Paretto analysis.ppt

8/14/2019 Paretto analysis.ppt

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By carrying out a Pareto Analysis, themanager is able to focus on training as an

issue, rather than spreading effort overtraining, taking on new staff members,and possibly installing a new computersystem.

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2. FlowchartsFlow charts are easy-to-understand

diagrams showing how steps in a

process fit together. This makes them useful tools for

communicating how processes work,and for clearly documenting how aparticular job is done.

Furthermore, the act of mapping aprocess out in flow chart format helpsyou clarify your understanding of theprocess, and helps you think aboutwhere the process can be improved.

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A flow chart is used to

Define and analyze processes;

Build a step-by-step picture of the processfor analysis, discussion, or communication;and

Define, standardize or find areas forimprovement in a process

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How to make a flow chart

Most flow charts are made up of threemain types of symbol:

Elongated circles, which signify the start orend of a process;

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Rectangles, which show instructions oractions; and

Diamonds, which show decisions thatmust be made

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Within each symbol, write down what thesymbol represents.

This could be the start or finish of theprocess, the action to be taken, or thedecision to be made.

Symbols are connected one to the other

by arrows, showing the flow of theprocess.

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Points to note

Flow charts are simple diagrams thatmap out a process so that it can easilybe communicated to other people.

To draw a flowchart, brainstorm thetasks and decisions made during aprocess, and write them down inorder.

Then map these out in flow chartformat using appropriate symbols for

the start and end of a process, foractions to be taken and for decisions

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Finally, challenge your flow chart to makesure that its an accurate representation

of the process, and that that it representsthe most efficient way of doing the job

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3. Check sheets

The intent and purpose of collectingdata is to either control the productionprocess, to see the relationshipbetween cause-and-effect, or for thecontinuous improvement of thoseprocesses that produce any type of

defect or nonconforming product.

A Check Sheet is used for the purposeof collecting data to compile in such away as to be easily used, understoodand analyzed automatically.

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The Check Sheet, as it is beingcompleted, actually becomes a

graphical representation of the data youare collecting, thus you do NOT need anycomputer software, or spreadsheet torecord the data.

It can be simply done with pencil andpaper

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The main functions -

Checks

Production process distribution checks -where the distribution lies.

Defective item checks - to determinewhat kind of defects exist in the process.

Defect location checks - to determinewhere the common defects on a part are

located.

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Defective cause checks - type of defectand thus validate the cause thereof.

Check-up confirmation checks - finalphase of assembly to check the finishedproduct or work.

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4. Histograms

The common person believes that if apart is made in mass production froma machine, all of the parts will beexactly alike.

The truth is that even with the best of

machines and processes, no two parts are

exactly the same. The product will have a main or "mean"

specification limit, with plus/minus tolerance

that states that as long as the part is

produced within this range, to that range, it is

an acceptable part.

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The object is to hit the targetspecification, however, that is notalways totally possible.

The purpose of a Histogram is to takethe data that is collected from aprocess and then display it graphicallyto view how the distribution of thedata, centers itself around the mean,or main specification.

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The histogram will graphically

show

The center of the data.

The spread of the data.

Any data skewness (slant, bias or run atan angle).

The presence of outliers (product outsidethe specification range).

The presence of multiple modes (orpeaks) within the data.

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5. Scatter diagrams

The Scatter Diagram is another QualityTool that can be used to show the

relationship between "paired data",and can provide more usefulinformation about a productionprocess.

What is meant by "paired data"? The term "cause-and-effect"

relationship between two kinds of datamay also refer to a relationshipbetween one cause and another, orbetween one cause and several

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For example, you could consider therelationship between an ingredient

and the product hardness; betweenthe cutting speed of a blade and thevariations observed in length of parts;or the relationship between the

illumination levels on the productionfloor and the mistakes made in qualityinspection of product produced.

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6. Control charts

Control charts are generally used in aproduction or manufacturing environment

and are used to control, monitor andIMPROVE a process.

Common causes are always present andgenerally attributed to machines, material

and time vs. temperature.

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This normally takes a minor adjustmentto the process to make the correction

and return the process to a normaloutput.

However, when making a change to the

process, it should always be a MINOR

change.

If a plot is observed that shows a slightdeviation trend upward or downward,the "tweaking" adjustment should be a

slight change, and then another

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Too often people will over-correct bymaking too big of an adjustment which

then causes the process to dramaticallyshift in the other direction.

For that reason, all changes to theprocess should be SLIGHT and GRADUAL!

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Control Lines

A control chart is a graph or chart withlimit lines, called control lines.

There are basically three kinds of controllines:

the upper control limit (UCL),

the central line (actual nominal size ofproduct),

the lower control limit (LCL).

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The Xbar & R Control Chart

An Xbar & R Control Chart is onethat shows both the mean value (X ), and the range ( R ).

The Xbar portion of the chart

mainly shows any changes in themean value of the process, whilethe R portion shows any changes

in the dispersion of the process.

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This chart is particularly useful inthat it shows changes in meanvalue and dispersion of the

process at the same time, makingit a very effective method for

checking abnormalities within theprocess; and if charted while inprogress, also points out a problemin the production flow in real time

mode.

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7. Fishbone diagram

Cause & Effect Diagrams

Identifying the Likely Causes of Problems

Also called Fish or Fishbone Diagram andIshikawa Diagrams

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Cause and Effect analysis helps you tothink through causes of a problem

thoroughly. Their major benefit is that they push you to

consider all possible causes of theproblem, rather than just the ones that are

most obvious

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Conclusion.

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Paretto analysis.ppt