Transcript
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Business Unit
Hindustan Zinc LimitedRCA Workshop
Strict ly Privateand Confidential
1 June 2013
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Problem Solving Tools or 7 Basic Quality Tools are the
techniques used for continuous improvement…
ProblemSolvingTools
Root Cause Analysis
Histogram
ParetoDiagram
ScatterDiagram
Stratification
Check Sheets
Graphs &Control
Charts
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The Concept of a Root Cause
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What do we mean by “Problem”
Technically, deviation from desired specification.
In general, deviation from expectation.
Concept
Example
1. Machine Breakdown
2. Delay in spares delivery
3. Operator absenteeism
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What do we mean by “Cause”
One of the attributes that is responsible for the occurrence of theproblem
Concept
Can we eliminate the problem by addressing the cause ?
Probably No Why ?
There can be many causes for a problem!!!!!
Then how can we eliminate the problem?
By addressing the ‗root cause‘
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Why “Root cause”
That is the cause from which the problem originates
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The origin of Root cause analysis technique
The development of root cause analysis can be traced back to the 70s when a cognitivepsychologist named James Reason expounded on the analysis of human error.
His studies led to the conclusion that:
• Most errors occur due to ‗lack of clear and definitive specifications aboutplans of actions’
As a result, human errors occur when the doer of the action tends to functionautomatically and, at times, performs while in a state of absent-mindedness
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Professor Reason‘s logic w as so widely received that he became one of the leading innovators of tools for improving patient safety inthe health care industries.
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Corrective and preventive actions
Concept
Normal
state
Problem
(Break down,delay etc)
Corrective action
Root Cause Preventive action
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How can we eliminate Root cause
Some of the commonly used tools are
1. Why-Why analysis (When the causes are restricted to one or two)
2. Fish Bone diagram (When the causes are many)
RCA Tools
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What is “Why-Why analysis”
• It is a method of asking ―Why‖ over and overagain till one reaches a root cause.
• Normally, root cause gets identified within 5times of asking ―Why‖
• Identifying the symptom/condition for theoccurrence of abnormality, is veryimportant.
• The best person to identify the root cause isthe one who attended the problem.
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Cause
Cause
Cause
Cause
Root Cause
Problem ...Why
because... Why
because... Why
because...
because...
because...
Why
Why
Why
Problem
Cause 1 Cause 2 Cause 3
Why 1
Why 2
Why 3
Symptom Verification
"If you don't ask the right questions, you don'tget the right answers‖
Root Cause
Procedure
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*The 5-Why approach, created by Sakichi Toyoda (1867 - 1930), the founder of Toyota, is a simple w ay to begin any investigation
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Advantages of Why-why technique
A major advantage to the 5 Why technique is
• It is relatively easy to use and apply
• Its easy application makes it a practical tool for root cause analysis in problem
solving
• Through this approach is possible to get to root causes in a relatively shortperiod of time.
Caution: Ease of use and speed need to be balanced with the risk of failurefrom recurrence of the problem (should the 5 Whys fail to find the true rootcause)
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Let us understand the Why-Why analysis processthrough some examples
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A simple why-why analysis-Example 1
PROBLEM: My car won’t start.
WHY BECAUSE…
Why won’t my car start? The battery is dead.
Why is the battery dead? The alternator did not charge the battery.
Why didn’t the alternator charge the battery?
The alternator belt was slipping.
Why is the belt slipping? The belt is worn.
Why is the belt worn? The owner did not have the belts replaced asscheduled.
Why didn’t the operator have the beltsreplaced?
The owner was unaware of the maintenanceschedule.
Countermeasure: The owner will read the owner‘s manual to become familiar with therecommended maintenance. The owner will also refer to the manual every 10,000 miles.
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Example
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How a car battery is charged
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Example 2
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PROBLEM: Cylinder does not operate smoothly
WHY BECAUSE…
Why cylinder does not operatesmoothly
Strainer was clogged
Why Strainer was clogged Oil was dirty
Why oil was dirty Dirt entered the tank
Why does dirt get in Upper plate of tank has hole andgap
Why was hole made Repair work during maintenance work
STANDARDIZE THE REPAIR WORK
Example
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Example 2 Continued..
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PROBLEM: Cylinder does not operate smoothly
WHY BECAUSE… ACTION
Why cylinder does notoperate smoothly
Strainer was clogged Clean the strainer
Why Strainer wasclogged Oil was dirty Drain and clean
Why oil was dirty Dirt entered the tank Prevent scattering of chips& cutting fluid
Why does dirt get in Upper plate of tank hashole and gap
Plug hole and gap
Why was hole made Repair work duringmaintenance work Standardize repairs
What is your immediate action? Cleaning the strainer
What is your final action ? Standardize repairs
After cleaning the strainer, is it OK Yes
Examples
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Complex why-why analysis
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Background:
Production Manager, Sunil, is heading out to the production floor. He sees thathis highest priority line is down again. ―What is it this time?‖ he asks. His topmechanic replies, ―We are down for a conveyor. We‘ll be back up soon, if wehave the right sprocket.‖
Sunil decides to do a 5 why analyses even though this appears to be a simplefix. In the old days they might have been satisfied with replacing thesprocket. Today, Sunil wants to make sure that the replacement does not failprematurely. He wants to address the root cause.
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Procedure to carry out a complex 5 why analysis
• The difference with the Multiple Path 5 Why is that there will be more thanone answer to some or all of the why‘s.
• Include the answers that are contributing to the issue (If sufficient proof isavailable). The 5 Why can spin out of control and become too complex if youinclude every conceivable possibility.
• If there is a doubt relating to the applicability of the cause, capture the ideaand verify if the condition exists.
• For example, if someone says, ―maybe the bearings have not been properly
lubricated.‖ Capture the idea and verify the condition of the bearing. Ifthe bearing hasn‘t been lubricated properly, include it in your Root Cause Analysis.
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Example
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Example of a Complex why-why
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SprocketBroke
WrongSprocket
Excessivestress
Line speed >Design speed
Worn out bearing
Correctsprocket wasout of stock
DirtyConveyor
Conveyor in-houseline modification
No change as perPM
Inaccurateinventory
No cleaningschedule
Timely order wasnot placed
New mechanic.Unfamiliar with
line changes
After modificationthe new conveyornot added to PM
Lead time high.Part inventory is
overdue
Parts usage is notconsistentlydocumented
Example
Why-Why
Example
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Root cause and countermeasures
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Conveyor notincluded in cleaning
schedule
Modify thecleaning schedule
to include theconveyor.
Designateresponsibility for
cleaning.
Conveyor not addedto PM schedule
Add toPMS/CMMS
System failed todocument part usage.
Timely order was notplaced
Regulardocumentation
/Implement partsusage form to be
used on all shifts.
Min. Inventorylevel and Re order
levels to bedefined.
CountermeasuresRoot causes
Example
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“If you don’t have time to do it right, will you have timeto do it over?”
If you don’t have the time to address the root causesnow, you will likely be dealing with the same issues
again.
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Concept
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Fish bone diagram procedure (Ishikawa or Cause andeffect diagram)
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Step 1: Capture issue or problem and represent that in a box.
Step 2: Draw a line from the box across the paper or white board (Forming the spine of the fishbone)
Step 3: Draw diagonal lines from the spine to
represent categories of potential causes.
Step 4: Draw smaller lines connecting spine line torepresent deeper causes.
Further analysis is needed to validate the actualcause, ideally with data.
Note: Brainstorm potential solutions once the actual causehas been identified
Step 5: Identify which deeper cause impact onmaximum events data, 80/20 principle and landin root cause
Problem
Problem
Problem
Cat egory 1Category 3
Ca tegory 2Category 4
Problem
Cat egory 1Category 3
Ca tegory 2Category 4
Problem
Ca tegory 1Ca tegory 3
Ca tegory 2Ca tegory 4
20% ofattributes
cont ributing t o80% of the
problem
Concept
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Some important points related to Fishbone analysis
• A fishbone starts with just one, single problem which doesn't reflect thenature of real world issues.
• It reads right to left because the Japanese language reads that direction.
• It mixes causes and possible causes without specifying evidence.• It breaks apart the fundamental cause-and-effect relationships within
an issue by grouping the causes into general categories.
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The fishbone is widely recognized as one of the standard quality tools.Ishikawa was a pioneer with his approach.The fishbone cause-and-effect diagram is part of every six-sigma program.*Cause Map is a more exhaustive approach
Project Charter
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Example 4 – Live case in RA mines
Project Charter
PROJECT CHARTER
General Information
Project NameReduction of REL Drill(No-19 to 26) engine related
breakdown by 50%Note: Average monthly breakdown: 1139hrs
Team Name
NL Panchal (L)Rakesh Khurana (M)SK.Hussain (M)Shiva Kumar (M)
Project Sponsor Project Location Project no. Ver No. Date
HEMM FIP/Drill/-01 09.10.2012Project Details
Problem Statement Engines of drills(19-26) alone contributes major downtime (48% of total downtime)
Goal Statement Improvement of REL Drill (no-19 to 26) availability by ~ 9% from the base line of 54%.
Constraints 1. Spares parts support from OEM , 2. Inadequate skill level of maintenance crew.
Project Scope Engine and engine Accessories failure.
Resources - Team membersName Role Dept/Function Name Role Dept/Function NL Panchal Leader HEMM MemberRakesh Khurana Member AO-Cell Member
Sahid Hossain Member HEMMShiva Kumar (REL) Member REL
MemberMember
Benefits Project Review Schedule
Bottom LineBenefits (KPI)
Operational KPI:Drill Availability : ~ 9%In terms of meters: ~ 7812/month
Activity Target Date Actual date Start 05.10.2012
[D] Define
Strategic benefits
Blasted inventory will
increase=7812*49MT=382788MT/month
[M] Measure
[A] Analyse [I] Improve
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Measure
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Data analysis on problems related to breakdown of
Drills (19-26)
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100%
46%
20%
0%
20%
40%
60%
80%
100%
120%
Total
scheduledhrs
B/d hrs Engin e
relatedfailure
Total SD =
29376 hrs
5922
17431 676
1573
1 088
472438
41 941 4 316177
1566 40
1000
2000
3000
4000
5000
6000
7000
E n g
i n e
M a
i n t e n a n c e
R o
t a r y g e a r
b o x
D r i
l l t o o
l s
H y
d r a u
l i c
O t h e r s
C o m p r e s s o r
S t r u c
t u r a
l
E l e c
t r i c a l
U n
d e r c a r r
i a g e
P o w e r
t r a n s m
i s s
i o n
M e c
h a n
i c a l
O p e r a
t i o n
3635
851752
407
92 68 58 42 18
0
500
1000
1500
2000
2500
3000
3500
4000
Maximum breakdownhappens due to tripping
of engine (30%)
Total B/d =11940 hrs
Note: Charts represents last 6 months cumulative data (Apr-Aug 2012)Source: SAP
B / d t i m e i n h
r s
Attributes of failures
Measure
Analyse
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Why the engine trips frequently - RCA
Analyse
Engine trips frequently Why 1
becauseTemperature rises beyond threshold
Why 2
Low Pumppressure
because
External Oilcooler chokes
Why 4
Why 3 because Radiator chokes Why 3 because
But pump always runsclose to rated pressure
(Data)
Pump with lowrated pressure
Solution:Pump with increased pressurerating of 5000 PSI
Dust sticks andaccumulates
because Why 4
Oil sediments infin
because Why 5
Oil leaks from
Gearbox because Why 6
Solution - Permanent1. Bolt with thread sealant2. Tightening with torque wrench
and3. CLTI calendar
Mounting bolt becomes loose in jerky movements
because
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Note:
Rated Pressure : 3500 PSI
Required Pressure : 33 00 PSI
because
Why 5
Low Fan Speed because Why 3
Summary:Commissioning of Increasedpressure rated pump and a simple
bolt with thread sealant can arrestmajor part of tripping problem
Format
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PHENOMENON ANALYSIS FORM
Ref No:
Date:
Describe the phenomenon clearly:
Short term action:
W
H
Y
Why-1
Why-2
Why-3
Why-4
Why-5
Is there anything else to be checked?
Proposed preventive countermeasures Resp Due Dt Status
Change in work method/ training required
Routine activity
Predictive check
Preventivemaintenance
Modification
Others
Status
Agreed
Planned
Implemented
Effective
Following format helps you in doing a structured Why-Why Analysis
Format
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Exercise
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Phenomenon: A fire broke out in the Loom-shed (250 Looms). It took a long time for workmen to control the fire. It was later identified that it took 3 hours to control the fire which could have been controlled in 30 minutes.
They were not refilled for a longtime
No system of knowing when they were filled last time
Why it took abnormally long time to douse the fire
The machine operators couldn‘t use the fire extinguishers
The operators were not trainedon using fire extinguishers
All the fire extinguishers werenot working
What is the countermeasure inthis case ?
Why ?
Why ?
Why ?
Why ?
Why ?
Live case in a loom shed (Textile Plant)-Example 5
Exercise
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Guidelines
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Some of the expectations while doing RCA’s
• The process requires completehonesty and no predeterminedassumptions.
• Follow the Data! Don‘t try to lead it.
• Why-Why should be done only withcross functional team.
• Actual observations at the work siteneeds to be taken into considerationto arrive at the root cause
Guidelines
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Countermeasures
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What should be the outcome of Why-Why analysis
Single PointLesson
(Training/Knowledge
transfer)
Inclusion inPreventive/Predictive
Maintenance
schedule
EquipmentModification
VisualControl/MistakeProofing
Why-Why Analysis should lead to
Countermeasures
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Checkpointaddition/
modificationof CLTI
checklist
These are known as countermeasures.Countermeasure deployment is important to avoid
reoccurrence of the problem
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Limitations of the approach
• Using 5 Whys doesn‘t always lead to root cause identification when the cause isunknown. That is, if the cause is unknown to the person doing the problem solving,using 5 Whys may not lead to any meaningful answers.
• An assumption underlying 5 Whys is that each presenting symptom has only one
sufficient cause. This is not always the case and a 5 Whys analysis may not reveal jointly sufficient causes that explain a symptom.
• The success of 5 Whys is to some degree contingent upon the skill with which themethod is applied; if even one Why has a bad or meaningless answer, the wholeprocedure can be thrown off.
• The method isn‘t necessarily repeatable; three different people applying 5 Whys to thesame problem may come up with three totally different answers.
• 5 Whys requires skill to use well and most important, should be grounded inobservation, not deduction.(On-the-spot observation rather than deduction is the onlycorrect way to answer a ―Why?‖ question)
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Pit falls
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A common tendency while doing RCA’s
“ Operator error…‖
The question is-
Why people don‘t comply?
• Improper instructions
• Improper training
• Lost expectations/lowmotivation
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Headway
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Headway and expectations
Doing 5-why analysis will get imbibed into the culture only if the Manager demandsfor the 5-Why document during review of any critical abnormality (Breakdown,
Quality complaint etc from the daily management team)
y
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Don‘t limit the search !
It is important to know the answer to the following questions
• What role should management play?
• Are you looking beyond your own backyard?
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Why-why analysis-In a Nutshell
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Exercise
• Identify a repeatedly occurring problem that your unit is facing.
• Brainstorm on the issue with your team member on your table
• Present it to the rest of the team
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Action planning
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Why Detail Action Planning is Important.....?
One Night 4 college students were playing till late night and could not study for the test which was scheduled for the next day.
In the morning they thought of a plan. They made themselves look as dirty with greaseand dirt. They then went up to the Dean and said that they had gone out to a weddinglast night and on their return the tire of their car burst and they had to push the car allthe way back and that they were in no condition to appear for the test.
So the Dean said they could have the re-test after 3 days. They thanked him and saidthey would be ready by that time.
On the third day they appeared before the Dean. The Dean said that as this was a SpecialCondition Test, all four were required to sit in separate classrooms for the test. They allagreed as they had prepared well in the last 3 days
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Why Detail Action Planning is Important.....?
The Test consisted of 2 questions with a total of 100 Marks.
See Below for the question Paper
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Q.1. Your Name : ........ ......... ......... (2 Marks)
Q.2.. Which tire burst? (98 Marks)
a) Front Left b) Front Right
c) Back Left d) Back Right
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Action Plan – indicates details of all the things that must
be done to ensure a smooth and objective trial ofsolution / improvement
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The Action Plan should reflect aspects such as :
No. Task PriorityDue
Date
Assigned
to
Assigned
DateStatus Remarks
Who
What
When
Where
How
Maximizing Aids
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Formation of Action Points for Implementation
SN Action Plan Impact on Idea
Given by
Priority Status StartDate
EndDate
Resp Throughputimprovement (MT/mth)
1Furnace roof modification for PGP (Brick lininginstead of G lass wool) to reduce frequent glass
wool replacement
Availability -Breakdown
Bharat Priority 4
InProgress - OnTime
14-Apr14-
JunBharat 13
2
Roller Assembly to be m ade ready for
replacement to prevent loss time of assemblyduring stoppage. Rollers to be dynamically balanced
Availability -Shutdown Verma Priority 3
In
Progress - OnTime
14-Apr 30- AprSuryade v 43
3
Shutdown planning for cleaning & PM to bemade for Annealing every month. Entire plan to
be chalked out (To do list) - incorporate start upn cool down
Availability -Shutdown
Bharat Priority 1 Yet ToStart
20-Apr28-
AprBharat/ Verma
43
4 Annealing should be given a priority for thecrane usage to avoid any loss of time due tocrane availability
Availability -Material availability
VSC Priority 1
InProgress - On
Time
18-Apr - Bharat 50
5Discussion on increasing performance to beconducted
Performance Bharat Priority 1 Yet ToStart
28-Apr 5-MayBharat 58
6CNG gas usage in LPG & PGP to reduce thetemperature problem & cleaning time
Availability -Cleaning time -Temperaturereduction problem
VSC Priority 2
InProgress - OnTime
14-Apr15-
MayGautam 66
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Thank You
This publication has been prepared for general guidance on matters of interest only, and does not constitute professional advice. You should not act upon theinformation contained in this publication without obtaining specific professional advice. No r epresentation or warranty (expr ess or implied) is given as to theaccuracy or completeness of the information contained in this publication, and, to the extent permitted by law, [insert legal name of the PwC firm], it s members,employees and agents do not accept or assume any liability, re sponsibility or duty of c are for any consequences of you or anyone else acting, or r efraining to act,in reliance on the information contained in this publication or for any decision based on it.
©[Year] [insert legal name of the PwC firm]. All rights reserved. In this document, ―PwC‖ refers to [insert legal name of the PwC firm] which is a member firmof Pric ewaterhouseCoopers International Limited, each member firm of which is a separate legal entity.
Remember : It’s a journey of Continuous Improvement
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Problem Solving Tools or 7 Basic Quality Tools are the
techniques used for continuous improvement…
ProblemSolvingTools
Root Cause Analysis
Histogram
ParetoDiagram
ScatterDiagram
Stratification
CheckSheets
Graphs &Control
Charts
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Why use it?
To focus on the
problems/issues that offergreatest potential for
improvement
What does it do?
• Helps identify ―the vital few‖ from
―the trivial many‖
• Displays the relative importance ofproblems in a simple graphical way
• Helps in prioritizing efforts for
improvements
0
20
40
60
80
100
120
140
C B D D A F
0
20
40
60
80
100
120
Pareto Chart
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How To Construct A Pareto Chart
Total the data on effect of each contributor, and add these to determine the grand total
Re- order the contributors from the largest to the smallest.
Determine the cumulative percent of total
• For example, the cumulative percent of total through the fifth contributor is the sum of the
effects of the first five in the rank ordering, divided by the grand total, and multiplied by 100Draw and label the left vertical axis
• Label the axis from 0 to the grand total or just beyond.
• Provide a caption to describe the measure being used.
Draw and label the horizontal axis
• Divide the axis into as many divisions as there are contributors.• List the contributors from largest to smallest, going from left to right
• Provide a caption to describe them.
• If the contributor names are long, label the axis A,B,C, etc. and provide a separate key
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How To Construct A Pareto Chart
Draw and label the right vertical axis.
• Label the axis from 0 to 100%.
• Line up 100% with the grand total on the left axis.
• Provide the caption: ―Cumulative-Percent of Total.‖
Draw bars to represent the magnitude of each contributor‘s effect. • The height of the bars corresponds to the magnitude of that contribution as measured on the left
axis.
Draw a line graph to represent the cumulative-percent of total.
• The plotted points correspond to cumulative-percent as measured on the right axis.
• Line up the points above the right-hand edge of the bars.
Analyze the diagram.• Look for a break point on the cumulative percent graph.
• Review the interpretation section for more details.
Title chart: Label the ―vital few‖ and ―trivial many‖; and show the cumulative percent contributionof the vital few.
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Problem Solving Tools or 7 Basic Quality Tools are the
techniques used for continuous improvement…
ProblemSolvingTools
Root Cause Analysis
Histogram
ParetoDiagram
ScatterDiagram
Stratification
CheckSheets
Graphs &Control
Charts
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Scatter Plot – To find a correlation between paired
data… What is it?
• A graphical representation highlighting interaction of data points – usually between anindependent & a response variable.
Why use it?
• To show a possible relation between dependent & independent variables.
• To study & identify possible relationship between an output & an input variable. The outputis called the dependent variable & input is called independent variable.
• E.g.. Printing errors & printing speed; machine downtime & machine speed, monthlyproduction & absenteeism etc.
Purpose
• Makes it easier to determine a direct relationship, & hence the cause behind an effect.
• Helps in taking decisions for improving the process, by providing both visual & statisticalmeans.
• Provides both visual &statistical means to test the strength of a potential relationship.
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Based on the scatter diagram, the type of correlation
can be identified…
X
Y
+ve correlation(Y Increase asX Increases)
No correlation(Y Has no Particular
Relationship)
X
Y
-ve correlation
(Y Decrease asX Increases )
X
Y
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How to construct a scatter diagram…
• Obtain the table of raw data &determine the high & low values for each variable.
• Go to ―Insert‖ – Scatter.
• Select the ―Scatter with only
markers‖.
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Scatter Diagrams…
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• If the variables are correlated, when one changes the other probably also changes.
• Dots that look like they are trying to form a line are strongly correlated.
• Sometimes the scatter plot may show little correlation when all the data are considered at
once.
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Scatter plots
Exercise:
Two different variables have been shown below
• Personal Expenditure
• Personal income
What inference can be drawn from
the data set ?
Comment on type of correlation.
Where it can be used in your domain.
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Year Per. Cusp. Per. Income
1965 450 550
1966 500 600
1967 520 650
1968 560 720
1969 600 780
1970 650 850
1971 700 9001972 780 1000
1973 850 1100
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Problem Solving Tools or 7 Basic Quality Tools are thetechniques used for continuous improvement…
ProblemSolvingTools
Root Cause Analysis
Histogram
ParetoDiagram
ScatterDiagram
Stratification
Check Sheets
Graphs &ControlCharts
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About Stratification…
What is it?
• A method for grouping data by common characteristics enabling better understanding oftrends by focusing only on relevant data.
Why use it?
• To dismantle the entire data set & break it into smaller related groups.
Purpose
• Focuses attention on a vital/significant subgroup
• Enables a more precise analysis
• Helps to verify root cause
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Examples for Stratification…
Factors Data can be grouped
WHODepartmentIndividual
WHAT Type of DefectReason for Defect
WHENMonth, Quarter, Days
Shift-wise
WHERE
Area
Section
WHICHProduct
Equipment
Examples
Complaints of SystemMalfunctioning
•Branch-wise•Machine-wise•Package-wise•Lot-wise
Accidents
•Shop-wise•Shift-wise• Age-wise
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Steps to stratify the data using pivot table…
• Select ―Microsoft Excel list ordatabase‖
• Go to ―Insert‖.
• Click on ―Pivot Table‖.
• Select the Data range.
• Click on ―OK‖.
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Steps to stratify the data using pivot table… Now you can customize the layout of the pivot tabledepending on which parameters you want to analysis…
• Drag those parameters on which you
want to stratify the data on the
―Row‖ / ―Column‖ of the pivottable.
• By dragging these parameters in the
―Data‖ space, you can get the count /
sum of data points as you desire.
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1 June 2013
Solving problems means identifying the root causes of a problem and thendeveloping and implementing appropriate countermeasures that are designedto eliminate the root causes and prevent their recurrence.
Important
• Root causes are to be distinguished from causal factors.
• Causal factors are those factors that contribute to the occurrence of aproblem, but are not necessarily the initiating cause of a problem—the rootcause.
• Causal factors and chains need to be analyzed further to determine their rootcauses.
A robust problem-solving method must be adept at not only identifying aproblem‘s causal factors, but equally adept at uncovering the root causes thatunderpins the causal factors.
Problem solving basics
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