problem solving basic 7 qc tools
DESCRIPTION
Basic 7 QC Problem solving toolsTRANSCRIPT
Problem Solving – Basic 7QC Tools
2
What are 7 QC Tools ?
QC tools are the means for Colleting data , analyzing data , identifying root causes and measuring the results.
Tools are used to identify , analyze and resolve Problems
Problem Solving Tools
1 Why -Why Analysis ( For Corrective action)2 What If Analysis ( For Potential Problems)
1. Simple Tools for Problem Analysis
2 Simple 7 QC Tools (Statistical Tools)• Check SheetsCheck Sheets• Pareto AnalysisPareto Analysis• Graph / FlowchartsGraph / Flowcharts• Cause & Effect DiagramCause & Effect Diagram• HistogramsHistograms• Scatter PlotsScatter Plots• Control ChartsControl Charts
Problem Solving Tools
What is a “Problem “?“Problem is an undesirable event” or ..
Any Gap between what is expected and what is obtained , can be called as a Problem, and any effort to reduce this gap can be called as
“Problem Solving”
Expected
Obtained Obtained
(Gap ?) A Problem! (Gap ?) A Problem!
Ideal situation / Objective
Present Level
What is PROBLEM ?
Example : Objective of machining Throttle body Boring operation
– Bore Dia 40 + 0.025 mm
- Actual – 39.992 mm
Objective – 40+0.025mm
Actual = 39.992 mm
Gap = 0.008 mm
Problem Solving Tools
Four types of Problems
Problem Solving Tools
Library of Problem Solving Tools Why - Why analysis - An Example
Purpose : It is the simple tool used by the team /observer to find out the cause of the problem/Accident/ Breakdown at the Workplace.Many times, the root cause of the problem can be identified by asking Why 5 times and the repetition of such problems can be prevented by taking countermeasure immediately.
Water Dripping in Substation 1
WHY ?
WHY ?
WHY ?
WHY ?
Water accumulated at the roof
Outlet drain chocked
Atmospheric dust & dirt
Periodic cleaning of drain not done
Action
Proper scheduled procedure for roof cleaning is to be prepared
Problem Solving Tools
Library of Problem Solving Tools Why - Why analysis - An Example
Problem Solving Tools
Library of Problem Solving Tools What-If Analysis
Purpose : It is the simple Pro active tool used by the team / observer, to identify problems before hand and take appropriate counter measures to prevent such problems .
Problem Solving Tools
Library of Problem Solving Tools What-If Analysis - An Example
SL. What If Results Countermeasures
Area : Equipment :CompressorTeam :
1. There is no Water in the Radiator of an Automobile ? And it is not noticed.
The Engine heats up and Piston mayget seized.
• Inspect the Temperature of outlet water . • Provide the temp. Indictor for the driver
What are the Basic Seven QC Tools ?
Check Sheets Pareto AnalysisGraph / FlowchartsCause & Effect DiagramHistogramsScatter PlotsControl Charts
What is Check sheet :
A Check sheet is a paper form on which items to be checked have been printed.
Purpose : To collect the data
What is Check sheet :
• Shown a check sheet of molded ComponentDefective Item check sheet
Part Name: Manifold B Date: 29/01/2011
Part No. E178012 Lot No. Y129
Total No. inspected 780 Inspector Name Ahbay
Sr No. Check Point Standard Defect (Nos.)
1 Flow Mark Not allowed 10
2 Crack Not allowed 4
3 Flashes Not allowed 9
4 Shrinkage Not allowed 17
Total Defects 40
Total Rejects 30
What is Check sheet :
• Shown a check sheet of molded ComponentDefective Item check sheet
Part Name: Manifold B Date: 29/01/2011
Part No. E178012 Lot No. Y129
Total No. inspected 780 Inspector Name Ahbay
Sr No. Check Point Standard Defect (Nos.)
1 Flow Mark Not allowed 10
2 Crack Not allowed 4
3 Flashes Not allowed 9
4 Shrinkage Not allowed 17
Total Defects 40
Total Rejects 30
What is Check sheet :• Another example
Daily Assy . Check SheetPart Name: Throttle Body assy. Date: 29/01/2011
Part No. 13400 M 67LA0 Lot No. C1114
Total No. inspected 240 Checking Freq. 1 / 240
Sr No. Check Point Standard Observation
1 Air leak 6.4 Kpa max 0.2
2 Water leak 68 Pa max 18
3 TPS output 800±15 mV 802
4 ID setting 61.3~72.5 Kpa 66.4
Checked by Yoginder
Purpose of Check Sheet
Variation in the Quality Characteristics of a ProcessApplicable for Histogram , Control Chart.
Difference between Groups / MachinesApplicable for Pareto Diagram.
Relation between two characteristicsApplicable for Scatter Diagram
PARETO DIAGRAM
Pareto is combination of Column & Line graph.
Purpose : To prioritize major contributing problem from others which is less contributing.
PARETO DIAGRAM
Invented by Vilfredo Pareto (1848-1923) Italian economist.
- 20 % of the population has 80 % of wealth
Juran – 20 % of quality problem caused 80 % of the dollar loss.
PRINCIPLE OF PARETO
80-20 Principle
80 % improvement can be achieved by working on 20 % of the causes.
PARETO DIAGRAMMonthly Rejection Data
S. No. Type of DefectNo. of defects
Cumulative of Overall
total
% of overall total
Cumulative %
1 Axial Torque 150 150 50 50
2 Air Leak 90 240 30 80
3 Left side Clearance 30 270 10 90
4 Th. Body tight 20 290 7 97
5 Blow hole 7 297 2 99
6 Dent 3 300 1 100
Total 300 - 100 -
PARETO DIAGRAM
150
90
3020
7 3
50
80
9097
99 100
0
10
20
30
40
50
60
70
80
90
100
0
50
100
150
200
250
300
Axial Torque Air Leak Left side Clearance
Th. Body tight
Blow hole Dent
PARETO DIAGRAM
80 % of rejection can be reduced on taking action on Axial torque & Air Leak.
What is defective : A unit that contains at least one defect.
What is defect :-Output of a process that does not meet a
defined specification.
FLOW CHARTS / GRAPHS
Flow Charts:A Tool that graphically represents the steps of
a process
Purpose :- In which process that Problem occurred
GRAPHS
It is pictorial view of data presentationPurpose : Instance Information
Type of Graph.Line GraphBar GraphPie Chart Radar Chart
LINE GRAPH
It is used to monitor the trend of process.
BAR GRAPH
It is used to compare with other.
PIE CHART
It is used to show share/contribution
RADAR CHARTIt is used to total sharp image as a composite
graph
CAUSE & EFFECT DIAGRAMIt shows the relationship between problem &
its possible cause
Developed by Kaoru Ishikawa (1953)
Also known as …o Fishbone Diagramo Ishikawa Diagram
METHODOLOGY
Step 1: Identify All Possible causes
Step 2: Identify Potentional / Suspect causes
Step 3: Validate the all Potential cause
Step 4: Root Cause
CAUSE & EFFECT
Cause are divided into four major Cause are divided into four major sources:sources:
MANMAN MATERIALMATERIAL METHODMETHOD MACHINEMACHINE
EFFECT- OUTCOME OF CAUSESEFFECT- OUTCOME OF CAUSES
STEP 1: IDENTIFY PROBABLE CAUSES
MAN MATERIAL
METHOD MACHINE
EFFECT
STEP 2: IDETIFY THE POTENETIONAL CAUSE
MAN MATERIAL
METHOD MACHINE
EFFECT
STEP 3 : VADILATE THE CAUSE
Sr. No Potentional Cause Validation Conclusion
STEP 4 : ROOT CAUSE
Why-Why Analysis
Why 1 Why bracket welding brokenBecause it was not welded
properly
Why 2 Why not welded properly Because welding jig was loose
Why 3 Why welding jig was loose Because Welding jig worn
Why 4 Why Welding jig worn Welding Jig life not defined.
Why 5
STEP 4 : ROOT CAUSE
Why-Why analysis of two type:Why-Why analysis of two type:
For Occurrence :For Occurrence : Why defect Why defect generated in processgenerated in process
For Outflow: For Outflow: Why defect pass to Why defect pass to customer.customer.
Histograms
PLOTTING THE SHAPE OF A DISTRIBUTION
COMPARING THE DISTRIBUTION WITH SPECIFICATIONS
USEFUL FOR QUALITY, COST AND DELIVERY IMPROVEMENT
USEFUL FOR PROCESS CONTROL
HistogramsHistogram
LSLUSL
Diameter
Frequency
Constructing a HistogramUse range to estimate beginning and end Calculate the width of each column by
dividing the range by the number of columns
Range
# of Columns
= Width
SCATTER DIAGRAM
A graphical technique to shows the A graphical technique to shows the dependency of two variables / dependency of two variables / factorfactor
For example : what extent surface For example : what extent surface finish of machined part varied by finish of machined part varied by changing the speed of lathe.changing the speed of lathe.
SCATTER DIAGRAM
Speed of lathe (RPM)
Surface finish (Ra)
700 3.3
800 3.0
900 2.7
1000 2.4
1100 2.1
1200 1.8
1300 1.5
1400 1.2
1500 0.9
Data collect for speed & Surface Data collect for speed & Surface finishfinish
Cause Effect
SCATTER DIAGRAM
Output/ Effect
Causes
RULE FOR SCATTER DIAGRAMThere should be minimum 30 There should be minimum 30
readings readings
N=30 to check dependency.N=30 to check dependency.
Positive Scatter Diagram:Positive Scatter Diagram:
Negative Scatter Diagram:Negative Scatter Diagram:
SCATTER DIAGRAM
Speed of car Km/Hr
MileageKm/Ltr
30 15
35 16
40 17
45 18
50 19
55 20
60 21
65 20
70 19
75 18
80 17
85 16
90 15
95 14
SCATTER DIAGRAM
CONTROL CHARTS
Control charts is used to detect the Control charts is used to detect the abnormal trends with the help of abnormal trends with the help of line graphs.line graphs.
Invented by Dr. W.A. ShewhartInvented by Dr. W.A. Shewhart
CONTROL CHARTS
Variable Chart :- Variable Chart :-
a)a)Average & Range ChartAverage & Range Chart
b)b)Median & Range ChartMedian & Range Chart
Attribute Chart :Attribute Chart :
a)a)P & np Chart P & np Chart
b)b)c & u Chart c & u Chart
CONTROL CHARTS
X bar Chart : It shows the centering X bar Chart : It shows the centering of the process.of the process.
R bar Chart : It shows the variation R bar Chart : It shows the variation between the subgroup size.between the subgroup size.
CONTROL CHARTS
Diameter of Shaft :- 23±0.2Diameter of Shaft :- 23±0.2
No. of Subgroup (N)= 10No. of Subgroup (N)= 10
Subgroup size = 5Subgroup size = 5
CONTROL CHARTS
X =(X1+X2+X3+X4+…….+X10)/N X =(X1+X2+X3+X4+…….+X10)/N
R=(R1+R2+R3+R4+……..+R10)/NR=(R1+R2+R3+R4+……..+R10)/N
Control Limit – XbarControl Limit – Xbar
UCLx= X + A2 R = UCLx= X + A2 R =
LCLx= X - A2 RLCLx= X - A2 R
Control Limit – R barControl Limit – R bar
UCLr= D4 RUCLr= D4 R
LCLr= D3 RLCLr= D3 R
Where D4,D3 & A2 are constantWhere D4,D3 & A2 are constant
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Process control ( Standardization )
Evaluation of result
Implementation
Develop Improvement method ( Solution )
Detecting causes of problem
Record of facts
Defining the problem
Identification of problem
Control Chart
Scatter Diagram
Histogram
Cause & Effect Diagram
Pareto Diagram
Check sheet
Graphs / Flow Charts
Application of QC tools in Problem Solving
Relation :-
Strong Normal
Thank You !!!