Topic 2 Topic 2

Quality SpecificationQuality Specification

LecturesLectures

Mr. Mohd Syafarim B. Md IshakMr. Mohd Syafarim B. Md Ishak

IntroductionIntroduction

1. `Comprehensive details of product attributes’ e.g.: grade, weight, nutritional values, microbe

count, etc 2. Quality specifications is needed in any

condition e.g.: raw materials, process, finished goods,

storage, handling Documented: simple, precise, legible 

ObjectiveObjective

1. To ensure wholesome, hygienic, sincerely packed and labeled product.

2. ‘Wholesome’: good in ecstatic value (taste), nutritious and safe to consume

Ishikawa’s Basic Tools of QualityIshikawa’s Basic Tools of Quality

Kaoru Ishikawa developed seven basic visual tools of quality so that the average person could analyze and interpret data.

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

Seven Quality ToolsSeven Quality Tools

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

Diagrams, Run Charts, Scatter Diagrams, Flow Charts, Control Charts

HistogramsHistograms

Histogram DefinedA histogram is a bar graph that shows

frequency data.Histograms provide the easiest way to evaluate

the distribution of data.Provide a quick representation of the “spread”

and “centering” of a process.

Histograms cont…..Histograms cont…..

1. Steps to build a Histogram• Collect data for analysis.

• At least 50 to 100 data points• Use historical data to find patterns or to use as a baseline for past performance

• Determine the range of the data set.• Smallest value subtracted from largest value

• Determine quantity of categories.• Take the square root of total number of data points and round to nearest whole number

Step to a build Histograms Step to a build Histograms cont…..cont…..

• Determine each category’s data point.

• Mid-point of each category

• Plot data on a vertical bar-graph.

• Frequency on Y-axis

• Categories on X-axis

• For each class interval, draw bar with the

height equal to frequency count

Advantage of a HistogramsAdvantage of a Histograms

• Display large amounts of data that are difficult to interpret in a tabular form

• Show the relative frequency of occurrences of the various data values

• Reveal the variation, centering, and distribution shape of the data

• Very useful when calculating capability of a process

• Helps predict future performance of a process

Example of a HistogramExample of a HistogramCategory

Class boundary

Mid-point Frequency

1 10.00 - 10.19 10.1 12 10.20 - 10.39 10.3 63 10.40 - 10.59 10.5 124 10.60 - 10.79 10.7 85 10.80 - 10.99 10.9 66 11.00- 11.19 11.1 3

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10.00 -10.19

10.20 -10.39

10.40 -10.59

10.60 -10.79

10.80 -10.99

11.00-11.19

Pareto ChartsPareto Charts

Pareto Chart DefinedPareto charts are used to identify and prioritize

problems to be solved.They are actually histograms aided by the

80/20 rule adapted by Joseph Juran.Remember the 80/20 rule states that

approximately 80% of the problems are created by approximately 20% of the causes.

Advantages of a Pareto ChartsAdvantages of a Pareto Charts

• Focuses efforts on problems with greatest

potential for improvement

• Distinguishes the critical causes from the less

significant causes

• Helps prevent “shifting the problem” where the

solution removes some causes but worsens

others

Advantages of a Pareto ChartsAdvantages of a Pareto Charts

• Measure the impact of improvement projects when comparing charts “before” and “after”

• The chart shows the relative importance of problems in a simple, quickly interpreted, visual format.

• Progress is measured in a highly visible format that provides incentive to push on for more improvement.

Step to a build Pareto chartStep to a build Pareto chart

• Identify problem

• Choose categories that will be monitored

• Choose the most meaningful unit of

measurement

• Frequency

• Cost

• Determine time period

• Long enough to represent situation

• Scheduled time to collect data is typical of a

workday

Step to a build Pareto chart cont….Step to a build Pareto chart cont….

• Collect data

• Compare the frequency of each category

• Draw chart:

• List the categories on the horizontal line

• Descending order, from left to right

• Frequencies on the vertical line

Step to a build Pareto chart cont….Step to a build Pareto chart cont….

• Draw the cumulative percentage line showing

categories contribution

• Optional

• Draw vertical line on the right side of the

chart

• Plot cumulative values from left to right

• Interpret results

• Tallest bar represents biggest contributor

• Perform analysis of category that has the

“most

impact”

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35%

61%

79%

91%

97%100 %

50 %

Frequency

Cum %Example of a Pareto ChartExample of a Pareto Chart

Further Analysis Using Pareto Further Analysis Using Pareto ChartsCharts• Major cause breakdown:

• Tallest bar is broken down into sub-causes

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Missing address Driver mistake Latedocumentation

Transportationproblems

Administrativedelays

Late delivery

•Before and after:• New Pareto bars are drawn side-by-side with the original Pareto showing effect of change

Further Analysis Using Pareto Further Analysis Using Pareto ChartsCharts

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Before After

Further Analysis Using Pareto Further Analysis Using Pareto ChartsCharts•Change measurement scale:

• Same categories are used but measured differently. Typically cost and frequency.• This exercise defines the category of “most impact”.

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$2,500

$1,850

$1,200$800

$220 $200$0

$500

$1,000

$1,500

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$2,500

$3,000

Wrong product Not received Missing parts Wrongaddress

Damagedcontainer

Late delivery

Cost/month

1. Flow Charts DefinedA flow chart is a pictorial representation

showing all of the steps of a process.

2. Flow charts are used to identify the actual path

of a product or service.

3. Flow charts show:

• Sequential work activities

• Inputs for each action

• Outputs from each activity

Process Flow ChartProcess Flow Chart

Provide common understanding of how a process works.

Identifies problem areas, unexpected complexity, redundancies, and areas of potential improvement

Serves as a training aid

Provides basis for documentation. Identifies location where additional data can be collected and investigated

Advantages of a Flow ChartAdvantages of a Flow Chart

Shows an activity performed in the process

Shows a point in the process where a Yes/No

question is being asked or a decision is required

Identifies a break in the flow chart and is continued elsewhere on the same

page or another page

Shows the flow of the process

Shows the beginning and end process

Symbols of a Flow ChartSymbols of a Flow Chart

A

List the basic steps of the process.

Determine the logical sequence of the steps.

Identify the inputs of each step.

Determine the outputs of each step.

Draw the chart using the symbols to show the

actions and decisions.

Steps to Build a Flow ChartSteps to Build a Flow Chart

Example of a Flow ChartExample of a Flow Chart

Team is given task to write procedure

Develop outline

Completedraft

Review draft

Revise Draft with changes

CompleteFinal

version

Send toRelease

Dept.

Draftapproved

Releaseprocedure

yes

No

Run Charts DefinedRun charts are used to analyze processes

according to time or order.

Run ChartRun Chart

Creating a Run ChartGathering Data

Some type of process or operation must be available to take measurements for analysis.

Organizing DataData must be divided into two sets of values X

and Y. X values represent time and values of Y represent the measurements taken from the manufacturing process or operation.

Charting DataPlot the Y values versus the X values.

Interpreting DataInterpret the data and draw any conclusions that

will be beneficial to the process or operation.

Creating a Run ChartCreating a Run Chart

An Example of Using a Run ChartAn organization’s desire is to have their

product arrive to their customers on time, but they have noticed that it doesn’t take the same amount of time each day of the week. They decided to monitor the amount of time it takes to deliver their product over the next few weeks.

Example of a Run ChartExample of a Run Chart

Cause and Effect AnalysisCause and Effect Analysis

Cause and Effect Diagram DefinedThe 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 particular effect.The major purpose of this diagram is to act as

a first step in problem solving by creating a list of possible causes.

Advantage of a Cause and Effect Advantage of a Cause and Effect DiagramDiagram

Clearly illustrates the various causes affecting a

process:

• Relationship between these causes

• Where are they occurring

Helps in finding the most basic cause of the

problem

Motivates team members participation

Steps to Build a Cause and Effect Steps to Build a Cause and Effect DiagramDiagramPlace problem statement in a box to the right-hand

side of the paper.Select the major cause or categories and place them

to the left of the problem statement.• 4 M’s (Production process):

• Materials• Manpower• Machinery/equipment• Method

• 4 P’s (Service process):• Policies• Procedures• People• Plant / equipment

Steps to Build a Cause and Effect Steps to Build a Cause and Effect Diagram cont……Diagram cont……

Draw a box around each category and connect

to a line pointing out towards the problem statement.

Using the brainstorming technique, generate ideas

of causes, on the major categories.

Record these ideas on a line off the applicable

major category line.

For each cause listed on the diagram, ask “why

does this happen?”.

For each response, ask the same question.

Each successive answer is another possible cause

Look for causes that repeat across major cause

categories.

Ensure all team members agree on the problem

and causes statements.

Steps to Build a Cause and Effect Steps to Build a Cause and Effect Diagram cont……Diagram cont……

Example of a Cause and Effect Example of a Cause and Effect DiagramDiagram

Late deliveries

Method Material

ManpowerMachinery/equipment

Drivers get lost

Drivers don’tShow upUnreliable trucks

Not enough trucks

Poor dispatching

Poor handling of large orders

Run out of products

Not capacity for peak periods

Wrong address on shipper

Database Input error

Poor planning

Lack of trainingLack of

training

Scatter Diagrams DefinedScatter Diagrams are used to study and

identify the possible relationship between the changes observed in two different sets of variables.

Scatter DiagramScatter Diagram

Provides visual and statistical means to test the

strength of a potential relationship

Provides a good follow-up to the cause and effect

diagram to find out if there is a connection between

the cause and the effect

Advantages of the Scatter DiagramAdvantages of the Scatter Diagram

Steps to Build a Scatter DiagramSteps to Build a Scatter Diagram

Constructing a Scatter DiagramFirst, collect two pieces of data and create a

summary table of the data.Draw a diagram labeling the horizontal and

vertical axes. 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.

Examples of a Scatter DiagramExamples of a Scatter Diagram

An Example of When a Scatter Diagram Can Be UsedA scatter diagram can be used to identify

the relationship between the production speed of an operation and the number of defective parts made.

Variable 1

Var

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le 2

Control ChartsControl Charts

• Control Charts Defined Control charts are used to determine whether a process will produce a product or service with consistent measurable properties. • Line graph of measurements of a process overtime that has statistically based control limits placed on it

• Process control charts monitor and display variations in a process output. • Control limits are based on process variation

• Define expected variation range due to common causes• +/- three standard deviations from centerline

Types of a Control ChartsTypes of a Control Charts•Two primary types are:

• Control charts for variables:• Most used: X –R

• X is average values• R is range

• Others: Run charts, moving range charts (MX –MR charts)

• Control charts for attributes:• p chart: fraction defective• np chart: number of defectives• c chart: number of defects

Steps to Build a Control ChartsSteps to Build a Control ChartsSteps Used in Developing Process

Control ChartsIdentify 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 monitor and improve.Update the limits.

Advantages of a Control ChartsAdvantages of a Control Charts

• Focuses attention on detecting and monitoring process variation over time

• Distinguishes “special” from “common” causes

• Helps predict performance of a process

• Helps improve a process to perform consistently

• Provides a common language to discuss process behavior

Examples of a Control ChartsExamples of a Control Charts

An Example of When to Use a Control ChartCounting the number of defective products

or services Do you count the number of defects in a given

product or service? Is the number of units checked or tested

constant?

Examples of a Control ChartsExamples of a Control Charts

Upper control limit

Lower control limit

Centerline

3 std.deviations

3 std.deviations

Data plot

Point out-of-control(out of the control limits boundaries)

SummarySummary

•The seven tools of quality discussed in this module

are considered to make up the fundamental

continuous improvement toolkit.

• It is the intent of this course to touch basis on these

tools and not to study them in depth.

• Depth analysis of these theories is considered subject

for another course.