project management september 16, 2005 james r. matt technical fellow general motors corp
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Project ManagementSeptember 16, 2005
James R. MattTechnical Fellow
General Motors Corp
“I think there is a world market for maybe five computers.”
-- Thomas Watson, chairman of IBM, 1943
Conventional Wisdom: A Rogue’s Gallery
“There is no reason anyone would want a computer in their home.”
Ken Olson, President, Chairman and Founder of Digital Equipment Corp., 1977
“640K ought to be enough for anybody.”Bill Gates, 1981
“What do 13 people in Seattle know that we don’t?”
Ross Perot when presented with a proposal for EDS to acquire Microsoft, 1980
Conventional Wisdom: A Rogue’s Gallery
“This ‘telephone’ has too many shortcomings to be seriously considered as a means of communication. The device is inherently of no value to us.”
Western union internal memo, 1876.
“The wireless music box has no imaginable commercial value. Who would pay for a message sent to nobody in particular?”
David Sarnoff associates in response to his urgings for investment in the radio in the 1920s.
“The concept is interesting and well-formed, but in order to earn better than a ‘C,’ the idea must be feasible.”
– A Yale University management professor in response to Fred Smith’s paper proposing reliable overnight delivery service. Smith went on to found Federal Express Corp.
Dominant Positions in Business
Who would you have bet on 15 or 20 years ago?• GM or Honda?• GTE or NEC?• Siemens or Hitachi?• Caterpillar or Komatsu?• Philips or Matsushita?• Pan Am or British Airways?
Who would you have bet on 15 or 20 years ago?• GM or Honda?• GTE or NEC?• Siemens or Hitachi?• Caterpillar or Komatsu?• Philips or Matsushita?• Pan Am or British Airways?
Key Thoughts & Simple Tools
Coarse to FineProduct Development
Needs&
Ideas
Organize& Prioritize
SelectProof of Concept
TechnicalSolution
Development
ProductionReadiness
Manufacturing&
Production
Customer and Market Feedback
(data from: Marketing, Sales, Quality, Benchmarking, Customers)
The Force Field Model
TodayState
ImprovedFuture State
ForcesSupporting
Change[Needs]
ForcesResisting Change
[Constraints]
Today’sEquilibrium
The Force Field Model
TodayState
Improved Future State
Increase Forces
SupportingMovement towards
Vision
Minimize Affect of Constraints
Forces ResistingMovement towards Vision
MovementTowards the
Desired Future.
‘Needs’ MapImportance vs: Satisfaction
Importance
High ImportanceHigh Dissatisfaction
HighestPriority
Capture& Work
Low
Low
High
High
(Then, Sort for Easy vs Difficult)
Lack of Satisfaction
Lower ImportanceHigh Dissatisfaction
High ImportanceSatisfied
InsureNo Loss or
Degradation
Low Importance Satisfied
Improve ifEasy andLow Cost
‘Needs’ MapImportance vs: Satisfaction
Importance
High ImportanceHigh Dissatisfaction
HighestPriority
Capture& Work
Low
Low
High
High
(Then, Sort for Easy vs Difficlut)
Lack of Satisfaction
Lower ImportanceHigh Dissatisfaction
High ImportanceAlready Satisfied
InsureNo Loss or
Degradation
Low ImportanceBut also not Satisfied
Improve ifEasy andLow Cost
Insure you are solving the ‘Right’ problem.
Translate ‘Needs’ into Technical Requirements.
Be careful to Prioritize properly based on customer expectations.
Watch out for errors in ‘Trade-off’ decisions.
Clearly Understand “Big Wins”
Spider Chart Performance Targets and Key Wins
Today’s Product or Situation
Best in Class CompetitionTargets for new Design
FasterSpeed
SmallerSize
Durability Life
Spider Chart Performance Targets and Key Wins
Today’s Product or Situation
Best in Class CompetitionTargets for new Design
Key Wins
FasterSpeed
SmallerSize
Durability Life
Break-Out Metrics
Consumer Metrics
“Insider” Technical Metrics
Brand Reputation
Design Feature #### -- Projected Strategic Positioning
Parity Focus Win
Parity Focus Win
Market Positioning for ####
Selling Features
Roadmap ExampleP
rod
uct
Fir
st A
pp
lica
tio
nC
om
pet
itio
nT
ech
no
log
y
Gen 1 Gen 2 Gen 3
2006 GMTXXXPickups
2002Ford
Explorer
2006 GMTQQQ Utilities
200XGMTZZZ
Legend
High Priority
Game Changer
Resourced
IntegratedSubsystem
Controls
IntegratedSubsystem
Controls
IntegratedVehicle
Controls
IntegratedVehicle
ControlsTolerantControls
TolerantControls
Specific Technical Solution - tbd zzzz
2001Mercedes
S500
2004BMW
7 Series
2007
2010 2012
System or Technology – Lifecycle Plan
Per
form
ance
NA97041Suspension Anti-Roll DCSSS
2006 201120092005
NA991190Brakes Dry Interface Corner Brake System
NA991398Suspension RR- IRS Truck W/QS4
NA002186Rear Steer(IRS Compatible)
NA991217Alternative SpringC’ Spring
NA002168Smart Tire (Sensor in Tire)
NA991508Multi-Link Front Suspension,Full Size Trucks
GME991612Steer By Wire
Near-Term
Mid - Term
Long Range
NA991189Steering EPS(High Voltage)
2008
GME991612Steer By Wire
Current Project
Investigation
Not Staffed
Key
Brainstorming
• Creative thinking • Creative is highly non-linear• Synergy - Ideas tend to feed off each other and lead to bigger ideas• Do not rank ideas, or find fault with suggestions at this time• Needs time spent early in project for Creative Thinking
• Creative Capture method• Use Yellow Sticky Notes• Define Categories and repeat process on each
– Write ideas as fast as possible– Limit the time spent, go fast– Review and discuss (do not judge merit just yet)– Consolidate and re-word for concise and clear– Group into patterns
• Set aside as data needed for Project Planning and Risk Management
Fishbone (Ishikawa) Diagram
Man Method
Environment Machine
High Temp
Humidity
Difficult to assemble Not Repeatable
Process
Tends to break down
Sources of error
Set PriorityMap Issues & Enablers
Importance
Urgency
Important, Urgent
Important,Not Yet Urgent
HighPriority
Capture& Work
Low
Low
High
High
(Then, Sort for Easy vs Difficlut)
5 Phase Problem Resolution
1. Problem Definition
2. Containment, Immediate Corrective Action
3. Root Cause
4. Irreversible Corrective Action
5. Verification
Gantt chart – Critical Path Timing
Activities
Define Initial ProjectTask 1Task 2
Etc
Define Requirements
Concept Generation & Selection
Detail Concept
Optimize
1
2
3
4
5
time
Gantt chart – Critical Path Timing
Activities
Define Initial ProjectTask 1Task 2
Etc
Define Requirements
Concept Generation & Selection
Detail Concept
Optimize
1
2
3
4
5
time
The Red Line is the ‘Critical Path’.The Critical Path is the linkage path of tasks in time that if these tasks ‘slip’ the end point of the project duration becomes longer. Tasks on the this timeline are called ‘on the Critical Path’.
Activities are Groups of Tasks that support a Milestone or a key decision point
Milestone is key point in time where certain Activities or Task are planned for completion.
The most important Milestones are often called ‘Gates’ (this example has five Gates in the green diamonds.) Gates are major decision points where the project Key stakeholders approve, redirect, or stop the project.
Decisions from Gates must be clear, the issues and decision documented.
2005 2006 2007 RASIC
J F M A M J J A S O N D J F M A M J J A S O N D J F M A M J J A S O N D R A S
Activities: IDENTIFY
X X XXname name name
DEFINE X X X X X name INVESTIGATE and SYNTHESIZE X X X X X X
DEVELOP and VERIFY X X X X X X X VALIDATION TESTING est.
X X X X X X X X
Resources: Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4Staffing (# people) 0.0 0.0 0.0 2.3 5.7 11.2 15.9 15.5 16.2 4.0 4.0 4.0 RASIC Choices
Veh Center 0.0 0.0 0.0 0.0 1.1 1.1 1.5 1.3 1.5 2.5 2.5 2.5 Bob
Eng Center-Chassis 0.0 0.0 0.0 0.2 1.2 1.5 1.5 1.8 2.3 1.0 1.0 1.0 Eng #1
Eng Center-Electrical 0.0 0.0 0.0 0.0 1.0 1.0 1.2 1.2 1.2 0.5 0.5 0.5 Sue
PE 0.0 0.0 0.0 0.0 0.1 0.2 0.3 0.3 0.3 0.0 0.0 0.0 Mfg Eng
Design 0.0 0.0 0.0 0.0 0.0 0.7 0.7 0.4 0.4 0.0 0.0 0.0 S - Supplier
R&D 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Tom
Powertrain 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Emily
Mfg Center 0.0 0.0 0.0 0.0 0.1 0.2 0.2 0.2 0.2 0.0 0.0 0.0 etc
Supplier (estimated) 0.0 0.0 0.0 2.0 2.0 6.0 10.0 9.8 9.8 0.0 0.0 0.0 etc
Purchasing 0.0 0.0 0.0 0.1 0.2 0.5 0.5 0.5 0.5 0.0 0.0 0.0Avg. Annual Manpower 0.6 12.1 7.1Spending ($K) 0.0 0.0 0.0 0.0 1.1 58.2 24.8 34.4 36.3 0.0 0.0 0.0 NOTE: Cost estimates not real Veh Center 0.0 0.0 0.0 0.0 0.5 26.0 1.5 1.5 1.5 0.0 0.0 0.0 Eng Center-Chassis 0.0 0.0 0.0 0.0 0.0 27.5 14.0 24.0 26.0 0.0 0.0 0.0 Eng Center-Electrical 0.0 0.0 0.0 0.0 0.5 3.0 7.5 7.5 7.5 0.0 0.0 0.0 PE 0.0 0.0 0.0 0.0 0.1 0.2 0.2 0.1 0.1 0.0 0.0 0.0 Design 0.0 0.0 0.0 0.0 0.0 1.4 1.5 1.2 1.2 0.0 0.0 0.0 R&D 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Powertrain 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Mfg Center 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Supplier (paid by GM) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Purchasing 0.0 0.0 0.0 0.0 0.1 0.1 0.1 0.1 0.1 0.0 0.0 0.0
Total Annual Expenses $0.0K $118.5K $36.3K
Example Gantt Planning & Resources Chart
Trade-off study matrix
Desig
n
Op
tion
#1
Desig
n
Op
tion
#2
Desig
n
Op
tion
#3Example Criteria
Performance
Cost
Mass
Quality
Volume / Size
Risk
Durability
Summation
Key: “++” = Much Better
“+” = Somewhat Better
“0” = No Improvement
“-” = Worse
“ - - ”= Much Worse
Trade-off study matrix
Desig
n
Op
tion
#1
Desig
n
Op
tion
#2
Desig
n
Op
tion
#3Example Criteria
Performance
Cost
Mass
Quality
Volume / Size
Risk
Durability
++
++
++
++- -
- -
0
-
+
+
0
-
+
+
+
+
0
0
0
++
-
Summation +1 +5 +3
Key: “++” = Much Better
“+” = Somewhat Better
“0” = No Improvement
“-” = Worse
“ - - ”= Much Worse
‘Risk’
Types of Risk (things gone ‘wrong’, or critical items not going ‘right’)
• Business• Timing• Technical
Quantify Relative Risk
Risk f(L,M) = (Likelihood) X (Magnitude)
Method1. Brainstorm Potential Problems2. Define Likelihood of Occurrence (1 -10 scale)3. Define Magnitude should problem occur (1-10 scale)4. (Risk Priority Number) RPN = (Likelihood) X (Magnitude)5. Rank order into a bar chart (Pareto Diagram)6. Define Countermeasures
Pareto Diagram
RPN(Risk
PriorityNumber)
Specific Potential Problems
Focus on the high RPN Risk items and put in place Countermeasures
Must Insure --‘Bang for the Buck’(limited resources cause the need to Focus)
Lower
Higher
Team Work Breakdown Structure
Team Leader
Simulation
Design
Procurement & Cost Estimation
Recorder& Scheduling
Research
Requirements,Specifications
Planning& Timing
Trade-Off Study
CustomerContact
Results Documentation
Gate ReviewPreparation
Open IssueManagement
BalanceWork Load
PrototypeTest
PrototypeBuild
Results Documentation
Build & ToolingAvailability
Roles and responsibilities can and should be shared, moved and adjusted to assure a fair balance and to handle spikes in work.
Metrics should be set up to monitor the quality and timely delivery of work elements
Monitor and assess
Progress
Gather Metrics
Five Person Team
Team Work Breakdown Structure
Team Leader
Simulation
Design
Procurement & Cost Estimation
Recorder& Scheduling
Research
Requirements,Specifications
Planning& Timing
Trade-Off Study
CustomerContact
Results Documentation
Gate ReviewPreparation
Open IssueManagement
BalanceWork Load
PrototypeTest
PrototypeBuild
Results Documentation
Build & ToolingAvailability
Monitor and assess
Progress
Gather Metrics
Four Person Team
Team Work Breakdown Structure
Team Leader
Simulation
Design
Procurement & Cost Estimation
Recorder& Scheduling
Research
Requirements,Specifications
Planning& Timing
Trade-Off Study
CustomerContact
Results Documentation
Gate ReviewPreparation
Open IssueManagement
BalanceWork Load
PrototypeTest
PrototypeBuild
Results Documentation
Build & ToolingAvailability
Monitor and assess
Progress
Gather Metrics
Three Person Team
Engineering Project Management
Coarse to FineProduct Development
Needs&
Ideas
Organize& Prioritize
SelectProof of Concept
TechnicalSolution
Development
ProductionReadiness
Manufacturing&
Production
Customer and Market Feedback
(data from: Marketing, Sales, Quality, Benchmarking, Customers)
Technical Solution Level Indication of Risk and Time needed to bring to Market.
1
2
3
4
5
Production: Known, Proven, in Production, Refinement of existing.
Verification: Known, Proven, in Competitive Production, ‘Tribal Knowledge’ exists Needs Verification to specific Requirements.
Development: Known, Proven, Needs modification to meet requirements.
Feasibility: Known, Not Proven, Concept Demonstrated, No Production Applications, Needs Significant Engineering Design/Analysis/Development.
Idea: Unknown, Invention required, Understand Market Pull, Need Technical Direction, Need Technical Solution, Optimal Solution Unknown.
Phase 00Phase 00Define
Requirements, Key Interfaces,& Constraints
Concepts Generate Detail
Concept
Product Development
Approve ProjectPlan, Team, and & Deliverables
RequirementsAgreement
Select & Approve Design
Concept
1 2
ApproveDetail Concept
43
Optimize &
Verify
ApproveConcept
Verification
5
Technology Planning
Determine Needs, Select Projects.& Assign Teams
I - IdentifyD1
Define Requirements
D2 – Design Concept
O - Optimize
V - Verify
DFSS ‘ IDDOV & Product Development
Design for Six Sigma IDDOV
Phase 00Phase 00Define
Requirements, Key Interfaces,& Constraints
Product Development
Approve ProjectPlan, Team, and
& Deliverables
1 2 43 5
Technology Planning
Determine Needs, Select Projects.& Assign Teams
Project Tasks and Gate Reviews
Tasks:•Determine Perf & Manf Requirements
•Define Business Targets
•Define Needs
•
Review with key Stakeholders
•
Develop Commercial Approach
•
Define Project Plan & Resources Required
Tasks:
•Establish Project Plan
•Obtain Lessons Learned
•Draft Initial Specifications
•Define Interfaces, Constraints
•Gather Information todetermine Requirements
•Conduct Gate Review #1
Tasks:•Generate & Assess Alternative concepts
•Perform Evaluations
•Concept Tradeoff Study
•Refine Specifications & Robust Eng Plan (DOE)
•Conduct Concept Reviewand Approve Design Concept
Tasks:•Develop purchasing info
•Conduct Robust assessment•Optimize Concepts
•Conduct Peer Review
•Update all Business, Technical, and Project Documents
•Approve Details ConceptMake Purchasing Decisions
Tasks:•Develop Design
•Finalize Development &Test Plan
•Construct, Build, and Test Prototype
•Verify Hardware, Softwareto Technical Requirements
Conduct Final DesignReview
•Update all Business & Technical Documents
Define Requirements Key Interfaces & Constraints
Concept Generation & Design Selection
Robust Assessment & Purchasing
Optimize & ValidateDefine Initial Project
•
RequirementsAgreement
Select & Approve Design
Concept
ApproveDetail Concept
ApproveConcept
Verification
Concepts Generate Detail
Concept
Optimize &
Verify
Five Objectives of Every Gate Review
1) Explain the Benefits of the Technical Solution or Technology
2) Show the Technical Feasibility of approach and solution
3) Show the Balance of Performance to Business Imperatives
4) Explain the Risks:a) Business.b) Application Timing.c) Technical.
5) Explain the Expected Engineering Expenses & Costs.
Five Objectives of Every Design Project Review
1) Explain the Benefits of the Technical Solution or Technology
2) Show the Technical Feasibility of approach and solution
3) Show the Balance of Performance to Business Imperatives
4) Explain the Risks:(& Risk Mgt Plan, Consider Risk of doing or Not doing)
a) Business.b) Application Timing.c) Technical.
5) Explain the Expected Engineering Expenses & Costs.(Required vs: Available -- Manpower, Materials,…)
Define what can, (should, is) being done to Reduce the Risk!
(& how alternatives ‘Stack up’ and why we should do one approach or another)
ExampleUpper Strut Mount
Design For Six Sigma Example
Performance
Variation
Robust Design to ‘Band-width’
Design BDesign A
Operating Conditions
What is the ‘Better’ Design, A or B?
Define the Basic Functions
• Brainstorm a list of Basic Functions the Product must provide. “What does this thing need to do?”– Use Verbs:
• React• Position• Isolate• Filter• Rotate• Limit• Amplify• etc
Orient & Position
Stays in place over life (loaded position, dynamic & static)
Stays in place during suspension travel
Positions correctly at initial assembly
Service orientation (ex: side-load compensation)
Isolate
Quiet over life (no undesired contacts: metal to metal, contacts – click/clank, no rubber to rubber/metal relative motion - squeak,
Maintains desired Rate curves (over life, throughout travels, dynamic frequency)
Must have mating part stiffness/mobility
React & Distribute Loads
Limit Wheel Travel
Impact Forces (limit Doming of shock tower)
Maintain Suspension Geometry - React Suspension Forces (Camber, Jounce, Rebound, Spring Side Loads)
Spring, Strut Rod, Jounce Bumper – all to Body
Brake Force Reaction
Allow Rotation & Coning while steering
Low Friction
Smooth & Quiet
Low Hysterisis
Sufficient Coning Clearance & Compliance
Limit Travels
Design Travel Objective not violated (specifically: MEJ, Rebound)
Facilitate Assembly
Avoids Mis-Builds, or difficult Builds (provisions for alignment, operator adis, no interferences, retention adequate, GD&T adequate)
Tune-ability
Wide range of linear axial rates
Independently tune axial to radial rate
Volume of Rubber (shape of rate curve, and dynamic isolation)
Amount of axial pre-load (linearity, amount of linear range, rate build up)
Functions
Orient & PositionStays in place over life (loaded position, dynamic & static)
Stays in place during suspension travel
Positions correctly at initial assembly
Service orientation (ex: side-load compensation)
IsolateQuiet over life (no undesired contacts: metal to metal, contacts – click/clank, no rubber to rubber/metal relative motion - squeak, Maintains desired Rate curves (over life, throughout travels, dynamic frequency)
Must have mating part stiffness/mobility
React & Distribute Loads
Limit Wheel Travel
Impact Forces (limit Doming of shock tower)Maintain Suspension Geometry - React Suspension Forces (Camber, Jounce, Rebound, Spring Side Loads), Spring, Strut Rod, Jounce Bumper – all to Body
Brake Force Reaction
Allow Rotation & Coning while steering
Low Bearing Friction
Smooth & Quiet
Low Rubber Hysterisis
Sufficient Coning Clearance & Compliance
Limit TravelsDesign Travel Objective not violated (specifically: MEJ, Rebound)
Facilitate AssemblyAvoids Mis-Builds, or difficult Builds (provisions for alignment, operator adis, no interferences, retention
Tune-ability
Wide range of linear axial rates
Independently tune axial to radial rateVolume of Rubber (shape of rate curve, and dynamic isolation)Amount of axial pre-load (linearity, amount of linear range, rate build up)
Consider Classis Failure Mechanism that Cause Failure Modes
• Creep (relaxation and flow over time, plastic movement, often accelerated with heat or high loads)
• Fracture (brittle failure due to sudden physical overload, cracking)• Yield (Tensile or bending failure, permanent deformation)• Physio-Chemical Instability (Chemical change in material
properties, Corrosion, UV instability, chemical attack of solvent or lubricants, heat aging of rubber)
• Dimensional Incompatibility (Stack up of tolerances, mis-positioning, flexing of base or bracket, too big, too small)
• Contamination (dirt, grit, dust, mixed materials)• Vibration and Mechanical Shock (mechanical or electrical
high frequency, surge, sudden overload)• Environmental (hot, cold, humid, submersion)• Wear (repeated cyclic load causing material removal)
Matrix Functions vs Failure Mechanisms – Evaluate Risk due to Sensitivities
Cre
ep
Frac
ture
Yie
ld
Phy
sio
-Che
mic
al In
stab
ility
Dim
ensi
onal
Inco
mpa
tibili
ty
Con
tam
inat
ion
Vib
ratio
n an
d M
echa
nica
l Sho
ck
Env
iron
men
tal
Wea
r
React
Position
Isolate
Filter
Rotate
Limit
Amplify
Functions
Failure Mechanisms
Matrix Functions vs Failure Mechanisms – Evaluate Risk due to Sensitivities
Cre
ep
Frac
ture
Yie
ld
Phy
sio
-Che
mic
al In
stab
ility
Dim
ensi
onal
Inco
mpa
tibili
ty
Con
tam
inat
ion
Vib
ratio
n an
d M
echa
nica
l Sho
ck
Env
iron
men
tal
Wea
r
React
Position
Isolate
Filter
Rotate
Limit
Amplify
High
High
High
High
Med
Med
Matrix Assessment – Knowledge Gathering
Noise Factors
Functions:Position,Isolate,
React Loads
Energy
In OutDesired Functional Characteristic
Left to right -- The Forward PassEvaluate the Primary Functions and the Likelihood of the Failure Mechanisms allowing a weakness in the product design to manifest as a loss in the Desired Functional Characteristic.
Think of loss due to Noise Factors as a Signal to Noise ratio.If energy is lost in the system, then the Signal to Noise ratio must not be Unity. Attack the sensitivity of the design to the probable Noise Factors that are likely to degrade the performance.
A ‘Robust’ design is insensitive to Noise
The Forward Pass
Position
Stays in place over life
Tolerant of misaligned mating parts
Isolate
Quiet over life
Noise Transmission is good
React Loads
Rate Curve is within Bandwidth
Structure handles load with out excessive Damage
(Failure Mechanisms cause Failure Modes)Environment
ContaminationYield
FatigueFracture
Vibration / Mechanical ShockWear
Electrical / Software CompatibilityPhysio-Chemical Instability
CreepDimensional Incompatibility
DFSS - Front Upper Strut Mount
Noise Factors
Functions:Position,Isolate,
React Loads
Energy Desired Functional Characteristic
Noise Factors
Functions:Position,Isolate,
React Loads
Energy Primary Function
The Forward Pass
Position
Isolate
React Loads
Fai
lure
Mec
han
ism
s E
nvi
ron
men
tC
onta
min
atio
nY
ield
Fra
ctu
reV
ibra
tion
/ M
ech
anic
al S
hoc
kW
ear
Ele
ctri
cal /
Sof
twar
eP
hys
io-C
hem
ical
In
stab
ilit
yC
reep
Dim
ensi
onal
In
com
pat
ibil
ity
Primary Functions
Likelihood of Primary Function being affected by a specific Failure Mechanism
Likelihood: of compromise of a “Primary Function” due to a Sensitivity to “Failure Mechanism”.Strong Likelihood = “ + ”Neutral = “ 0 ”Not Sensitive = “ – ”
Functions:Position,Isolate,
React Loads
Anticipated or
Historic Problems
The Reverse Pass learn for what has happened before
Historic – ‘Things Gone Wrong’Risk concerns based on Historical Failures Applications Corrective Action
Greater deflection than planned, In bearing seal (clam shelling), allowed contamination. Lead to wear, roughness, and noise.
Increase metal thickness (stiffness), added lip seals, anti-corrosion race way, orient bearing to spring axis. Large bearing diameter allowed large clam shelling -
Lack of bearing retention resulting in displacement due to side loading
corrective action: add location features to locate and retain bearing.
Material Handling forces cause bearings to separate and balls fall out.
Add, extend snap fit tabs to keep balls in place during handling for robustness.
Fatigue life of rubber after vehicle durability test, EOL tearing
Rubber compound not as strong for new supplier. Decrease stress by Increasing rubber thickness, add volume. And changed shape.
As Loaded position of mount was not comprehended in design, redesign to offset strut rod to allow proper position at curb height.
Need to know loading position as accurate as possible, and change in load from vehicle to vehicle.
Tick noise on mount. Plastic retainer cup. Stick/slip/slapping caused a Teflon washer to be added. Click due to hard jounce bumper cup to striker plate and strut mount, on excessive coning.
Jounce bumper cup interface integrated into top mount.
Retention of jounce bumper and dust tube inadequate (rod hugger) allowed dust tube to slide down and expose rod. Corrosion of rod due to exposure. Could also cause noise.
Positive retention of dust boot and jounce bumper to strut mount, avoid rod hugger (snap fit, fastener, clamp, etc).
Long Jounce bumpers with dust boot attached to tip of jounce bumper (with large deflections) can allow dust boot to slide off at extremes of travel.
Functions:Position,Isolate,
React Loads
Anticipated or
Historic Problems
The Reverse Pass learn for what has happened before
Link Historic Problems to Failure MechanismsEnvironment
ContaminationYield
FatigueFracture
Vibration / Mechanical ShockWear
Electrical / Software CompatibilityPhysio-Chemical Instability
CreepDimensional Incompatibility
Noise Factors
Functions:Position,Isolate,
React Loads
Anticipated Problems
The Reverse Pass
Noise at the end of life
Loss of attachment
Bearing Drag
Non-linear road feel
Fai
lure
Mec
han
ism
s E
nvi
ron
men
tC
onta
min
atio
nY
ield
Fra
ctu
reV
ibra
tion
/ M
ech
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hoc
kW
ear
Ele
ctri
cal /
Sof
twar
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io-C
hem
ical
In
stab
ilit
yC
reep
Dim
ensi
onal
In
com
pat
ibil
ity
Historic and anticipated Problems
Linkage of Failure Mechanisms to Anticipated Problems
Failure Mechanism ‘Link’ to Problem :Strong Link = “ + ”Moderate / Not Sure = “ 0 ”Not Linked = “ – ”
Now think in terms of the design Components (and for competing design options)
A – Inner Metal B – Primary/Shear IsolatorC – Upper Rate WasherD – Reaction WasherE – Reaction IsolatorF – Outer/Compression IsolatorG – Main StampingH – Lower Rate Washer
A
B
C
D E
F
G
H
Orient & Position
Stays in place over life (loaded position, dynamic & static)
Stays in place during suspension travel
Positions correctly at initial assembly
Service orientation (ex: side-load compensation)
Isolate
Quiet over life (no undesired contacts: metal to metal, contacts – click/clank, no rubber to rubber/metal relative motion - squeak,
Maintains desired Rate curves (over life, throughout travels, dynamic frequency)
Must have mating part stiffness/mobility
React Loads
Rate Curve is within Bandwidth
Structure handles load with out excessive Damage
Design For Six Sigma - Front Upper Strut Mount
Transfer FunctionEnergy
Desired Functional Characteristic
Define1)Measurement Strategy for Desired Functional Characteristics, 2) using Failure Mechanisms as Noise Factors, 3) consider the components involved for various design Concepts
Components:Spring SeatInner MetalPrimary IsolatorMain StampingOuter Compression RubberIn-Molded Metal StampingUpper Rate WasherLower Rate WasherBearingTop Reaction WasherNuts (2)Jounce Bumper CupJounce BumperDust Boot
Noise Factors
Chart the probability of each Failure Mechanism contributing to historic problems and loss of desired Functions
Failure Mechanisms Environment
ContaminationYield
Fracture Vibration / Mechanical Shock
WearElectrical / Software
Physio-Chemical InstabilityCreep
Dimensional Incompatibility
In this case, Contamination, Yield, Wear, and Dimensional Incompatibility are the high Occurrence Failure Mechanism that are anticipated as the dominate Noise factors.
Functions:Position,Isolate,
React Loads
EnergyDesired Functional Characteristic
Anticipated Problems
Forward Pass
Reverse Pass
Top Mount Bearing
Create a DOE:•Consult with a DOE expert •Set up a Component Development Test •Look for sensitivity at the end of life for Failure Mechanisms: Contamination, Physio-Chemical Instability, and Dimensional Incompatibility
Failure Mechanisms Contamination
WearPhysio-Chemical Instability
Dimensional Incompatibility
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DOE:•Partial Factorial Matrix experiment
•Expert Knowledge, seek help in creation•Garbage in Garbage out (usually due to bad assumptions)
•Want a simple lab fixture(s) to run a fast DOE to understand design sensitivity to Noise factors.•Run carefully Created samples to test for interactions
Failure Mechanisms Contamination
WearPhysio-Chemical Instability
Dimensional Incompatibility
Pos
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Isol
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ExampleMultifunction Headlamp Switch
HeadlampOn / Off
HeadlampHigh / Low
Turn Signal
Cruise ControlSet, On, Off
Customer Electrical Control
Component test plan was designed to test each function
as independent variables
All part passed the lab test without incident
Functions
ExampleMultifunction Headlamp Switch
HeadlampOn / Off
HeadlampHigh / Low
Turn Signal
Cruise ControlSet, On, Off
Customer Electrical Control
However:Mechanical Interaction Inside theMultifunction Switch caused the
headlamp contact carrier to slightly rock when the Turn Signal was used.
This caused a voltage spike and high resistance path and heat in the switch.
Functions
ExampleMultifunction Headlamp Switch
HeadlampOn / Off
HeadlampHigh / Low
Turn Signal
Cruise ControlSet, On, Off
Customer Electrical Control
DOE factors for test matrix1) Type of Lubricant in the switch2) Contact Material 3) Contact Plating4) Spring Pressure
The optimal combination was found and the design was quickly changed.No field issues were found
Basic Principles – Friction, transient loads, moments, unforeseen interactions, manufacturing processes and true capabilities, marginally stable systems, static electricity, grounding
Wrong Assumptions (independence of functions in switch example)
Lack of parts available on time
Components cost more than estimated
Stack up of tolerances – reality is not design nominal
Murphy’s Law, Chaos Theory, probability and statistical theory at work
False or unachievable accuracy – How close is close enough or what can you actually obtain in the real world
Causes of Problems
Set up a good project plan with Milestones and Gate Reviews
Clearly defined Deliverables
Set up a budget (with a 10% contingency) and obtain good cost estimates and availability of materials, manpower, and facilities
Front Load your efforts – get off to a good start
Assign tasks to team members based on skill sets and personal preferences
Make progress visible, create a temporary War Room Wall and require that team members post their progress
Use Standard parts and commonly available materials - Do not invent what is already available. Focus invention on what does not already exist and yet is essential to the project.
Do your homeworktake time to study and learn as much as you can about the basic principles involved, what has
been done before, what has been written, what is the current State of the Art.Benchmarking – what is the competition doing? Brainstorm Alternatives – do not jump to the answer Allow for Experimentation – this takes twice as long as you think.Expect that ‘Things will not work right the first time’ – allow recovery time (Slack Time)
Ideas to Help
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