60993779 7 basic tools of quality1

8/2/2019 60993779 7 Basic Tools of Quality1

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Slides Prepared by

Dale Garlen


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Quick Overview

The Seven Tools Histograms, Pareto Charts, Cause and Effect Diagrams,

Run Charts, Scatter Diagrams, Flow Charts, ControlCharts


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Ishikawas Basic Tools of Quality

Kaoru Ishikawa developed seven basic visual toolsof quality so that the average person could analyze

and interpret data.

These tools have been used worldwide bycompanies, managers of all levels and employees.


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HistogramsSlide 1 of 3

Histogram Defined

A histogram is a bar graph that shows frequency data.

Histograms provide the easiest way to evaluate thedistribution of data.


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Creating a Histogram Collect data and sort it into categories.

Then label the data as the independent set or thedependent set. The characteristic you grouped the data by would be the

independent variable.

The frequency of that set would be the dependent variable.

Each mark on either axis should be in equalincrements.

For each category, find the related frequency and makethe horizontal marks to show that frequency.


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Examples of How Histograms Can Be Used

Histograms can be used to determine distribution ofsales.

Say for instance a company wanted to measure therevenues of other companies and wanted to comparenumbers.


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Pareto ChartsSlide 1 of 4

Pareto Chart Defined

Pareto charts are used to identify and prioritizeproblems to be solved.

They are actually histograms aided by the 80/20 ruleadapted by Joseph Juran.

Remember the 80/20 rule states that approximately 80% ofthe problems are created by approximately 20% of the causes.


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Constructing a Pareto Chart First, information must be selected based on types

or classifications of defects that occur as a result of aprocess.

The data must be collected and classified intocategories.

Then a histogram or frequency chart is constructed

showing the number of occurrences.


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An Example of How a Pareto Chart Can Be Used Pareto Charts are used when products are suffering from different

defects but the defects are occurring at a different frequency, or only

a few account for most of the defects present, or different defectsincur different costs. What we see from that is a product line mayexperience a range of defects. The manufacturer could concentrateon reducing the defects which make up a bigger percentage of allthe defects or focus on eliminating the defect that causes monetaryloss.

Actual chart is on the next slide Example and chart were obtained from:


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Cause and Effect DiagramsSlide 1 of 4

Cause and Effect Diagram Defined The cause and effect diagram is also called the Ishikawa diagram or

the fishbone diagram.

It is a tool for discovering all the possible causes for a particulareffect.

The major purpose of this diagram is to act as a first step in problemsolving by creating a list of possible causes.


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Constructing a Cause and Effect Diagram First, clearly identify and define the problem or effect for which the

causes must be identified. Place the problem or effect at the right

or the head of the diagram. Identify all the broad areas of the problem.

Write in all the detailed possible causes in each of the broad areas.

Each cause identified should be looked upon for further morespecific causes.

View the diagram and evaluate the main causes. Set goals and take action on the main causes.


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Diagram of the Incorrect Deliveries Example:


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Scatter DiagramsSlide 1 of 4

Scatter Diagrams Defined

Scatter Diagrams are used to study and identify thepossible relationship between the changes observed intwo different sets of variables.


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Constructing a Scatter Diagram First, collect two pieces of data and create a

summary table of the data.

Draw a diagram labeling the horizontal and verticalaxes. It is common that the cause variable be labeled on the X axis

and the effect variable be labeled on the Y axis.

Plot the data pairs on the diagram. Interpret the scatter diagram for direction and

strength.


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An Example of When a Scatter Diagram Can Be Used

A scatter diagram can be used to identify therelationship between the production speed of anoperation and the number of defective parts made.


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An Example of When a Scatter Diagram Can BeUsed (cont.) Displaying the direction of the relationship will

determine whether increasing the assembly line speedwill increase or decrease the number of defective partsmade. Also, the strength of the relationship betweenthe assembly line speed and the number of defectiveparts produced is determined.

Example obtained from:


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Flow ChartsSlide 1 of 3

Flow Charts Defined

A flow chart is a pictorial representation showing all ofthe steps of a process.


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Creating a Flow Chart

First, familiarize the participants with the f low chartsymbols.

Draw the process flow chart and fill it out in detail abouteach element.

Analyze the flow chart. Determine which steps addvalue and which dont in the process of simplifying thework.


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Examples of When to Use a Flow Chart

Two separate stages of a process flow chart should beconsidered:

The making of the product

The finished product


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Run ChartsSlide 1 of 3

Run Charts Defined

Run charts are used to analyze processes according totime or order.


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Creating a Run Chart Gathering Data

Some type of process or operation must be available to take

measurements for analysis. Organizing Data

Data must be divided into two sets of values X and Y. X valuesrepresent time and values of Y represent the measurements takenfrom the manufacturing process or operation.

Charting Data Plot the Y values versus the X values.

Interpreting Data Interpret the data and draw any conclusions that will be beneficial to

the process or operation.


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An Example of Using a Run Chart

An organizations desire is to have their product arrive totheir customers on time, but they have noticed that itdoesnt take the same amount of time each day of the

week. They decided to monitor the amount of time ittakes to deliver their product over the next few weeks.


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Control ChartsSlide 1 of 3

Control Charts Defined

Control charts are used to determine whether a processwill produce a product or service with consistent

measurable properties.


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Steps Used in Developing Process Control Charts Identify critical operations in the process where

inspection might be needed.

Identify critical product characteristics. Determine whether the critical product characteristic is

a variable or an attribute.

Select the appropriate process control chart.

Establish the control limits and use the chart to monitorand improve.

Update the limits.


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An Example of When to Use a Control Chart

Counting the number of defective products or services

Do you count the number of defects in a given product orservice?

Is the number of units checked or tested constant?


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Activity

Process Flow Chart for Finding the Best WayHome Construct a process flow chart by making the best

decisions in finding the best route home. Refer to the prior notes on flowcharts.

Remember: Define and analyze the process, build a step-bystep picture of the process, and define areas of improvementin the process.

Answer is on the next slide

Example obtained from:


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SummaryThis presentation provided learning material foreach of Ishikawas seven basic tools of quality.

Each tool was clearly defined with definitions, a

step-by-step process and an example of how thetool can be used.

As seen through the presentation, these tools arerather simple and effective.


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Works - Sited

Histograms and Bar Graphs.

Your MBA: The Business Study Reference Site.http://yourmba.co.uk/pareto_diagram.htm

Hci Home Services. Cause and Effect Diagram.http://hci.com.au/hcisite/toolkit/causeand.htm

Scatter Diagram. http://sytsma.com/tqmtools/Scat.html

Flowchart.

Run Charts/Time Plot/ Trend Chart.

Foster Thomas S. Managing Quality An Integrative Approach. New Jersey:

Prentice Hall, 2001
http://yourmba.co.uk/pareto_diagram.htmhttp://hci.com.au/hcisite/toolkit/causeand.htmhttp://sytsma.com/tqmtools/Scat.htmlhttp://sytsma.com/tqmtools/Scat.htmlhttp://hci.com.au/hcisite/toolkit/causeand.htmhttp://yourmba.co.uk/pareto_diagram.htm

60993779 7 basic tools of quality1

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