-and-effect Diagrams
for Identifying Causes – (contd):
3) Write the causes (Secondary causes) which affect the big
bones (primary causes) as medium-sized bones and write the
causes (tertiary causes) which affect the medium-sized bones
as small bones.
4)

Assign an importance to each factor and mark the particularly
important factor that seem to have a significant effect on the
quality characteristics.

5)

Record any necessary information.
Property of ACT ( ACMA Centre for

Technology ) 2007

PDF created with pdfFactory Pro trial version www.pdffactory.com

Slide No.

24


Example of Cause-and-Effect Diagram :
Health

Spirit

Relaxation

Encouragement
Pride
Fighting spirit

Rest

Nutrition Calories

Amusement

Meal

Time
Sleep


Patience

Devotion
Calmness

Carefulness

Composure

Quantity

Concentration
Confidence

Depth
Theory
Planning
Rules
Common
sense

Observation

Strategy

Power

Information
Study of

opponent
Analysis

Defeat in a
sports match

Motion
Speed
Cooperation

Teamwork
Judgement of situation Function

Experience of matches

Exercise
Quality
Quantity
Advice
Form

Model

Technique

Property of ACT ( ACMA Centre for
Technology ) 2007

PDF created with pdfFactory Pro trial version www.pdffactory.com


Schedule

Repetition
Slide No.

25