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7QC
TOOLS
TOOLS -OC
Prepared By: Mr. Prashant S. Kshirsagar
(Sr.Manager-QA dept.)

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Quality Improvement: Problem Solving
-: O
.b,',}.ect,.ve ., trai..ning:-
• Present an overview of Seven Quality
Tools
• Address purpose of each QC tools
• Address application in problem solving
• Address benefits of each tool

-: Rules for training :
Participate,
,t,J

-:Ba ckground and Importance of 7 OCtools:
Tbe 7 QC tool.sare simple statistical
tools used for problem solving. Tbese
tools were either developed in Japan or
introduced to Japan by the Quality
Gurus such as Deming and Juran.
Kaoru Ishikawa has stated that these 7
tools can be used to solve 95% of all
problems.
The 7 Tools of Quality is a designation
given to a fixed set of graphical
techniques identified as being most
helpful in troubleshooting issues related
to quality. They are used to analyze the
production process, identifv the major
problems, control n uctuationsof
product quality, and provide solutions
to avoid future defects.
7
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Why 7QC Tools?
The Deming Chain
Improve Quality
Decrease Costs
Improve Productivity
Decrease Price
Increase Market
Stay in Business
Provide More Jobs
Return on Investment

-: 7 Quality Control Tools:-
,. Check sheets
2. Stratification
3. Pareto chart
4. Cause and
effect diagram
s. Histogram
6. Control chart
7. Scatter diagra1n

-: POCA APPROACH:-
W HAT Defin i tion of pr oblem
WH Y Analys is of pr oblem
HOW Identification of causes
Planning countermeasure
DO I mplementation
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Q U A L I T Y

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Q U A L I T Y

: 1st Quality tool: Check Sheet :
Source of Incoming Model Home Traffic
Check Sheet
I Tuesday Wednesday I Thursday Friday Total
I Monday
DallyNewspaper
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Newspaper Ads 111 11 I 11
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Quality Improvement: Proble mSolving

Purpo se:-
-•
• Check Sheet •
•-
• Tool for collecting and
organizing measured or counted
data
• Data collected can be used as
inputdata for other qualitytools
►DataCollections a re based 011
answeri11g the questions of What,
Where, Who and How
When to Use a Check Sheet?
-To collect data repeatedlyby the
same person or ai thesame location.
-To colJectdata on the frequency or
patterns of events. problems, defects,
defect location, defect causes,etc.
-To collect data from a production
process.
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-••Check Sheet ••-
-: C hec k S heet P rocedure :- ;-----
-Decide what event or problem will be
observed. Develop operational
definitions.
-Decide when daia will becollected
and for how long.
-Design the fonn. Set it up so that data
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can be recorded simply by making
check marks or Xs or similarsymbols
and so that data do not have to be
recopied for analysis. Label all spaces
on the fonn.
- Test the check sheet for a short trial
period to be s ure it collecis the
appro priate data and is easy to use.
Eacb time the targeted event or problem
occurs, record data on tbe checksheet.
1 Check Sheet.xlsx Totol It 19
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Benefits: -: Check Sheet .
•-
• Collect data in a systematic and
organize dmanner
• To determine source of problem
· To faciJitate classification of data
(stratification)
· The check sheet is a simple and
effective way to display data.
• 1t provides a uniform data
collection
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TotalDef
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-: 2nd Quality Tool:
Stratification :-
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Stratification is a system of formation of
layers, classes, o r categori es.
Data collected using check shee ts need to be
meaningfully class ified. Such classification
helps gaining a preliminary
understanding of relevance and
di spe rsio nof data so that further analysis
can be planned to obtain a meaningful
output. Meaningful classification of data is
called stratification.
This technique separates the data so that
patterns can be seen.
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When to Use S tratification?
- When data come from several sourecs or
conditions, such as shifts, days of the week,
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suppliers or populat iongroups.
-When data analysis may require
se11arating different sources or conditions. I!!!!!!!!!!!!!!

-: Stratification :-
Sh·atification Procedure :-
-Before collecting data, co ns ider which
information about the sources of the data might
have an effecton the results. Set up the data
collection so that you collect that information as
well.
-When plo tting or graphing the collec ted darn on
a scatter diagram, control cha11, histogram or
other analysis tool, use dilferent ma rks or colors
to distinguish data from various sources. Data
that arc distinguished in this way arc said to be
"stratified."
-Analvzc the subsets of stratilied data separately.
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-Example: I) Variation of object in two different
machines 2) Age stratification of two different
country 3) Division of society, etc.
2 Stratificationdiagram.xlsx Lowerdau

-: 3 Quality tool: Pareto Chart:-

-: Pareto Principle:-
• Vilfredo Pareto (1848-1923) Italian
economist developed this princip le.
• 20% of the population has 80% of
the wealth
• Juran used the term "vital few, trivial
many". He noted that 20% of thequality
problems caused 80% of the dollar loss.
• Purpose: The purpose of a Pareto
diagram is to separate the significant
aspects of a problem fron1 the trivial
ones.
7QualyTools

-:Use of Pareto Chart:-
• Pareto charts help teams focus on the
small number of really important
problems or their causes.
• They are useful for establishing
priorities by showing which are the
most critical problems to be tackledor
causes to be addressed.
• Pareto chart helps teams to focus their
efforts where they can havethe
greatest potential impact.
• When communicating with others
about your data. T
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-: Pareto Chart Procedure:
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1. Develop a list of proble ms. itemsor
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2. Collect the data as per defined time
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3. Tally, for eac h item, how often it occ
urred. Detennine the grand total
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orall items.
4. Find the percent of each item.
5. List the items being compared in
decreasing order of measure of
comparison: e.g., the most frequent to 8l t
he least frequent. The cumulative %
for an item is the s um of that item's
percent of the total and that of all the
other items that come before it in the
ordering by rank.
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-: Pareto Chart Benefit:-
6. List the items on the horizonta l axis of a
graph from highest to lowest. Label the left ioo
vertical axis with the numbers, then label 1411
the right vertical axis with the cumulati ve% lO
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Draw in the bars for each item.
7. Draw a line grap h of the cumulative %. no
Thefirst point on the line graph should line 18
up with the top of the first bar.
8.Analyze the diagram by identifying most
critical items
3Pareto chart.xlsx
Benefits:
■ Pareto analysis helps graphically display
results so the significant few problems
emerge from thegeneral background
■ It tells you what to work on first

-: 4 Quality Tool: Fishbone diagram :
Fishbone Diagram: Employee Turnover
O<gonlDllonat
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-: Fishbone diagram :-
The cause and effect diagram analysis was first developed by Professor Kaor11 l s flika111aof the
Unive rsity of Tokyo in the 1940s', is also known as the ' Fishbone Diagra m' or the ' Ishikawa
Diagram' or the ' Ca use-and-Effect Diagram•.
Description • The fishbone diagram identifies many possible causes for an efTector problem.
It can be used 10stn,cture a brains1omi1ng session. It immediaiel y sorts ideas into useful
categor ies.
When to use a Fishbonc Diagram'?
- When identifying possible causes fora problem.
Especially when a team·s thinking tends to fall
into nots.
Fishbone Diagram Procedure -
I) Br a instorm the major ca tegories of causes
of the problem.
2) It can be identify by '6M' techniques:
i) Methods
ii) Machines (Eq uip ment)
iii)Manpower (People)
iv) Materials
v) Measurement
,•i Mana cmcnt Environment... etc
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-: Fishbone diagram :-
3)Write the categories of causes as
branches from the main arrow.
4) When you are brainstorming causes,
consider having team members write each
cause on sticky notes, going around the
group asking each person for one cause.
Ask: " Why does this happen?" Continue
going through the rounds, getting more
causes, until all ideas are exhausted.
Causes can be wrinen in several places if
they rela tetoseveral categories.
5)Analyze causes and eliminate trivial
and/or frivolo us ideas.
6)Rank causes and circle the mostlikely
ones for further consideration and study.
7) Investigate the circled causes.
4 Fishbonediagram.xlsx
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Bene ftis:
• Breaks problems down into bite-size
pieces to find root cause
• Fosters/Encourage team
work/participation
• Common understanding of factors causing
the problem
• Road map to verify pictw·e of the process
• Follows brainsto rmi11grelationshi p
• Indicates possible ca uses of variation
• l ncreases process knowledge
• Diagram demonstrates knowledge of
problem solving team
• Diagram is a guide for data collection
-: Fishbone Diagram •-

-•
• 5 Quality tool: Histogram •
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• Description - -• Histogram •-
Histograms are graphs of a distribution of data designed to show center ing,
dispersion (spread), and shape (relative frequency) of thedata.
They are used 10 understand how the output of a process relates to customer
expectation s (targets and specifications). and help answer the question: "Isthe
process capable of meeting customer ...•••••<>o--1"1.,..,,-,N-m•I -,,,,.,...,.,..,.,.'° _.,..,,.,,Cu"' '"'
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I) When the data are numerical. ,·,- . .. .. n,,.,. ... .. ...
2)When you want to see the shape of data's distribution
3) Whether the output of a process is distributed approximately nonnally.
4) When analyz ing whether a process can meet the customer's requirements.
5) When analyzing what the outp ut from a supplier's process looks like.
6)When seeing whether a pro cess change has occurred from one time period to
another.
7) When determining whether the outputs of two or more processes are different.
8)When you wish to communicate the distribution of data quickly and easily to
others.

-: Histogram :-
Constructing a Histogram
Step 1 - Count number of data points
Step 2 - Summarize on a tally sheet
Step 3 - Compute the range
Step 4 - Determine number of intervals
Step 5 - Compute interval width

-: Histogram :-
s tep 6 - Determine in terval sta rtflng
points
Step 7 - C1
ou11tnum ber of points in
e ach interval
Ste p 8 - P
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Ste p 9 - Add title and leg,end
S Bistogram.xlsx

-: Histogram :-
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-: Interpretationof Histogram:-
+- TmgetValue
(NominalSpecification)

-: Histogram :-
Definition s :
c.=ProcessCapability. Asim ple and stra
ightforward indicator of process capability. Cpk=
ProcessCapability Index. Adjustment
of C
P fortheeffect of non-cente reddistribution.
Inter preting Cpk :-
·•c•kisan index (a simple number) which measures
how close a process isrunning to its specifica tion
limi ts. relative to the natural variability of tbe
process. The larger the index, the less like ly it is
that any item will be o uts ide the specs."
Example: " If you hunt our shoot ta rgets with bow,
darts, or gun try this analogy. If your shots are
folling in the same spot forming a good group this
is a high •c.and when the s ightin g is adjusted so
this ti g ht g ro up of s hots is la ndin g on th e bulls
eye. you now have a high C••·"
"You must have a CP•of 1.•33 (4 sigma( or
high er to sa tisfy most customers."
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Benefits:
-: Histogram :-
• Allows you to understand ata
glance the variation that exists
ma process
• The shape of the histogram will
s how process behavior
• Often, it will tell you to dig
deeper for otherwise unsee n
causes of variation.
• T he s hape and size of the
dispersion will he lp identify
otherw isehidde n sources of
variation
• Used to determine the
capability of a process
• Starting point for the
improvement process
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-: 6 Quality tool: Control Chart :-
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-: Control Chart :-
, Purpose:-
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The control chart is a graph used to
study how a process changes over
time.
, Guidelines:-
A control chart always has a central
line for the average, an upper line for N-
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the upper control limit and a lowe r line I?
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for the lower cont:rol lintit. These lines !7
are determined from historical data.
By comparing current data to these
lines, you can draw conclusions about
whether the process variation is
consistent (in control) or is
unpredictable (out of control. affected
b s ecial causes of varia tion.
I 2 3 4 5

-• Control Chart •-
►
W
hen to Use a C on t rol C hart :-
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- When controlling ongoing processes by
finding and correcting problems as they
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outco mes from aprocess.
-When determining whether a process is s
table (in statistical control).
-When analyzing patterns of process
variation from special causes(non-routine
events) or common causes (built into the
12rocess).
- W hen determining whetheryour qua lity
' ' ' . ' ' '
improvement project sbould aim to prevent
s12ecific 12roblems or to make fundamenta l c
ha nges to the 12rocess.
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-: Control Chart :-
►
Co
n
tr
o
l Chart Basic Procedure :-
I. Choose the appropriate contro l chart for ,=.
your data. - '
2..Dete rmine the appropriate time period for
collecting and plotting data.
3.Collect data, construct your chart and
analvze the data.
4.Look for"out-of-control signals" on the
control chart. When one is identified, mark
it on the chart and investigate the cause.
Document J,0111youinvestigated, 1
1
1
!
,{lfyou
learned, the cause and l,0111it1
1
1as
corrected.
5. Continue to plot data as they are
generated. Aseach new data point is plotted,
check for new out-of-control signals.
6 Controlchart.xlsx
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-: Control Chart :-
Strategy for e liminating
assignable/Special cause (i.e.
unpredictable errors) variation:
Get timely data so that you see the
e ffect of the assig nable cause soon
after itoccurs.
As soon as you see something
ind icates that an assigna ble cause of
variation has happened, search for
the cause.
Change tools to compensate forthe
Strategyfor reducing common
cause (i.e. Predictable errors)
variation:
Reducing common-cause variation
usually requires making fundamental
changes in your process
Addressing the common cause
variation will improve the process
performanc.e
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Benefits:
-: Control Chart ·
•
• Predictprocess out of control and out of X
specification limits
• Distinguish between specific. identifiable ..
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causes of variation
• Can be used for statistical process control
• Control charts allow operators to detect
manufacturing problems before they
occur, this greatly red uces the need for
product rework or additional product , "
'
1
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expenditures.
• Control charts se rve as the early warning
detection system, telling you that now is
the time to go in and make ac hange.
• Afler analyzing a control chart,operators
need 10 determine whether to"do
something" (i.e. adjust a behavior in the
proce.ss) or "do nothing ." (i.e. let the
process run asis).
- ·
- - - - - - - - • +- - l[
X

-: 7th Quality tool: Scatter Diagram :-
S
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-: Scatter Diagram :-
Purpose:
To identify the correlations that
might exist between a quality
characteristic and a factor that
might be driving it
y
....
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.z;,.•
.,a•••
--
-
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X
A scatter diagram shows the
correlation between two
variables in a process. These
variab les cou ld be a Critical To
Quality (CTQ) characteristic.
Dots representing data points
are sc"ttered on the diagram.
•
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•
•
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-: Scatter Diagram .
•-
Procedure: How is itdone?
Decide whic h pa ired factors you want to
examine. Both fac tors must be
measurable on some incremental linear y
sca le.
Collect30to100 paired data points.
Find the highest and lowest value for
both variables. y
X
Draw the vertical (y) and horizontal :
(x) axes of a graph. .5
.
a
Pl o t tbe data 0
•
u
Title the diagram ct
7 scatter plots.xlsx
The sitape that the cluster of dots takes will tell
you something about the re/ati o11sltip between
the hvo variflbles thM yo u tested. N
u
mborSold '

-: Scatter Diagram :-
- ' I .
_
:::
P os itl w conelatlon
, .:$: ;:·
•
P ositive corretotlon
m • y b o p '". . "'
Ifthe variables are
c
o
rrelated, when one , .,#'"
changes the other •
probably also changes.
Dots that look like they
are trying to form aline
are stronglycorrelated.
Speed(mphl
y
.
N4t9t1t1ve•
corr.l oti on
m a y p r - . . n t
Sometime s the scatter .
plot may show little
correlation when allthe
data are considered at
once.
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