Post on 22-Jan-2018
7 QC TOOLSPRESENTED BY: Anand K Tiwari
The 7 Basic Quality Tools
Ishikawa believed that 90% of all quality problems could be solved through the use of the 7 tools listed below:
Cause and Effect (Ishikawa) DiagramsCheck SheetsHistrogramPareto diagramsFlowchartsScatter DiagramsControl Charts
What are the Basic Seven Q.C. Tools?
Cause and Effect (Ishikawa) Diagrams
-Brain StormingCheck SheetsFrequency DiagramsPareto diagramsFlowchartsScatter DiagramsControl Charts
7- QC ToolS (BASIC)
BRAIN - STORMING
Brainstorming Ideas generation
Time the session Count of ideas generated Named and anonymous ideas Each idea depicted as node of a tree Simple session
Free generation of ideas Structured session
Predefined set of questions defined as a template Generate ideas under each question
Brain Storming
Grouping Print labels in background to involve participants in
grouping of ideas
Incubation Print idea labels Print list of ideas
Clarif ication Add description to clarify the idea
Brain Storming
Preliminary Selection Mark an idea/group/sub-group as selected
depicted by a check mark (May be carried out while grouping the ideas)
Filtering and Prioritization Criteria definition Multi voting Multi criteria voting and selection Decision grid Group weightage analysis thru ideas
ranking Drivers and Barriers analysis and Final
selection of ideas
Brain Storming
FREQUENCY DIAGRAMS(Histrogram)
7- QC ToolS (BASIC)
Frequency Diagrams Process centering, spread and shape
Measurements of 50 items from process XYZ147 179 185 125 210
131 137 141 142 166
198 142 205 150 141
190 161 157 165 155
165 155 169 158 150
170 125 177 108 193
178 181 155 186 145
157 135 148 171 124
168 141 151 162 150
145 177 154 137 160
Frequency DiagramsProcess centering, spread and shape
TALLY CHARTRANGE TALLY NUMBER
100-109 | 1
110-119 0
120-129 | | | 3
130-139 | | | | 4
140-149 | | | | | | | | | 9
150-159 | | | | | | | | | | | 11
160-169 | | | | | | | | 8
170-179 | | | | | | 6
180-189 | | | 3
190-199 | | | 3
200-209 | 1
210-219 | 1
TOTAL 50
Frequency DiagramsProcess centering, spread and shape
0
2
4
6
8
10
12
100 -109
110 -119
120 -129
130 -139
140 -149
150 -159
160 -169
170 -179
180 -189
190 -199
200 -209
210 -219
Frequency
Frequency Diagrams Process centering, spread and shape
Frequency Diagram with tolerances
0
2
4
6
8
10
12
100 -109
110 -119
120 -129
130 -139
140 -149
150 -159
160 -169
170 -179
180 -189
190 -199
200 -209
210 -219
Frequency
Lo
we
r T
ole
ran
ce (
12
5)
Up
pe
r T
ole
ran
ce (
18
5)
Sp
ec.
S
pe
c.
(15
5)
(15
5)
Frequency Diagrams Process centering, spread and shape
Normal Distribution
Bi-Modal Distribution Multi-Modal Distribution
Positively Skewed Negatively Skewed
CAUSE & EFEECT
DIAGRAM
7- QC ToolS (BASIC)
Cause and Effect Analysis Ishikawa fish bone diagramming
Easy to draw like on paper
5 Why’s technique Why?… Why?…. Why?…. Why?…….. Why?
Identif ication of Root causes Mark a cause as a root cause Assign a priority number
Cause and Effect Diagrams Cause and Effect Diagrams Find and cure causes NOT symptomsFind and cure causes NOT symptoms
Possible CausesPossible CausesPROBLEMPROBLEM(EFFECT)(EFFECT)
Area AArea A Area BArea B
Area DArea DArea CArea C
11
22
3366
55
4411
22
3366
55
44
11
22
3366
55
44
11
22
3366
55
44
Cause and Effect Diagrams Cause and Effect Diagrams Find and cure causes NOT symptomsFind and cure causes NOT symptoms
Bad SolderJoints
Machines Manpower
MaterialsMethods
Solder Gun
Size
Heat sink
Power Source
Skill
Training
Physical limits
Terminals
Stripping
TechniqueManual Flux
Solder
Wire Gauge
Cause and Effect Diagrams Cause and Effect Diagrams Find and cure causes NOT symptomsFind and cure causes NOT symptoms
Bad SolderJoints
Machines Manpower
MaterialsMethods
Solder Gun
Size
Heat sink
Power Source
Skill
Training
Physical limits
Terminals
Stripping
TechniqueManual Flux
Solder
Wire Gauge
Cause and Effect Diagrams Cause and Effect Diagrams Find and cure causes NOT symptomsFind and cure causes NOT symptoms
CHECK SHEETS
7- QC ToolS (BASIC)
contd…
Check Sheets and data analysis Facil i ty to design a Check sheet
Qualitative data Quantitative data with summation, averages etc.
Data Collection faci l i ty Data Analysis
Pareto chart Scatter diagrams Stratification Bar graph Line graph Pie chart
Printing of check sheet(s) and collected data
Check Sheets Counting and accumulating data
Products FaultsFault 1 Fault 2 Fault 3 Total
A | | | | | | 6B | | 2C | | | 3D | | | | | 5
Total 8 3 5 16
Check Sheets Counting and accumulating data
Process Name: Gauging/ Final Product Name: Carrier
TOTAL3/82/81/831/730/7 Defective part
61811151413TOTAL
7| | || | ||Other
2||Wire Pitted
9|| || | | ||Hole U/Size
14| | | || | || || | | |Dent, Scratch
8|| | | || |Welding Spatters
21| | | || | || | | | || | || | | |C.D.variation
Line Name: Carrier LineProduct Number: 123456
Check Sheets Counting and accumulating data
PARETO DIAGRAM
7- QC ToolS (BASIC)
Pareto Diagrams Focus on key problems
Fault No.A. DRY JOINTB. MISSED COMPONENTC. REVERSED COMPONENTD. ARCINGE. OPEN CIRCUITF. OTHER
258413
TOTAL 23
Fault No.C. REVERSED COMPONENT B. MISSED COMPONENTD. ARCINGF. OTHERA. DRY JOINTE. OPEN CIRCUIT
854321
TOTAL 23
Pareto Diagrams Focus on key problems
88
REVERSEDREVERSEDCOMPONENTCOMPONENT
55
MISSED MISSED COMPONENTCOMPONENT
44
ARCINGARCING
33
OTHEROTHER22
DRY JOINTDRY JOINT 11OPEN CIRCUITOPEN CIRCUIT
BBCC DD FF AA EE
Pareto Diagrams Focus on key problems
Fault No. COST TOTAL COST
C. REVERSED COMPONENT B. MISSED COMPONENTD. ARCINGF. OTHERA. DRY JOINTE. OPEN CIRCUIT
854321
225146
161020386
TOTAL 23 - 63
Pareto Diagrams Focus on key problems
Fault No. COST TOTAL COST
D. ARCING C. REVERSED COMPONENT B. MISSED COMPONENT A. DRY JOINTE. OPEN CIRCUITF. OTHER
485213
522461
201610863
TOTAL 23 - 63
Pareto Diagrams Focus on key problems
Rs. 20
ARCING
Rs.16
REVERSEDCOMPONENT
Rs.10
MISSED COMPONENT
Rs.8
DRY JOINT
Rs. 6
OPEN CIRCUITRs.3OTHER
CD B A E F
Check Sheets Counting and accumulating data
FLOW CHARTS
7- QC ToolS (BASIC)
Flow chart ing Drawing of a Process-chart with all standard step
symbols Facility to define a Template Form for capturing
measurement data about each step Summary report of the Process-chart Facility to draw a Process map Facility of dragging the steps of a Process-chart to a
Brainstorming session for analysis of each step under a predefined template of questions
Flowcharts Picturing the process
TerminatorUsed to Start/Stop flowchart
DataUsed to indicate datain or out of the process
ActivityUsed to show a task oractivity performed in the process.
DecisionShows the points in the process where yes/noquestions are asked
DelayUsed to indicate delaysor stock points in the process.
ConnectorUsed to link differentPoints in the flowchart.A
Flowcharts Picturing the process
StartStartDoes
patient havean app’t
?
Patient arrives
Y
N
Waiting room
Appoint’t slip
Consultation
A AMake an Appointm’t
Y
N
Waitto see doctor
?
Need a follow-up
app’t?
Y
N
Need to pick up
drugs?
Fill prescrip’nat pharmacy
Patient’snotes
Patient leaves
Stop
Y
NAppoint’t
diary
Flowcharts Picturing the process
SCATTER DIAGRAM
7- QC ToolS (BASIC)
Car Age (in years)
Price(in £’s)
1 2 4000
2 4 25003 1 5000
4 5 1250. . .. . .. . .
44 7 10000
10002000300040005000600070008000900010000
0 5 10
Scatter Diagrams Measuring relationships between variables
3.5
4
4.5
5
150 400 650
3.5
4
4.5
5
150 400 650
3.5
4
4.5
5
150 400 6503.5
4
4.5
5
150 400 650
3.5
4
4.5
5
150 400 650
PositivPositive Correlation
Positive Correlation?
Negative Correlation
Negative Correlation?
No CorrelationAn increasAn increase in y may dependupon an increase in x.E.g.
If X is increased, y may also increase.
If X is increased, y maydecrease.
There is no demonstrated connection between x and y.
An decrease in y may dependupon an increase in x.
Scatter Diagrams Measuring relationships between variables
CONTROL CHARTS
7- QC ToolS (BASIC)
Control Charts Recognising sources of variation
0
5
10
15
20
25
30
35
40
0 1 2 3 4 5 6 7 8 9 10
Lower Control Limit (LCL)
Upper Control Limit (UCL)
Average(Xbar)
Control Charts Recognising sources of variation
Variables dataTemperatureLengthCost
Attributes dataNumber of porous castings in a sample (defective parts)Number of cavities in a porous casting (defects)Shipping errors
Choose appropriate control chart
Attribute data:Counted and
plotted as discrete events
Variable data:Measured and plotted on a
continuous scale
Control Charts Recognising sources of variation
Attribute Data
Defect Data Defective Data
Defect = failure to meet one of the acceptance criteria.
Defective = An entire unit fails to meet acceptance criteria.
(Defectives may have multiple defects)
Constantsample size,
usually > 5 c
c Chart
Variablesample size,
u Chart
Constantsample size,usually ≥ 50
Variablesample size,usually ≥ 50
np Chart p Chart
Fraction defectiveNumber defectiveNumber of defects Number of defectsper unit
Control Charts Recognising sources of variation
Variable Data
Sample size= 1
X and Rm
Sample sizeis small, 2~9
Sample size islarge
usually ≥ 10
and RX and sX
Individuals and moving range
Average and standard deviation
Average and Range
Control Charts Recognising sources of variation
Control Charts Recognising sources of variation
Point above or below control limit.Causes: “special cause”,misread, data entry, etc.
Run 7 points increasingor decreasingCauses: maintenance, wear,environment, etc
Run of 7 points aboveor below the meanCauses:changed dist’n,new method, etc.
Erratic readingsCauses: over adjustment,measuring equipment not capable, etc
Shift in readingsCauses: change in mat’l,change in operator, etc
Cyclic readingsCauses: work pattern,Environment, etc.
GroupingFlier Shift
Trend Erratic Cycle
• Cause and Effect (Ishikawa) DiagramsCause and Effect (Ishikawa) Diagrams-Brain Storming-Brain Storming
• Check SheetsCheck Sheets• Frequency DiagramsFrequency Diagrams• Pareto diagramsPareto diagrams• FlowchartsFlowcharts• Scatter DiagramsScatter Diagrams• Control ChartsControl Charts
7- QC ToolS (BASIC)
Cause and Effect Diagram
Enables a team to focus on the content of a problem, not on the history of the problem or differing personal interests of team membersCreates a snapshot of collective knowledge and consensus of a team; builds support for solutionsFocuses the team on causes, not symptoms
Effect
Cause
Check Sheet
Creates easy-to-understand data Builds, with each observation, a clearer picture of the factsForces agreement on the definition of each condition or event of interestMakes patterns in the data become obvious quickly xx
xxxxxx x
Histogram
Displays large amounts of data that are difficult to interpret in tabular formShows centering, variation, and shapeIllustrates the underlying distribution of the dataProvides useful information for predicting future performanceHelps to answer the question “Is the process capable of meeting requirements?
Pareto Diagram
Helps a team focus on causes that have the greatest impactDisplays the relative importance of problems in a simple visual formatHelps prevent “shifting the problem” where the solution removes some causes but worsens others
Flowcharts
Shows unexpected complexity, problem areas, redundancy, unnecessary loops, and where simplification may be possibleCompares and contrasts actual versus ideal flow of a processAllows a team to reach agreement on process steps and identify activities that may impact performanceServes as a training tool
Control Chart
Focuses attention on detecting and monitoring process variation over timeDistinguishes special from common causes of variationServes as a tool for on-going controlProvides a common language for discussion process performance
* * * * *
* *
Run Chart
Monitors performance of one or more processes over time to detect trends, shifts, or cyclesAllows a team to compare performance before and after implementation of a solution to measure its impactFocuses attention on truly vital changes in the process
* * * * *
* *
Scatter Diagram
Supplies the data to confirm a hypothesis that two variables are relatedProvides both a visual and statistical means to test the strength of a relationshipProvides a good follow-up to cause and effect diagrams
* * ** * *
THANKS