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Six Sigma Black Belt
Cert. Prep. Course:Design for Six Sigma (DFSS)Design for Six Sigma (DFSS)Design for Six Sigma (DFSS)Design for Six Sigma (DFSS)
Frameworks andFrameworks andFrameworks andFrameworks and
MethodologiesMethodologiesMethodologiesMethodologiesModule IX
©2009 ASQ 2
Agenda
This module consists of four lessons:
1. Common DFSS methodologies2. Design for X (DFX)
3. Robust design and process4. Special design tools
©2009 ASQ 3
Lesson 1 – Common DFSSMethodologies
Identify and describe these methodologies. (Understand)
1. DMADV (define, measure, analyze, design, and validate)2. DMADOV (define, measure, analyze, design, optimize,
and validate)
IX.A Common DFSS methodologies
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©2009 ASQ 4
Six Sigma vs. DFSS
• DFSS is a proactive, rigorous, systematic method using tools,
training, and measurements for integrating customer requirementsinto the product development process. DFSS strives to preventdefects bytransformingcustomer needs andexpectations to whatcan be produced,whereas the SixSigma DMAICmodel focuses
on eliminatingdefects by reducingoperationalvariability.
©2009 ASQ 5
DFSS
• Quality experts regard 70-80% of quality problems as design-related. Engineers and other process designers have the bestopportunity to improve product quality and save costs.
• The greater the initial investment to eliminate design issues,the lower the life-cycle costs associated with the process.Since process improvement after start-up is more costly, awell-developed DFSS project development plan will help to
ensure success and maximize the return on investment.
©2009 ASQ 6
DMADV
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©2009 ASQ 7
DMADOV
• Define the Project (define goals, identify customers, and
identify customer expectations)• Measure the opportunity (determine customer needs/
specifications and benchmark)
• Analyze the process options to meet customer need.
• Design the process by developing a detailed process and
experiments to prove the design meets customer needs.
• Optimize the process by testing the new process and re-
designing as necessary to meet customer specifications.
• Verify the performance and ability of the process to meet
customer needs and deploy the new process.
©2009 ASQ 8
DFSS Project Teams
DFSS project teams include:• Subject matter experts (SMEs).• Six Sigma Black Belts and Green Belts as team leaders.• Master Black Belts as mentors and trainers.• Project champions as process owners and roadblock
breakers.
©2009 ASQ 9
Progress Check
• How does DMAIC difference from DFSS?
• How does DMADV differ from DMADOV?
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©2009 ASQ 10
Lesson 2 – Design for X (DFX)
Describe design constraints, including design forcost, design for manufacturability and producibility,
design for test, design for maintainability, etc.(Understand)
IX.B. Design for X (DFX)
©2009 ASQ 11
Design for X (DFX)
• Approach for designing products and services that meetcustomer requirements.
• A cross-functional team design activity involvingmanufacturing, distribution, and service organizations.
• DFX strategy reviews design continually to find ways toimprove product.
• Due to its use of cross-functional teams and the natureof continual review, DFX is best used within concurrentengineering (simultaneous engineering) as an approach toimprove new product development where the product andassociated processes develop in parallel.
©2009 ASQ 12
DFX Toolbox
• DFX toolbox containsnumerous techniques foraddressing product andprocess design which varyin importance from industryto industry and from
product to product.
• Design for Cost
– Also called ValueEngineering
– Designers mustconsider price
limitations
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©2009 ASQ 13
DFX Toolbox (continued)
• Design for Manufacturability
– To design products and processes in such away that they result in fewer problems during
manufacturing
– Emphasize robustness rather than idealperformance
– Reduce the probability of mistakes by reducingcomplexity
– Design preventative mechanisms for likely errors- Mistake Proofing or Poka-Yoke
– Reduce the number of parts
– Reduce the number of manufacturing operations
©2009 ASQ 14
DFX Toolbox (continued)
• Design for Assembly
– Simplify the product into fewer parts
– Make the product easy to assemble
– Reduce service, decrease time to market, andreduce repair time
– Sometimes Design for Manufacturability andDesign for Assembly are often combined (DFM/A).
©2009 ASQ 15
DFX Toolbox (continued)
• Design for Producibility
– By influencing design and concurrent engineering, DFP isa key metric of the success of product design
– Identifies the needs of innovative manufacturing
– Ensures proposed process will satisfy design requirement
– Decreases cost and risk
– Reduces concept-to-build cycle times
• Design for Test
– Important during development, production, and use
– Makes access points easily assessable
– Creates built-in test points
– Uses standard connections and interfaces
– Tests with standard equipment
– Develops a build-in self test
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©2009 ASQ 16
DFX Toolbox (continued)
• Design for Maintainability (Serviceability)
– Important to the customer
– Designs easy service
– Makes access points simple, yet secure
– Assures reliability of individual components
– Balances reliability and cost with the product’s intendeduse and life
– Reduces downtime for maintenance
– Reduces the number of maintenance tasks
– When applicable, uses disposable parts instead of partsrequiring repair
– Eliminates or reduces the need for adjustment
– Uses mistake-proof fasteners and connectors
©2009 ASQ 17
DFX Toolbox (continued)
• Design for Safety
– Eliminates potential failure elements that may occur duringoperation
– Emphasizes safety throughout the product life: safe tomanufacture, safe to sell, safe to use, and safe to dispose
• Others
– Design for user-friendliness
– Design for ergonomics
– Design for appearance
– Design for packaging
– Design for features
– Design for time-to-market
– Design for environment
©2009 ASQ 18
Progress Check – True or False
1. DFX is applied after failures are reported by the
customer?
2. Design for Cost is also referred to as ValueEngineering?
3. DFX tools could vary from industry to industry?
4. DFM is never combined with DFA?
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©2009 ASQ 19
Lesson 3 – Robust Design andProcessIX.C. Robust Design and Process
Describe the elements of robust product design,tolerance design, and statistical tolerancing. (Apply)
©2009 ASQ 20
What is Robust Design?
• Robust design is an efficient and systematicmethodology that applies statistical experimentaldesign for improving product and productionprocess design, thus aiming to design a more
reliable product or process.
» Genichi Taguchi
©2009 ASQ 21
What is Robust Design?
• Defining the ideal state of the basic function that is performingperfectly is the key to robust design. To achieve this, Taguchisuggests the following guidelines for robust design:
– Identify the ideal function for the product or process.
– Select quality characteristics that are continuous variables.
– Select characteristics that add quality.
– Quality characteristics should cover all aspects of the idealfunction.
– Quality characteristics should be easy to measure.
• Robust design aims to produce a reliable design by controllingparameters so random noise does not cause failure.
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©2009 ASQ 22
Noise
• The factors that cause variability in product functions are callederror factors or noise. Taguchi goes on to define three types of
noise factors and categorizes them as inner and outer noise asfollows (page 22, Computer-based Robust Engineering Essentials for DFSS by Genichi Taguchi, Rajesh Jugulum and Shin Taguchi,ASQ, 2005 )
– Factors due to environmental conditions – outer noise
– Factors due to deterioration – inner noise
– Factors due to variation among products – inner noise
©2009 ASQ 23
Attempting to Control Noise
• Noise factors are difficult, expensive, or impossible to control.In the past, many engineers approached noise problems byattempting to control the noise factors themselves. Because ofthe expense, Dr. Taguchi suggests designers should only usethis type of control action as a last resort, and he recommendsan experimental approach to seek the design parameters to
minimize the impact of the noise factors on variation.
• Operational definition: a product/process is robust when it is
unaffected by noise factors.
• Remember, the goal of robustness strategies is to achieve agiven target with minimal variation.
©2009 ASQ 24
Attempting to Control Noise(continued)• Lack of robustness is synonymous with excessive
variation, resulting in quality loss.
• Ignoring noise factors during the early design stagescan result in product failures and unanticipated
costs; therefore, addressing noise factors early in
the process through robust design minimizes theseproblems.
See CSSBB HB, pages 419-420 for anon-linear response with input noise.
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©2009 ASQ 25
Tolerance Design
• We will discuss two types of tolerancing:
– Worst Case (conventional) Tolerancing
– Statistical Tolerancing
• Tolerance is a permissible limit of variation in a
parameter’s dimension or value. Dimensions andparameters may vary within certain limits without significantlyaffecting the equipment’s function. Designers specifytolerances with a target and specification limits (upper and
lower) to meet customer requirements.
• The tolerance width or range is the difference betweenthose limits, it is the permissible limit of variation.
©2009 ASQ 26
Tolerancing ExampleAssembly Clearance (Gap)Tolerance .001 - .037
Part1
Part2
Part3
Part4
Envelope
Part5
.001
.001
.001
.001
.001
.001
St Dev
± .00315.019Envelope± .00355
± .00344
± .00333
± .00322± .00311
ToleranceNominalPart
Tolerancesdeveloped usingconventional(worst-case
tolerancing)methods.
Calculations
on next slide.
©2009 ASQ 27
Worst-Case Tolerancing Example
GapMin = EnvelopeMin - ∑ (Parti + Tolerancei)m
i
GapMin = 15.016 - (1+.003, 2+.003, 3+.003, 4+.003, 5+.003) = .001
GapMax = EnvelopeMax - ∑ (Parti - Tolerancei)
GapMax = 15.022 - (1-.003, 2-.003, 3-.003, 4-.003, 5-.003) = .037
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©2009 ASQ 28
Statistical Tolerancing Example
• If the +/- 0.018 tolerance was acceptable for the
gap, we can actually set much larger componenttolerances.
• If we want all the tolerances to be the same (fiveparts and one envelope), we can calculate as:
• The component tolerances have been significantlyincreased.
22
4
2
3
2
2
2...
1 nT T T T T Tol +++++=
0073.0))(6(018.02
== T
©2009 ASQ 29
Assumptions
– The component dimensions are independent,and the components are assembled randomly.
– Each component dimension should be
approximately normally distributed.
– The actual average for each component is equal
to the nominal value stated in the specification.
©2009 ASQ 30
Progress Check
• For this example, whatshould the tolerancestack of this assemblybe, using a statistical
tolerancing approach?
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©2009 ASQ 32
Lesson 4 – Special Design Tools
IX.D.1 Strategic
Describe how Porter’s five forces analysis, portfolioarchitecting, and other tools can be used in strategicdesign and planning. (Understand)
©2009 ASQ 33
Porter’s Five Forces
• According to Kubiak and Benbow in The Certified Six Sigma Black Belt Handbook (second edition), in 1979, Michael Porterlisted five forces that affect the success of an enterprise.They are:
– The bargaining power of customers – This force represents the
ability and buying power of your customers to drive prices down
– The bargaining power of suppliers – This force represents theability and power of your suppliers to drive up prices of their products
– The threat of new entrants – This force represents the ease by
which new competitors can enter the market and drive prices down
– The threat of substitute products – This force represents the
extent to which a different product or service can be substituted foryour own
– The intensity of competitive rivalry – This force representsstrength of the competition in your industry
©2009 ASQ 34
Porter’s Five Forces (continued)
• An organization shouldanalyze each of these
as it forms its strategicplan. It should also
monitor each of theseforces continuously,because such forcescan be highly dynamic,
and changes in anyone of these forcescan require a change
in strategy.
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©2009 ASQ 35
Portfolio Architecting
• According to Kubiak and Benbow in The Certified
Six Sigma Black Belt Handbook (second edition),the steps in Portfolio Architecting are:
– Study basic physical/chemical/biologicalprinciples involved
– Use the basic principles to outline a familyof products
– List the modules required for each product
– Form a matrix with products composing therows and function modules composing the
columns
– Study the matrix to determine which productsto build.
©2009 ASQ 36
Benefits
• Product families will have more common modules.
– Improves manufacturability
– More efficient inventory management
– Allows for mass customization
See CSSBB HB, page 426 fora Product Family Matrix.
©2009 ASQ 37
Hoshin Planning
• Hoshin Planning (also called Policy Deployment)is a planning process that begins with the highestlevels of the organization.
• As goals are flowed down in the organization,
each lower level is expected to create goals
which support those at the next highest level.
• This creates alignment in the organization bothvertically as well as horizontally.
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©2009 ASQ 38
Progress Check
• Describe why you as a Black Belt should care
about:
– Porter’s Five Forces
– Portfolio Architecting
©2009 ASQ 39
Lesson 4 – Special Design Tools
IX.D.2. Tactical
Describe and use the theory of inventive problem-
solving (TRIZ), systematic design, critical parametermanagement, and Pugh analysis in designingproducts or processes. (Apply)
©2009 ASQ 40
TRIZ
• TRIZ is an acronym for the Russian phrase Teorija RezbenijaIzobretaltelshih Zadach, meaning “theory of inventive problemsolving.” Genrich Altshuller (1926-1998), a Russianmechanical engineer, created TRIZ as a set of problem-solvingdesign tools and techniques. After studying over 400,000patents looking for inventive problem-solving methods,
Altshuller noticed patterns across different industries.
• Altshuller realized that people, including specialists, havedifficulty thinking outside of their field of reference. Given aproblem (P) within their specialty, many people will only limittheir search for a solution (S) to their area of specialty.
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©2009 ASQ 41
TRIZ Concepts
When creating a design, consider these philosophicalconcepts
• Ideality – Maximize the benefits of the system and minimizethe harmful effects and costs associated with the system
• Functionality – Understanding functionality is a fundamentalbuilding block of system analysis
• Resources – Maximum utilization of resources is one of thekeys to achieving maximum Ideality
• Contradictions – Removing contradictions usually greatlyimproves functionality and raises the system to a higherperformance level
• Evolution – Grow from current knowledge where possible.
technological systems will evolve in a predictable manor.
A goal of TRIZ is to produce a system that consumes fewerresources, both in initial construction and maintenance
A goal of TRIZ is to produce a system that consumes fewerresources, both in initial construction and maintenance
©2009 ASQ 42
TRIZ Inventive Principle Example
http://www.triz40.com/
©2009 ASQ 43
Systematic Design
• Accordingly to Kubiak and Benbow in The Certified Six Sigma Black Belt Handbook (second edition),Systematic Design refers to the current trend ofapplying design principles to the design function
itself.
• Doing this will positively impact the ability to produceand execute tactical plans.
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©2009 ASQ 44
Critical Parameter Management
• Accordingly to Kubiak and Benbow in The Certified Six Sigma Black Belt Handbook (second edition),tactical planning must determine which informationis critical to the success of the plan and establish
a process for data collection and analysis. This
process is called critical parameter management(CPM).
©2009 ASQ 45
Pugh Analysis
• Sometimes also called a Decision Matrix
• Frequently used in product/process design to arriveat a superior design.
• Useful when several options are possible.
See CSSBB HB, pages 429-430 forthe development of a Pugh Matrix.
©2009 ASQ 46
Pugh Analysis Steps
• Pick a “standard” design as a baseline
• Generate a list of criteria for evaluation:
VOC: performance, requirements
VOB: business metrics (resources, DFM, DFA, projectedprofits)
• Competing designs classified as better, ‘+’, equivalent, ‘0’, orworse, ‘-’ than the datum
• Criteria can be weighted
• Reduce the number of concepts to consider – weed out ideasthat won’t work
• Goal is not to “pick the winner”
• Try combining the best from different concepts to create a“super” design.
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©2009 ASQ 47
Progress Check –True or False
1. Criteria are weighted in Pugh Analysis?
2. TRIZ means Theory of Inventive Design?
3. CPM stands for Critical Parameter Management?
4. Using Systematic Design can positively impacttactical plans?
©2009 ASQ 48
Module Status
1. Common DFSS methodologies
2. Design for X (DFX)3. Robust design and process
4. Special design tools
©2009 ASQ 49
Module 9
Exercise Solutions
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©2009 ASQ 50
Progress Check – True or False
1. DFX is applied after failures are reported by thecustomer? False
2. Design for Cost is also referred to as ValueEngineering? True
3. DFX tools could vary from industry to industry? True
4. DFM is never combined with DFA? False
©2009 ASQ 51
Progress Check Solution - StatisticalTolerancing
0023.
00000525.
002.0005.001. 222
=
=
++=Tol
©2009 ASQ 52
Progress Check –True or False
1. Criteria are weighted in Pugh Analysis? True
2. TRIZ means Theory of Inventive Design? False
3. CPM stands for Critical Parameter Management?True
4. Using Systematic Design can positively impact
tactical plans? True
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