Quality control

1. Introduction to Quality and
Quality Tools
Unit 4

2. Seven QC Tools
 Dr. Kaoru Ishikawa was first total quality management guru,
who has been associated with the development and
advocacy of using the seven quality control (QC) tools in the
organizations for problem solving and process
improvements.
 Seven quality control tools are a set of the QC tools that
can be used for improving the performance of the
production processes, from the first step of producing a
product or service to the last stage of production.
 This study found that these tools have the significant roles
to monitor, obtain, analyze data for detecting and solving
the problems of production processes, in order to facilitate
the achievement of performance excellence in the
organizations.

3. Seven basic quality control tools
These seven basic quality control tools, which
introduced by Dr. Ishikawa, are :
1) Check sheets
2) Flow Chart
3) Histograms
4) Pareto charts
5) Cause-and-effect diagrams
6) Scatter diagrams
7) Control charts

4. Cause & Effect Diagram
A graphic tool that helps identify, sort, and display possible
causes of a problem or quality characteristic(also called Ishikawa
or fishbone chart).
• Ishikawa is considered to be the founder and first promoter of
the ‘Fishbone’ diagram (or Cause-and-Effect Diagram) for root
cause analysis and the concept of Quality Control (QC) circles .
• Cause and effect diagram was developed by Dr. Kaoru Ishikawa
in 1943.
• The fishbone diagram identifies many possible causes for an
effect or
problem. It can be used to structure a brainstorming session. It
immediately sorts ideas into useful categories
• It has also two other names that are Ishikawa diagram and
fishbone because the shape of the diagram looks like the
skeleton of a fish to identify quality problems based on their
degree of importance

5. Cause & Effect Diagram
• Benefits:-
• Helps to determine root causes
• Encourages group participation
• Uses an orderly, easy-to-read format
• Increases process knowledge
• Lets take an example of poor gas mileage in a car
and find out the possible causes those
influencing mileage, it include Methods,
Machinery, people, Material effecting mileage.

6. • The cause and effect diagram is a problem-solving tool that
investigates and analizes systematically all the potential or
real causes that result in a single effect.
• This diagram can provide the problem-solving efforts by
“gathering and organizing the possible causes, reaching a
common understanding of the problem, exposing gaps in
existing knowledge, ranking the most probable causes, and
studying each cause”
• The generic categories of the cause and effect diagram are
usually six elements (causes) such as environment,
materials, machine, measurement, man, and method

7. REJECTION

10. Scatter Diagram
• Scatter diagram is a powerful tool to draw the distribution of information in
two dimensions, which helps to detect and analyze a pattern relationships
between two variables (as an independent variable and a dependent
variable),
• and understanding if there is a relationship between them, so what kind
of the relationship is (Weak or strong and positive or negative).
• The shape of the scatter diagram often shows the degree and direction of
relationship between two variables, and the correlation may reveal the
causes of a problem.
• Scatter diagrams are very useful in regression
• The scatter diagram can indicate that there is which one of the following
correlation between two variables:
• a) Positive correlation;
• b) Negative correlation,
• c) No correlation,

11. Rough
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12. Control Chart
• A quality control chart is a graphic that shows whether
sampled products or processes are meeting their intended
specifications (25+/-.5)
• If not, the chart will show the degree by which they vary
from specifications
• What is a Control Chart Used for?
• Control Charts can be used to:
• Determine whether a process is operating within
acceptable limits
• You can use control charts to spot unusual patterns in the
process
• You can use them to determine whether there is any trend
in the data

13. Control Chart
• Named after Walter A. Shewhart, this quality
improvement tool can help quality assurance
professionals determine whether or not a process is
stable and predictable, making it easy for you to
identify factors that might lead to variations or
defects.
• Control charts use a central line to depict an
average or mean, as well as an upper and lower
line to depict upper and lower control limits based
on historical data.
• By comparing historical data to data collected
from your current process, you can determine
whether your current process is controlled or
affected by specific variations.
• Using a control chart can save your organization time
and money by predicting process performance,
particularly in terms of what your customer or
organization expects in your final product.

16. Check sheets
• Check sheets are simple forms with certain formats that can help the
user to record data in an firm systematically.
• Data are “collected and tabulated” on the check sheet to record the
frequency of specific events during a data collection period.
• Check sheets can be used to collect quantitative or qualitative
data. When used to collect quantitative data, they can be called a
tally sheet.
• A check sheet collects data in the form of check or tally marks
that indicate how many times a particular value has occurred,
allowing you to quickly zero in on defects or errors within your
process or product, defect patterns, and even causes of specific
defects.
• With its simple setup and easy-to-read graphics, check sheets
make it easy to record preliminary frequency distribution data
when measuring out processes. This particular graphic can be used
as a preliminary data collection tool when creating histograms, bar
graphs, and other quality tools.

18. Flowchart
• Flowchart presents a diagrammatic picture that
indicates a series of symbols to describe the sequence
of steps exist in an operation or process.
• On the other hand, a flowchart visualize a picture
including the inputs, activities, decision points, and
outputs for using and understanding easily
concerning the overall objective through process.
• This chart as a problem solving tool can apply
methodically to detect and analyze the areas or points
of process may have had potential problems by
“documenting” and explaining an operation, so it is
very useful to find and improve quality into process.

19. FLOWCHART
• A Diagram that uses graphic symbols to show the
nature and flow of the steps in a process.
Benefits
• Better understanding of process
• Identify problem areas and improvement
• Provide tool for training

20. Flow Chart

21. Pareto Chart
• Pareto chart helps to Narrow problem area or
prioritize the significant problems for corrective
measures.
• Pareto Chart based on Pareto 80-20 rule.
• It means that 80 percent of the problems/failures
are caused by 20 percent of the few major
causes/factors which are often referred as Vital Few.
• And the remaining 20 percent of the problems are
caused by 80 percent of many minor causes which
are referred as Trivial Many.
• Hence, it gives us information about Vital few from
Trivial many.

22. “Pareto Chart”
• “Pareto Chart” also called as “Pareto Diagram“.
• Named after Italian Economist Wilfredo Pareto.
• 80 % of issues comes from 20% of the problems.
• Shows focus area to get most gains.
• Bar chart arranged in descending order of height.
• Bars on left side relatively important than those in right.
• Separates “Vital few” from “Trivial many”.
• As a quality control tool, the Pareto chart operates according to the 80-20 rule.
• This rule assumes that in any process, 80% of a process’s or system’s problems are caused by 20% of
major factors, often referred to as the “vital few.” The remaining 20% of problems are caused by 80% of
minor factors.
• A combination of a bar and line graph, the Pareto chart depicts individual values in descending order
using bars, while the cumulative total is represented by the line.
• The goal of the Pareto chart is to highlight the relative importance of a variety of parameters, allowing you
to identify and focus your efforts on the factors with the biggest impact on a specific part of a
process or system.
•

23. How to make a “Pareto Chart” ?
• Step 1: Record the data – Refer Check Sheet.
• Step 2: Order the data.
• Step 3: Label the vertical axis.
• Step 4: Label the Horizontal axis.
• Step 5: Plot the Bars.
• Step 6: Add up the counts.
• Step 7: Add a cumulative line.
• Step 8: Add title and Legends.
• Step 9: Analyze the Chart.
• Step 10: Interpret the results.

26. Histogram
• The histogram represents frequency distribution
of data clearly and concisely amongst different
groups of a sample, allowing you to quickly and
easily identify areas of improvement within your
processes.
• With a structure similar to a bar graph, each bar
within a histogram represents a group, while
the height of the bar represents the frequency
of data within that group.
• Histograms are particularly helpful when breaking
down the frequency of your data into
categories such as age, days of the week,
physical measurements etc

27. Histogram
• The histogram can help you represent frequency
distribution of data clearly and concisely amongst
different groups of a sample, allowing you to
quickly and easily identify areas of improvement
within your processes.
• Histograms are particularly helpful when breaking
down the frequency of your data into categories
such as age, days of the week, physical
measurements, or any other category that can be
listed in chronological or numerical order.

28. Histogram

29. Quality Circle
• A quality circle is a participatory management technique that enlists the
help of employees in solving problems related to their own jobs.
• Circles are formed of employees working together in an operation who
meet at intervals to discuss problems of quality and to devise solutions for
improvements.
• Quality circles have an autonomous character, are usually small, and are
led by a supervisor or a senior worker.
• Employees who participate in quality circles usually receive training in
formal problem-solving methods—such as brain-storming, pareto analysis,
and cause-and-effect diagrams—and are then encouraged to apply these
methods either to specific or general company problems.
• After completing an analysis, they often present their findings to
management and then handle implementation of approved solutions.
Pareto analysis, by the way, is named after the Italian economist, Vilfredo
Pareto, who observed that 20 percent of Italians received 80 percent of
the income—thus the principle that most results are determined by a few
causes.

30. Quality Circle
• Quality circles were originally associated with Japanese
management and manufacturing techniques. The introduction of
quality circles in Japan in the postwar years was inspired by the
lectures of W. Edwards Deming (1900—1993), a statistician for the
U.S. government. Deming based his proposals on the experience of
U.S. firms operating under wartime industrial standards.
• Noting that American management had typically given line
managers and engineers about 85 percent of the responsibility for
quality control and line workers only about 15 percent, Deming
argued that these shares should be reversed.
• He suggested redesigning production processes to account more
fully for quality control, and continuously educating all employees
in a firm—from the top down—in quality control techniques and
statistical control technologies. Quality circles were the means by
which this continuous education was to take place for production
workers.

34. Quality Circle
• Toyota liked the quality circle idea and started this
concept throughout their production system and
other areas of the manufacturing process.
• Companies around the world realize the importance
of this concept and began implementing this
strategy.
• The quality circle concept got more popular in the
1960s, 1970s, 1980s and now being used worldwide
in the industries along with TQM and Lean
Manufacturing best practices to improve quality and
productivity.

35. Management
Director Sir

36. Class Teacher
HOD Sir
Students

37. Quality Circle Steps
1. Defining the Problem
2. Analyzing the Problem
3. Identifying the Cause
4. Finding out the Root Cause
5. Data Analysis on Root Cause
6. Developing Solution
7. Foreseeing Possible Resistance
8. Trail, Implement and Checking Performance
9. Regular Implementation
10. Follow – up / Review

39. Brainstorming
• Brainstorming is a method of generating ideas
and sharing knowledge to solve a particular
commercial or technical problem, in which
participants are encouraged to think without
interruption.
• Brainstorming is a group activity where each
participant shares their ideas as soon as they
come to mind. At the conclusion of the session,
ideas are categorized and ranked for follow-on
action.