Welcome to Problem Solving Through 7 QC TOOLS

1
Welcome toProblem Solving Through7 QC TOOLS
2
7 QC Tools

• Pareto Diagram
• Cause Effect Diagram
• Graphs
• Check Sheet / Check List
• Scatter Diagram
• Histograms
• Control Charts

TOOLS
3
The term 7 tools for QC is named after the 7
tools of the famous warrior, Benkei. Benkei owned
7 weapons, which he used to win all his battles.
Similarly, from my own experience, you will find
that you will be able to solve 95 of the
problems around you if you wisely use the 7 tools
of QC. - ISHIKAWA KAORU, Professor Emeritus,
University of Tokyo
4
COURSE OBJECTIVE

• Impart a practical understanding in using
  Seven QC Tools
• Enable participants to deploy efficient and
  effective problem solving methods in BMM

5
COURSE CONTENTS
Chapter 1 Problem Solving Process Chapter 2 7
QC Tools Check Sheets Chapter 3 7 QC Tools
Pareto Chart Chapter 4 7 QC Tools
Histograms Chapter 5 7 QC Tools Cause and
Effects Diagrams Chapter 6 7 QC Tools Scatter
Diagrams Chapter 7 7 QC Tools Graphs Chapter
8 7 QC Tools Control Charts
6
The details Pareto Diagram
The Pareto Diagram is a bar graph with a
cumulative curve connecting the different points.
To draw this diagram, the problems need to be
first categorized according to phenomenon or
causes such as defects and corrections, before
data is collected and arranged in order of the
number of defects or the number of corrections.
This order is then expressed with the bar graph.
7
Cause and Effect Diagram
The cause and effect analysis which was first
developed by Professor Kaoru Ishikawa of the
University of Tokyo in the 1940s, is also known
as the Fishbone Diagram or the Ishikawa
Diagram This tool is a picture of lines and
symbols designed to represent the relationship
between the effects as problems and the causes
influencing them.
8
Graphs
Graphs refer to the results of statistical
analysis of data (numbers) which are shown in
diagrammatic form to communicate information.
There are numerous types of graphs Bar
Graph Belt Graph Line Graph Radar Graph Pie Graph
9
Check Sheet
Check Sheets are sheets that are designed in
advance to collect the necessary data easily and
systematically, which allow the efficient
checking of all items for inspection and
verification.
No. Symptom Causes Countermeasure When Who Status
1 Xx xx xx xx xx Xx
2 Xx Xx Xx Xx Xx Xx
3 xx Xx Xx Xx Xx xx
10
Scatter Diagrams
The scatter diagram is a diagram where the
relationship between two characteristic values
are plotted on a graph paper and analyzed as to
whether a correlation exists between the 2 sets
of data.This analysis of correlation will enable
you to take the necessary steps to control and
improve the required process.
11
Histogram
A histogram is a type of bar graph which displays
a range of data that has been grouped into
certain classes. It is a useful tool to study the
dispersion of data and analyze certain quality
characteristics of the product or service to
which the data in the histogram refers.
12
Control Charts
The control chart is a chart to examine whether
a process is in a stable condition, or to ensure
that the process in maintained in a stable
condition. The chart collects in time series the
movement of data and indicates any abnormality
and normality in the control limit lines. The
objective of control chart is to control the
process through accurate judgment, investigating
the real cause, taking prompt measure by showing
the appropriate indicators.
13
CHAPTER 1 PROBLEM SOLVING PROCESS
14
WHAT IS A PROBLEM ?

• Difficult matter requiring a solution
• Something hard to understand or accomplish
• Whatever stop us doing things better or more
  effective
• An opportunity for improvement

15
DEFINITION OF PROBLEM SOLVING

• A process to analyze problems, to determine and
  eliminate root causes.

16
PROBLEM SOLVING MODEL

• Problem Identification
• Causal Identification
• Causal Analysis
• Solution Implementation
• Standardization
• Status Monitoring

17
POOR PROBLEM SOLVER

• Dont believe that they can solve problems
• Are impatient and give up quickly
• Are careless readers and may begin working
  before they know what the problem is
• Jump to conclusions and expect to go immediately
  from what is given to the answer
• Carelessly organise their work or do not
  organise at all
• Seldom check their work
• Have only one method of working, usually trying
  to recall a formula and quitting if they cant

18
GOOD PROBLEM SOLVER

• Believe they can solve just about any problems
  if they work at it long enough
• Work for long time on a problem before they give
  up
• Read problem carefully, often several times, to
  be certain of what is asked
• Break problems into small steps, solve the steps
  one by one, and look for relationships as they
  work
• Organise their work carefully so they can stop
  at any point and trace their steps
• Check their steps along the way and check their
  final answer
• Use mental models or drawings to visualise the
  problems, and try to remember simpler problems
  that are related

19
PROBLEM SOLVING APPROACH

• Traditional

• Scientific

• Supernatural
• Intuition

20
SCIENTIFIC PROBLEM SOLVING APPROACH

• A disciplined process ( e.g PDCA)
• Extensive data collection
• Utilize suitable statistical tools to perform
  data analysis and monitoring ( e.g 7 QC Tools)
• Conclude facts based on analysed results
• Periodically review results

21
PDCA APPROACH
22
PDCA Vs QC 7 TOOLS
23
CHAPTER 2 CHECKSHEET
24
Description

• Structure form for collecting and analyzing
  data. It can be used to confirm and record that
  steps of a process was done

Purpose

• Check sheets are used to systematically collect
  data. The data collected may be used to plotting
  histograms, pareto charts, etc.
• Can be used as an inspection checksheet, to
  ensure that all related items are checked.

25
TWO BASIC TYPE OF CHECKSHEET

• Data collecting checksheet
• - Process distribution
• - Defective items
• - Defect location
• - Defect cause
• Confirmation checksheet
• - Inspection

26
Data Collecting Checksheet (1)
PROCESS DISTRIBUTION CHECKSHEET

• Used for continuous data e.g weight, length,
  time, energy etc.
• Used when individual data are not of major
  importance.
• Used when need to establish the distribution and
  relationship to the specifications.

27
SAMPLE CHECKSHEET FOR PROCESS DISTRIBUTION
28
PROCESS DISTRIBUTION CHECKSHEET ANALYSIS

• Distribution resemble bell shape, single-peaked,
  symmetrical ?
• Centre of the distribution at nominal value ?
• The spread of the data wider than the
  specification limits ?

29
CONFIRMATION CHECKSHEET

• Used to confirm that the requirements are
  fulfilled.
• Used to enable all necessary items are checked
  without omission.

30
EXAMPLE OF CONFIRMATION CHECKSHEET
31
DISADVANTAGE OF CHECKSHEET

• Cannot reveal any changes overtime.
• Possibility of checks not entered by data
  collector.
• Need to analyse several sheets arranged in
  chronological order to determine the trend.
• Misinterpreting the data due to different
  influencing conditions are present.

32
CHAPTER 3 PARETO CHART
33
DESCRIPTION

• Pareto chart is a bar graph with a cumulative
  curve
• The length of the bars represent frequency of
  occurrence or cost.
• The pareto chart visually shows which are the
  most significant problems, cause or situations.

34
HISTORY

• Vilfredo Pareto, a 19th century economist
  observed that 80 of wealth was owned by only 20
  of the populations.
• 1950 Dr. J.M.Juran discovered that if quality
  problems were arranged in order of frequency of
  occurrence, relatively few causes accounted for
  the bulk of the problems.

35
PARETO CHART APPLICATION

• Identify the major problem or concern for
  improvements.
• Can be applied for improvement in all areas.
• Shows whether the actions taken are effective.

36
CONSTRUCTION OF PARETO CHART
Step 1 Determine the problem to be studied
Step 2 Identify the data to be used,
frequency
cost, etc
Step 3 Identify the categories
Step 4 Decide the period for data collection
( If comparing the results or
different
Pareto chart, the time period
should be
the same)
Step 5 Collect the data and total the
frequency
of occurrences in each category
37
Step 6

• Arrange the categories in descending order,
  calculate the percentage and cumulative
  percentage for each category.
• Example Cause of Machine Breakdown

Frequency Occur Frequency Cumulative
Component failure 20 (20/47) x 100 42.6 42.6
Program Hang 14 29.8 72.4
Elec. Contact 4 8.5 80.9
Elec. Component 3 6.4 87.3
Jammed 3 6.4 93.7
Operation 2 4.2 97.9
Others 1 2.1 100
47 100
38
Step 7

• On a piece of graph, draw the vertical axis and
  horizontal axis.

15
10
5
39
Step 8

• Place the categories in the horizontal axis in
  the descending order, the category having maximum
  count on the left and so on. ( keep all the
  horizontal scale same width for all categories )

40
Cause of Machine Breakdown
20
A - Component failure B - Program Hang C - Elec.
Contact D - Elec. Component E - Jammed F -
Operation G - Others
15
10
5
A
B
C
D
E
F
G
41
Step 9
Draw the right vertical scale for cumulative
percentage, set the maximum value (100) on the
scale corresponding to the left vertical
axis. Plot the cumulative percentage line on the
chart
Step 10
Give title to all the axis and chart
42
Cause of Machine Breakdown
100
CUM.PERCENTAGE
FREQUENCY
50
20
A - Component failure B - Program Hang C - Elec.
Contact D - Elec. Component E - Jammed F -
Operation G - Others
15
10
5
A
B
C
D
E
F
G
A
B
C
D
E
F
G
43
SPECIAL NOTES

• Choose the categories carefully, ensure that the
  categories represent the problem under study.

Eg To study the high defective rate problem,
the categories should be the type of defect.

• Make sure the terms used are consistent between
  data collected and the Pareto chart

• The vertical may represent the followings -

• Number of defects, reworks or complaint from
  customer
• Cost
• Time lost or waiting
• Cases of accident

44
SPECIAL NOTES (CONT.)

• The horizontal axis may represent the followings
  -

• Type of defects
• Cause of defects
• Different materials
• Different locations, people, machine

• The trick study the data before start
  plotting the pareto chart

• Use Pareto chart to compare before and after
  improvement, make sure the data collection
  processes are the same.

45
EXERCISE 3a
46
CHAPTER 4 HISTOGRAM
47
Description

• Histogram is a bar graph that shows the
  distribution of a set of data
• The shape of the histogram will tell the
  consistency of one product or process behavior

48
Application

• To show the variability of a process, product,
  material, vendor, etc
• To show the central tendency ( mode and mean )
  of a set of measurements.
• To illustrate whether product specifications are
  met.
• To understand the characteristics of the
  populations from which the sample are taken.

49
CHARACTERISTICS

• Data are displayed as a series of rectangles of
  equal width and varying heights.
• Width represents and interval within the range
  of data.
• Height represents the number of data values
  within a given interval.
• Pattern of varying heights shows the
  distributions of data values.
• Pattern provide information on the process
  behavior.

50
SAMPLE OF HISTOGRAM
Frequency
Class Interval
51
EXERCISE
Data 1 3, 4, 4, 5, 5, 5, 6, 6, 6, 6, 7, 7, 7,
8, 8, 9
Mean Range
Std Dev
Data 2 3, 5.5, 5.6, 5.7, 5.7, 5.7, 6, 6,6,
6,6.3, 6.3,6.3,6.4, 6.5, 9
Mean Range
Std Dev
52
CHAPTER 5 CAUSE AND EFFECT DIAGRAMS
53
DESCRIPTION

• Tool in allowing a team to identify, explore and
  graphically display, in increasing details, all
  of the possible causes related to a problem or
  condition to discover its root cause(s)

54
HISTORY

• Developed by Dr. Kaoru Ishikawa in 1943
• Also known as fishbone diagrams or Ishikawa
  diagrams

55
APPLICATION

• Enables a team to focus on the content of the
  problem, not on the history of the problem or
  differing personal interests of team members.
• Creates a snapshots of the collective knowledge
  and consensus of a team around a problem. This
  builds support for the resulting solutions.
• Focuses the team on causes, not symptoms.

56
TYPES

• Dispersion Analysis
• Process Classification
• Cause Enumeration

57
TYPE 1 DISPERSION ANALYSIS
This is a three step process
Step 1 Write down the effect to be investigated
and draw the backbone arrow to it. In the
example shown below the effect is Incorrect
deliveries
Causes
Effect
Incorrect deliveries
58
Step 2 Identify all the board areas of enquiry in
which the causes of the effect being investigated
may lie. For incorrect deliveries the diagram may
then become
Communication
Skills
Incorrect deliveries
Transport
Procedures
59
Step 3 This step requires the greatest amount of
work and imagination because it requires you ( or
you and your team) to write in all the detailed
possible causes in each of the board areas of
enquiry. Each cause identified should be fully
explored for further more specific cause which,
in turn, contribute to them.
60
Communication
Skills
Lack of information
procedure
product
documentation
Picking Slips
Telephone Order
Knowledge
Legibility
Picking Slips
ambiguity
literacy
Lack of knowledge
Incorrect deliveries
Incorrect dept
Incorrect person
consistency
carriers
manual
Customer database
Incorrect Address
automated
efficiency
Not up-to-date
methods
correctness
reliability
In correct program
Transport
Procedures
61
TYPE 2 PROCESS CLASSIFICATION
Machine down during test
Weighing
Marketing Plate
Loose Units
In box
Drop units
Lot Labeling
Labeling
Merge Lots
Visual Inspection
Testing and Marketing
Mixing Product
Materials
Packing
Picking up loose units
Waiting conformation units
Stage too close
Change shift
62
TYPE 3 CAUSE ENUMERATION

• All the possible causes are simply listed (
  Brainstorming session )
• Once all the causes are listed, they are placed
  in the major categories in the cause and effect
  diagrams
• The advantage of this type of diagram is that
  all identified causes are listed
• The disadvantage is that it is sometime
  difficult to relate all the causes listed to the
  categories

63
BRAINSTORMING
DESCRIPTION

• A technique for tapping creative thinking during
  the construction of cause and effect diagram
• Maximize the brainpower of a team
• Use to generate ideas/issues
• Use to clarify ideas/issues

64
KEY STEPS IN BRAINSTORMING SESSION

• Identify a facilitator
• Clarify purpose of the session
• Review rules of brainstorming
• Generate ideas taking turns
• Display ideas
• Review ideas for clarification

65
ROLES OF FACILITATOR

• Guide brainstorming session
• Ask questions to excite thinking
• Align when session goes off target

66
TWO PHASES

• Generation

- Only ideas are generated and no clarification
or analysis carried out

• Clarification

- Ideas generated are clarified if necessary for
all to understand and followed by evaluation of
the ideas
67
PHASES 1 IDEAS GENERATION

• Let all members speak freely
• Keep to the rule
• See problem from different angle
• Note all viewpoints

68
BRAINSTORMING RULES

• No criticism
• The more ideas, the better
• The wilder the ideas, the better
• Hitch-hike on other ideas if possible

69
PRECAUTIONS OF
BRAINSTORMING

• A strong but not dominating facilitator
• Keep each session to no more than 2 to 3 hour
  preferably
• Take relieve breaks after major sections

70
NOTE FOR CAUSE AND EFFECT

• Do not confuse cause, effect and countermeasure
• Use the wisdom and knowledge of the team
• Should not be only problem related, use it for
  improvement
• Use as a visual control
• Be innovative when using Cause and effect
  diagrams

71
READING THE CAUSE AND EFFECT DIAGRAMS

• Pursue the causes actively

- the most probable may not be the most obvious

• Ascertain cause before checking countermeasure
• Understand the casual relationship to enable
  work progress
• Badly arrange cause and effect diagram will
  reduce effectiveness

72
USING A CAUSE AND EFFECT DIAGRAMS

• Make use of team knowledge through brainstorming
  sessions
• Successful countermeasure to be mad into
  standards
• Train all to use diagrams
• Continuously use Cause and effect diagram for
  each new problem or opportunity

73
CAUSE AND EFFECT DIAGRAMS GUIDELINES
C523.DOC