Lect 1 Thoery Class

8/8/2019 Lect 1 Thoery Class

1/19


2/19

Introduction to some jargonsy Process

y Mean value

y Standard deviationy CV %

y Attribute data

y Variable data

y P-value


3/19

Why Charts and graphs

y Visualization of data

y Easy troubleshooting by allocating the problem in thegraph

y Flexible accessibility to huge amount of data on asingle sheet

y Easy decision making


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BackgroundTypes of variation

Processvariation

Test methodvariation

Commonvariation Specialvariation

*Differentiation of common cause of variation and special cause

of variation

Operator

related issue

Machine

related issue


5/19

The concept


6/19

The concept


7/19

Six sigma

yWhat is six sigma

y The 3.4 defects ppm conceptyWho is the inventor of this all

yWhat is the reason of getting it more and morepopular


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The companies achieved 6 sigmay The list can be retrieved at

http://en.wikipedia.org/wiki/List_of_Six_Sigma_companies

y Some examples

y Amazon.com Dell DHL Ford G.E Honeywell

y Kraton polymers PIA PSO

y McGraw Hill United states army


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DMAICy Define the problem

y Measure the data from the process

y Analyze the problem and find the root causey Improve the process based on analysis

y Control the process


10/19

Process analysis using chartsy Two fundamental types of charts for SPC

Run charts Control charts


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How to differentiate common and

special causes of variationy Common cause variation:

y It is inherent in process

y Produced my multiple interactions between processvariables

y The collection of variables and their interactions iscalled system of common causes.


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How to differentiate common and

special causes of variation

y Variation in the process that is assignable to a specific

cause or causes

y This type of variation arises because of specialcircumstances


15/19

Actions to take immediately on

finding some variationy Immediately try to understand when a special cause

occurred.

yDetermine what was different when the special causeoccurred

y Identify ways to prevent the special cause fromrecurring

y Actions:y Immediately make basic changes in process


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Control chartsy These are the graphical display of the process stability

and instability.

y Process stability: certain degree of consistency

y Process consistency: process in control limits of 3

sigma


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Reason for using control charts

y Monitor process variation over time

y To find the effectiveness of changes in processy Differentiate between special and common cause of

variation


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Run charts and control charts

y Control charts like run charts display data in time

sequencey Control charts are more efficient in assessing and

improving process stability.


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Types of control chartsy One type is that displays the attribute data and the

second one displays the variable data.

y Generally used types of control charts

y X bar and Rcharts

y Individual and moving range charts

Lect 1 Thoery Class

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Transcript of Lect 1 Thoery Class