wcm - six sigma
DESCRIPTION
six sigmaTRANSCRIPT
Mayuresh Unde
4th Feb, 2011
Six Sigma
What is Six Sigma?
• A methodology to improve a business process by constantly reviewing, updating and re-tuning the existing process.
• Six Sigma improves the process performance, decreases variation and maintains consistent quality of the process output. This leads to defect reduction and improvement in profits, employee morale, product quality and finally customer satisfaction.
• Six Sigma relies heavily on statistical techniques to reduce defects and measure quality.
Business DefinitionA break through strategy to significantly improve customer
satisfaction and shareholder value by reducing variability & improving quality in every aspect of business.
Technical DefinitionA statistical term signifying 3.4 defects per million
opportunities.
Six Sigma
• The era ‘1986 to 1990’ is referred to as the firstgeneration of Six Sigma.
• Pioneered at Motorola by an Engineer – Bill Smith• Statistical approach• Measured Defects Per Million Opportunities (DPMO)• Focused on:
– Elimination of defects– Improving product and service quality– Reducing cost– Continuous process improvement
Consider 99% Quality Level
5000 incorrect surgical operations per week!
200,000 wrong drug prescriptions per year!
2 crash landings at most major airports each day!
20,000 lost articles of mail per hour!
Cost of Poor Quality (COPQ)
The costs of poor quality are those costs associated with providing poor quality products or services.
There are four categories of costs:1. Internal Failure Cost – costs which occur prior to delivery or shipment of a
product to the customer
2. External Failure cost – costs which occur after shipment of a product to the customer
3. Appraisal cost – costs associated with measuring, evaluating or auditing products or services to ensure conformance to quality standards
4. Prevention cost – cost of activities specially designed to prevent poor quality in products or services
Statistical background
Target = m
Some Key measure
+/ - 3 s
Statistical background
Target = m
‘Control’ limits
+/ - 3 sLSL USL
Statistical background
Required Tolerance
Target = m
+/ - 3 s
+/ - 6 s
LSL USL
Statistical background
Tolerance
Target = m
Six-Sigma
+/ - 3 s
+/ - 6 s
LSL USL
ppm1350
ppm1350
Statistical background
Tolerance
Target = m
+/ - 3 s
+/ - 6 s
LSL USL
ppm0.001
ppm1350
ppm1350
ppm0.001
Statistical background
Tolerance
Target = m
LSL
0 ppm ppm3.4
1.5sUSL
ppm3.4ppm
66810
m
+/ - 6s
Statistical background
Tolerance
• Six-Sigma allows for un-foreseen ‘problems’ and longer term issues when calculating failure error or re-work rates
• Allows for a process ‘shift’
Six Sigma & % accuracy
Defects per Million % AccuracyOpportunities (DPMO)
One Sigma 691,500 30.85%Two Sigma 308,500 69.15%Three Sigma 66,810 93.32%Four Sigma 6,210 99.38%Five Sigma 233 99.977%Six Sigma 3.4 99.9997%Seven Sigma 0.020 99.999998%
Input – process - Output
Input Process Output
X (KPIVs) Y (KPOVs)
Y=f(X)
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Define
Measure
Analyse
Control
Improve
Six Sigma Methodology (DMAIC)
• Motorola developed a five phase approach to the Six Sigma Process called DMAIC which is a continuous process as the diagram shows until the highest level in the Six Sigma is achieved, i.e., 3.4 defects per million.
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DMAIC Steps - 1. Define
• Identify projects that are measurable• Understand the overall business process
– SIPOC diagram
• Understand customer requirement – Voice of the customer (VOC), Kano Model
• Convert customer requirement into CTQ (Critical to Quality)– Quality Function Deployment: Also called as ‘House of Quality’, is a
process to ensure that customer wants and needs are translated into technical characteristics
• Develop team charter & team– Goal Statement
1. Define 2. Measure 3. Analyze 4. Improve 5. Control
SIPOC Diagram
VOCWhat does the Customer Want?
Voice Of the Customer (VOC)
Focus GroupsInterviews Surveys Organizational Metrics
Kano Model
Quality Function Deployment
QFD is a graphic method of expressing relationships between customer wants and design features
Six Sigma Team
Six Sigma Team
• Own vision, direction,integration, results
• Lead change
• Project owner• Implement solutions• Black Belt managers
• Full time• Train and coach
Black and Green Belts• Statistical problem solving experts
• Devote 50% - 100% of time to Black Belt activities• Facilitate and practice problem solving• Train and coach Green Belts and project teams
• Part-time• Help Black Belts
Master BlackBelts
Black Belts
Green BeltsProject Champions
Executive Leadership
• Perform data collection & analysis
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DMAIC Steps 2. Measure
• Overall Data Collection– Checklists, Sampling etc – Define performance standards– Evaluate project baseline & Measure current level of quality
into Sigma. It precisely pinpoints the area causing problems.
• Identify all potential causes for such problems. – Cause & Effect (Fishbone)– Problem areas needing improvement (Pareto analysis), Failure
Mode Effect Analysis (FMEA),
• Measurement System Analysis– R&R Study
5.0Control
2. Measure1. Define 3. Analyze 4. Improve 5. Control
Pareto Analysis & FMEA
Pareto charts are specialized form of column graphs. They are used to prioritize problems so that major problems (or opportunities) can be identified. Pareto principle states that a few problem categories (approx 20%) will present the most opportunity for improvement (approx 80%)
FMEA is a disciplined approach to evaluate designs to ensure that all possible failure modes have been taken into consideration from a probability, severity and detection standpoint
FMEA ratings
No method for
detectionAlways occurs
Performance,
quality, cost or
safety impacts
High (10)
Some methods, but
cannot always be
detected
Occurs less
frequently
Performance,
quality, and cost
impacts
Medium (5)
Can always be
detectedOccurs very rarelyNo impactLow (1)
DetectionOccurrenceSeverity
Compute Risk priority number (RPN) based on these factors
Measurement System Analysis
R & R Study:1. Reproducibility (Reliability) : The ‘Reliability’ of a gauge system is an ability to
reproduce measurements. The reproducibility of a single gauge is checked by comparing the results of different operators taken at different times.
2. Repeatability (Precision): It is the ability to repeat the same measurement by the same operator at or near the same time.
Analysis of Variance Method (ANOVA) is the most accurate method for quantifying repeatability and reproducibility. In addition, the ANOVA method allows the variability of the interaction between the appraisers and the parts to be determined
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• Establish process capability
• Analyze data to find the root cause
3.0 Analyze
Statistical Tools for analysis
Multi-variate analysis & regression testing
Statistical Tests – ‘t’, ‘Z’, ‘Chi-square’,
Hypothesis testing
Estimators – Point estimation & Interval estimation
ANOVA
3. Analyse1. Define 2. Measure 4. Improve 5. Control
DMAIC Steps 3. Analyze
Tools for analysis
Fishbone Analysis
Data Analysis using graphical tools –Scatter diagrams, Least Mean square method etc
Fishbone Analysis – Ishikawa Diagram
Roast
Cool
Grind
Pack
Coffeebeans
Sealed coffee
Moisture content
MaterialMachineMan
Method Measure-ment
MotherNature
Amount of
added water
Roasting
machines
Batch
size
Reliability
of Quadra Beam
equipment
Weather
conditions
Moisture%
Training of
worker
Scatter Diagrams
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DMAIC Steps 4. Improve
• Screen potential causes
• Discover variable relationships among causes and effects
• Establish operating tolerances
• Pursue a method to resolve and ultimately eliminate problems. It is also a phase to explore the solution how to change, fix and modify the process.
• Carryout a trial run for a planned period of time to ensure the revisions and improvements implemented in the process result in achieving the targeted values.
– Design of Experiments (DoE)
4. Improve1. Define 2. Measure 3. Analyse 5. Control
Design of Experiments (DoE)
One factor (X)
low high
X1
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2
Two factors (X’s)
low
high
high
X2
X1
2
high
Three factors (X’s)
low highX1
X3
X2
2
3
DoE is a methodology of varying a number of input factors simultaneously, such that their individual and combined effects on the output can be identified.
DoE Example – Full Factorial Design
# T P C Yield
1 - - - 55
2 + - - 77
3 - + - 47
4 + + - 73
5 - - + 56
6 + - + 80
7 - + + 51
8 + + + 73
T = Temperature(120 & 150), P = Pressure(10 & 14 bar), C = Concentration(10 & 12N), Y= % Yield
# T P C TxP PxC TxC TPC Yield
1 - - - + + + - 55
2 + - - - + - + 77
3 - + - - - + + 47
4 - - + + - - - 73
5 + + - + - - + 56
6 - + + - - + - 80
7 + - + - + - - 51
8 + + + + + + + 73
Temperature effect = ((77+73+80+73) – (55+47+56+51)) / 4 = 23.5Pressure effect = ((47+73+51+73) – (55+77+56+80)) / 4 = - 6Concentration effect = ((56+80+51+73) – (55+77+47+73)) /4 = 2Similarly, TxP Interaction = ((55+73+56+73) – (77+47+80+51)) / 4 = 0.5
Result: High T, Low P and High C, while interactions are marginal and hence can be neglected
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• Monitor the improved process continuously to ensure long term sustainability of the new developments. – Control Charts / SPC analysis
• Monitor the Xs which in turn will monitor the Y• Create a response plan for dealing with problems that
may arise• Share the lessons learnt• Document the results and accomplishments of all the
improvement activities for future reference.
5. Control1. Define 2. Measure 3. Analyse 4. Improve
DMAIC Steps 5. Control
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Six Sigma – Case study
• A dabbawala is a person in the Indian city of Mumbai whose job is to carry and deliver freshly made food from home in lunch boxes to office workers.
• 5000+ Dabbawalas pick up 175,000 lunches from homes and deliver to their customers everyday.
• Only one mistake is made in every 6 million deliveries.
• Accuracy rating is 99.999999. More than Six Sigma.
Benefits of Six Sigma
Focus on customers.Improved customer loyalty.Reduced cycle time.Less waste.Data based decisions.Time management.Sustained gains and improvements.Systematic problem solving.Employee motivation.Data analysis before decision making.Faster to market.Improved customer relationsAssure strategic planningReductions of incidents.Measure value according to the customerBetter safety performanceUnderstanding of processes
Design and redesign products/services.Knowledge of competition, competitors Develop leadership skills.Breakdown barriers between departments and functions.Integration of products, services and distribution.Use of standard operating procedures.Better decision making.Improving project management skills.Sustained improvements.Alignment with strategy vision, and values.Increased margins.Greater market share.Lower costs to provide goods and services.Fewer customer complaints.