Project Management
September 16, 2005
James R. Matt
Technical Fellow
General Motors Corp
Conventional Wisdom: A Rogue’s Gallery
“I think there is a world market for maybe five computers.”
-- Thomas Watson, chairman of IBM, 1943
“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
GTE
Siemens
Caterpillar
Philips
Pan Am
or
or
or
or
or
or
Honda?
NEC?
Hitachi?
Komatsu?
Matsushita?
British Airways?
Key Thoughts & Simple Tools
Coarse to Fine
Product Development
Select
Organize
& Prioritize
Needs
&
Ideas
Proof of
Concept
Production
Readiness
Manufacturing
&
Production
Technical
Solution
Development
Customer and
Market Feedback
(data from: Marketing, Sales, Quality,
Benchmarking, Customers)
The Force Field Model
Improved
Future State
Forces
Resisting
Change
[Constraints]
Today’s
Equilibrium
Forces
Supporting
Change
[Needs]
Today
State
The Force Field Model
Minimize Affect of
Constraints
Improved
Future State
Forces Resisting
Movement towards Vision
Movement
Towards the
Desired Future.
Increase
Forces
Supporting
Movement towards
Vision
Today
State
‘Needs’ Map
Importance vs: Satisfaction
High
High Importance
Satisfied
High Importance
High Dissatisfaction
Insure
No Loss or
Degradation
Highest
Priority
Importance
Low Importance
Satisfied
Improve if
Easy and
Low Cost
(Then, Sort for Easy
vs Difficult)
Lower Importance
High Dissatisfaction
Capture
& Work
Low
High
Low
Lack of Satisfaction
‘Needs’ Map
Importance vs: Satisfaction
Clearly
Understand
“Big Wins”
High
High Importance
Already Satisfied
High Importance
High Dissatisfaction
Insure
No Loss or
Degradation
Highest
Priority
Importance
(Then, Sort for Easy
vs Difficlut)
Low Importance
Lower Importance
But also not Satisfied High Dissatisfaction
Improve if
Easy and
Low Cost
Capture
& Work
Low
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.
High
Low
Lack of Satisfaction
Spider Chart
Performance Targets and Key Wins
Smaller
Size
Faster
Speed
Durability
Life
Today’s Product or Situation
Best in Class Competition
Targets for new Design
Spider Chart
Performance Targets and Key Wins
Smaller
Size
Faster
Speed
Durability
Life
Key Wins
Today’s Product or Situation
Best in Class Competition
Targets for new Design
Market Positioning for ####
Design Feature #### -- Projected Strategic Positioning
Parity
Focus
Win
Break-Out Metrics
Consumer Metrics
“Insider”
Technical Metrics
Brand Reputation
Selling Features
Parity
Focus
Win
Roadmap Example
Technology
Specific Technical
Solution - tbd zzzz
Gen 1
Gen 2
Gen 3
Tolerant
Controls
Integrated
Subsystem
Controls
Integrated
Vehicle
Controls
200X
GMTZZZ
2006
GMTQQQ
Utilities
2006
GMTXXX
Pickups
2002
Ford
Explorer
2001
Mercedes
S500
2004
BMW
7 Series
Legend
High Priority
Resourced
Game Changer
System or Technology – Lifecycle Plan
Long Range
Mid - Term
NA991189
Steering EPS
(High
Voltage)
GME991612
Steer By Wire
Near-Term
Performance
NA991508
Multi-Link Front Suspension,
Full Size Trucks
NA002168
Smart Tire (Sensor in Tire)
NA991217
Alternative Spring
C’ Spring
Key
NA002186
Rear Steer
(IRS Compatible)
Current
Project
NA991398
Suspension RR- IRS
Truck W/QS4
NA991190
Brakes Dry Interface
Corner Brake System
NA97041
Suspension AntiRoll DCSSS
2005
2006
2007
2008
2009
2010
Investigation
GME991612
Steer By Wire
2011
Not Staffed
2012
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
Difficult to
assemble
Method
Not Repeatable
Process
Sources of error
Tends to break
down
High Temp
Humidity
Environment
Machine
Set Priority
Map Issues & Enablers
High
Important,
Urgent
High
Priority
(Then, Sort for Easy
vs Difficlut)
Urgency
Important,
Not Yet Urgent
Capture
& Work
Low
Low
Importance
High
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
time
Define Initial Project
Task 1
Task 2
Etc
1
Define Requirements
2
Concept Generation & Selection
3
Detail Concept
4
Optimize
5
Gantt chart – Critical Path Timing
Activities are Groups of Tasks that support a
Milestone or a key decision point
Activities
time
Define Initial Project
Task 1
Task 2
Etc
1
Define Requirements
2
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’.
Concept Generation & Selection
3
Milestone isDetail
key point
in time where certain Activities or
Concept
Task are planned for completion.
The most important Milestones are often called ‘Gates’
(this example has five Gates in the green diamonds.)
Optimize
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.
4
5
Example Gantt Planning & Resources Chart
2005
2006
2007
RASIC
J F MA M J J A S ON D J F MA MJ J A S ON D J F MA MJ J A S ON D
R
A
S
name
name
name
Activities:
IDENTIFY
DEFINE
INVESTIGATE and
SYNTHESIZE
DEVELOP and VERIFY
VALIDATION TESTING
X X XX
XXXXX
name
XXXXXX
XXXXXXX
est.
XXXXXXXX
Resources:
Staffing (# people)
Veh Center
Eng Center-Chassis
Eng Center-Electrical
PE
Design
R&D
Powertrain
Mfg Center
Supplier (estimated)
Purchasing
Avg. Annual Manpower
Spending ($K)
Veh Center
Eng Center-Chassis
Eng Center-Electrical
PE
Design
R&D
Powertrain
Mfg Center
Supplier (paid by GM)
Purchasing
Total Annual Expenses
Q1
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
Q2 Q3
0.0 0.0
0.0 0.0
0.0 0.0
0.0 0.0
0.0 0.0
0.0 0.0
0.0 0.0
0.0 0.0
0.0 0.0
0.0 0.0
0.0 0.0
0.6
0.0 0.0
0.0 0.0
0.0 0.0
0.0 0.0
0.0 0.0
0.0 0.0
0.0 0.0
0.0 0.0
0.0 0.0
0.0 0.0
0.0 0.0
$0.0K
Q4
2.3
0.0
0.2
0.0
0.0
0.0
0.0
0.0
0.0
2.0
0.1
Q1
5.7
1.1
1.2
1.0
0.1
0.0
0.0
0.0
0.1
2.0
0.2
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
1.1
0.5
0.0
0.5
0.1
0.0
0.0
0.0
0.0
0.0
0.1
Q2 Q3 Q4 Q1
11.2 15.9 15.5 16.2
1.1 1.5 1.3 1.5
1.5 1.5 1.8 2.3
1.0 1.2 1.2 1.2
0.2 0.3 0.3 0.3
0.7 0.7 0.4 0.4
0.0 0.0 0.0 0.0
0.0 0.0 0.0 0.0
0.2 0.2 0.2 0.2
6.0 10.0 9.8 9.8
0.5 0.5 0.5 0.5
12.1
58.2 24.8 34.4 36.3
26.0 1.5 1.5 1.5
27.5 14.0 24.0 26.0
3.0 7.5 7.5 7.5
0.2 0.2 0.1 0.1
1.4 1.5 1.2 1.2
0.0 0.0 0.0 0.0
0.0 0.0 0.0 0.0
0.0 0.0 0.0 0.0
0.0 0.0 0.0 0.0
0.1 0.1 0.1 0.1
$118.5K
Q2 Q3
4.0 4.0
2.5 2.5
1.0 1.0
0.5 0.5
0.0 0.0
0.0 0.0
0.0 0.0
0.0 0.0
0.0 0.0
0.0 0.0
0.0 0.0
7.1
0.0 0.0
0.0 0.0
0.0 0.0
0.0 0.0
0.0 0.0
0.0 0.0
0.0 0.0
0.0 0.0
0.0 0.0
0.0 0.0
0.0 0.0
$36.3K
Q4
4.0
2.5
1.0
0.5
0.0
0.0
0.0
0.0
0.0
0.0
0.0
RASIC Choices
Bob
Eng #1
Sue
Mfg Eng
S - Supplier
Tom
Emily
etc
etc
0.0 NOTE: Cost estimates not real
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
Trade-off study matrix
Design
Option #3
Design
Option #2
Design
Option #1
Example 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
Example Criteria
Design
Option #1
Design
Option #2
Design
Option #3
Performance
++
+
+
Cost
--
++
+
-
+
0
++
0
0
0
-
0
Risk
--
+
++
Durability
++
+
-
+1
+5
+3
Mass
Quality
Volume / Size
Summation
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)
Method
1.
2.
3.
4.
5.
6.
Brainstorm Potential Problems
Define Likelihood of Occurrence (1 -10 scale)
Define Magnitude should problem occur (1-10 scale)
(Risk Priority Number) RPN = (Likelihood) X (Magnitude)
Rank order into a bar chart (Pareto Diagram)
Define Countermeasures
Pareto Diagram
Higher
RPN
(Risk
Priority
Number)
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
Specific Potential Problems
Team Work Breakdown Structure
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
Five Person Team
Team Leader
Planning
& Timing
Customer
Contact
Design
Build & Tooling
Availability
Monitor and
assess
Progress
Recorder
& Scheduling
Research
Simulation
Prototype
Build
Gate Review
Preparation
Gather Metrics
Procurement &
Cost Estimation
Trade-Off Study
Prototype
Test
Balance
Work Load
Open Issue
Management
Requirements,
Specifications
Results
Documentation
Results
Documentation
Team Work Breakdown Structure
Four Person Team
Team Leader
Planning
& Timing
Customer
Contact
Design
Build & Tooling
Availability
Monitor and
assess
Progress
Recorder
& Scheduling
Research
Simulation
Prototype
Build
Gate Review
Preparation
Gather Metrics
Procurement &
Cost Estimation
Trade-Off Study
Prototype
Test
Balance
Work Load
Open Issue
Management
Requirements,
Specifications
Results
Documentation
Results
Documentation
Team Work Breakdown Structure
Three Person Team
Team Leader
Planning
& Timing
Customer
Contact
Design
Build & Tooling
Availability
Monitor and
assess
Progress
Recorder
& Scheduling
Research
Simulation
Prototype
Build
Gate Review
Preparation
Gather Metrics
Procurement &
Cost Estimation
Trade-Off Study
Prototype
Test
Balance
Work Load
Open Issue
Management
Requirements,
Specifications
Results
Documentation
Results
Documentation
Engineering Project Management
Coarse to Fine
Product Development
Select
Organize
& Prioritize
Needs
&
Ideas
Proof of
Concept
Production
Readiness
Manufacturing
&
Production
Technical
Solution
Development
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
Production:
2
Verification:
3
Development:
4
Feasibility:
5
Idea:
Known, Proven, in Production, Refinement of existing.
Known, Proven, in Competitive Production, ‘Tribal Knowledge’ exists
Needs Verification to specific Requirements.
Known, Proven, Needs modification to meet requirements.
Known, Not Proven, Concept Demonstrated, No Production Applications,
Needs Significant Engineering Design/Analysis/Development.
Unknown, Invention required, Understand Market Pull, Need Technical Direction,
Need Technical Solution, Optimal Solution Unknown.
‘ IDDOV & Product Development
DFSS
Determine Needs,
Technology
Select Projects.
Planning
& Assign Teams
Phase 00
Product
Development
Define
Requirements,
Key Interfaces,
& Constraints
1
2
Approve Project
Plan, Team, and
& Deliverables
I - Identify
Generate
Concepts
3
Requirements
Agreement
Optimize
&
Verify
Detail
Concept
Select & Approve
Design
Concept
4
5
Approve
Detail Concept
Approve
Concept
Verification
Design for Six Sigma IDDOV
D1
Define Requirements
D2 – Design Concept
O - Optimize
V - Verify
Project Tasks and Gate Reviews
Phase 00
Product
Development
Define
Requirements,
Key Interfaces,
& Constraints
Determine Needs,
Technology
Select Projects.
Planning
& Assign Teams
Define Initial Project
Tasks:
•Determine Perf & Manf
Requirements
•Define Business Targets
•Define Needs
Define Requirements
Key Interfaces & Constraints
Tasks:
•Establish Project Plan
•Obtain Lessons Learned
•Define Project Plan &
Resources Required
Review with
key Stakeholders
Optimize
&
Verify
Detail
Concept
Concept Generation &
Design Selection
Tasks:
•Generate & Assess
Alternative concepts
Robust Assessment &
Purchasing
Tasks:
•Develop purchasing info
•Conduct Robust assessment
•Optimize Concepts
•Perform Evaluations
•Draft Initial Specifications
•Develop Commercial
Approach
•
Generate
Concepts
•Concept Tradeoff Study
• Conduct Peer Review
•Refine Specifications &
Robust Eng Plan (DOE)
•Conduct Gate Review #1
1
Approve Project
Plan, Team, and
& Deliverables
•
•Update all Business,
Technical, and Project
Documents
Conduct Concept Review
and Approve Design Concept
2
Requirements
Agreement
•
• Finalize Development
&Test Plan
• Construct, Build, and Test
Prototype
•Verify Hardware, Software
to Technical Requirements
•Define Interfaces, Constraints
•Gather Information to
determine Requirements
Optimize & Validate
Tasks:
•Develop Design
•Update all Business &
Technical Documents
Approve Details Concept
• Conduct Final Design
Make Purchasing Decisions
Review
3
Select & Approve
Design
Concept
4
Approve
Detail Concept
5
Approve
Concept
Verification
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
(& how alternatives ‘Stack up’ and why we should do one approach or another)
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.
Define what can,
(should, is)
being done to
Reduce the Risk!
5) Explain the Expected Engineering Expenses & Costs.
(Required vs: Available -- Manpower, Materials,…)
Example
Upper Strut Mount
Design For Six Sigma Example
Robust Design to ‘Band-width’
What is the ‘Better’ Design, A or B?
Performance
Variation
Operating Conditions
Design A
Design 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)
Functions
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 Bearing Friction
Smooth & Quiet
Low Rubber 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
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)
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, mispositioning, 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)
Vibration and Mechanical Shock
Dimensional Incompatibility
Physio-Chemical Instability
Matrix Functions vs Failure Mechanisms –
Evaluate Risk due to Sensitivities
React
Position
Isolate
Functions
Filter
Rotate
Limit
Amplify
Wear
Environmental
Contamination
Yield
Fracture
Creep
Failure Mechanisms
React
Position
High
Isolate
Med
Filter
High
High
Rotate
Limit
Amplify
Med
High
Wear
Environmental
Vibration and Mechanical Shock
Contamination
Dimensional Incompatibility
Physio-Chemical Instability
Yield
Fracture
Creep
Matrix Functions vs Failure Mechanisms –
Evaluate Risk due to Sensitivities
Matrix Assessment – Knowledge Gathering
The Forward Pass
Energy
Functions:
In
Position,
Isolate,
React Loads
Out
Desired Functional Characteristic
Noise Factors
Left to right -- The Forward Pass
Evaluate 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
DFSS - Front Upper Strut Mount
Functions:
Energy
Position,
Isolate,
React Loads
Desired Functional Characteristic
Position
Stays in place over life
Tolerant of misaligned mating parts
Noise Factors
(Failure Mechanisms cause Failure Modes)
Environment
Contamination
Yield
Fatigue
Fracture
Vibration / Mechanical Shock
Wear
Electrical / Software Compatibility
Physio-Chemical Instability
Creep
Dimensional Incompatibility
Isolate
Quiet over life
Noise Transmission is good
React Loads
Rate Curve is within Bandwidth
Structure handles load with out
excessive Damage
The Forward Pass
Functions:
Position,
Isolate,
React Loads
Noise Factors
Likelihood of Primary
Function being affected by a
specific Failure Mechanism
Primary Functions
Likelihood:
of compromise of a “Primary Function” due
to a Sensitivity to “Failure Mechanism”.
Strong Likelihood = “ + ”
Neutral = “ 0 ”
Not Sensitive = “ – ”
Position
Isolate
React Loads
Environment
Contamination
Yield
Fracture
Vibration / Mechanical Shock
Wear
Electrical / Software
Physio-Chemical Instability
Creep
Dimensional Incompatibility
Primary Function
Failure Mechanisms
Energy
The Reverse Pass
learn for what has happened before
Functions:
Position,
Isolate,
React Loads
Anticipated or
Historic Problems
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.
The Reverse Pass
learn for what has happened before
Functions:
Position,
Isolate,
React Loads
Anticipated or
Historic Problems
Link Historic Problems to Failure Mechanisms
Environment
Contamination
Yield
Fatigue
Fracture
Vibration / Mechanical Shock
Wear
Electrical / Software Compatibility
Physio-Chemical Instability
Creep
Dimensional Incompatibility
The Reverse Pass
Functions:
Position,
Isolate,
React Loads
Linkage of Failure Mechanisms
to Anticipated Problems
Historic and anticipated Problems
Failure Mechanism
‘Link’ to Problem :
Strong Link = “ + ”
Moderate / Not Sure = “ 0 ”
Not Linked = “ – ”
Noise at the end of life
Loss of attachment
Bearing Drag
Non-linear road feel
Environment
Contamination
Yield
Fracture
Vibration / Mechanical Shock
Wear
Electrical / Software
Physio-Chemical Instability
Creep
Dimensional Incompatibility
Noise Factors
Failure Mechanisms
Anticipated Problems
Now think in terms of the design Components (and
for competing design options)
D
E
C
F
B
G
A
H
A – Inner Metal
B – Primary/Shear Isolator
C – Upper Rate Washer
D – Reaction Washer
E – Reaction Isolator
F – Outer/Compression Isolator
G – Main Stamping
H – Lower Rate Washer
Design For Six Sigma - Front Upper Strut Mount
Desired Functional Characteristic
Orient & Position
Energy
Stays in place over life (loaded position, dynamic &
static)
Transfer Function
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,
Components:
Spring Seat
Inner Metal
Primary Isolator
Main Stamping
Outer Compression Rubber
In-Molded Metal Stamping
Upper Rate Washer
Lower Rate Washer
Bearing
Top Reaction Washer
Nuts (2)
Jounce Bumper Cup
Jounce Bumper
Dust Boot
Maintains desired Rate curves (over life, throughout
travels, dynamic frequency)
Must have mating part stiffness/mobility
React Loads
Rate Curve is within Bandwidth
Define
Structure handles load with out excessive Damage
1)Measurement Strategy for Desired Functional
Characteristics, 2) using Failure Mechanisms as Noise
Factors, 3) consider the components involved for various
design Concepts
Energy
Functions:
Forward Pass
Position,
Isolate,
React Loads
Reverse Pass
Desired Functional Characteristic
Anticipated Problems
Noise Factors
Chart the probability of each Failure Mechanism contributing to
historic problems and loss of desired Functions
Failure Mechanisms
Environment
Contamination
Yield
Fracture
Vibration / Mechanical Shock
Wear
Electrical / Software
Physio-Chemical Instability
Creep
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.
Top Mount Bearing
Create a DOE:
Contamination
Wear
Physio-Chemical Instability
Dimensional Incompatibility
X
Non-linear road feel
Bearing Drag
Loss of attachment
Noise at the end of life
React Loads
Isolate
Failure Mechanisms
Position
•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
X
X
X
X X
DOE:
•Partial Factorial Matrix experiment
•Expert Knowledge, seek help in creation
•Garbage in Garbage out (usually due to bad assumptions)
Contamination
Wear
Physio-Chemical Instability
Dimensional Incompatibility
X
Non-linear road feel
Bearing Drag
Loss of attachment
Noise at the end of life
React Loads
Isolate
Failure Mechanisms
Position
•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
X
X
X
X X
Example
Multifunction Headlamp Switch
Functions
Headlamp
On / Off
Headlamp
High / Low
Customer
Turn Signal
Cruise Control
Set, On, Off
Electrical Control
Component test plan was
designed to test each function
as independent variables
All part passed the lab test
without incident
Example
Multifunction Headlamp Switch
Functions
Headlamp
On / Off
Customer
Headlamp
High / Low
Turn Signal
Cruise Control
Set, On, Off
Electrical Control
However:
Mechanical Interaction Inside the
Multifunction 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.
Example
Multifunction Headlamp Switch
Headlamp
On / Off
Headlamp
High / Low
Customer
Electrical Control
Turn Signal
DOE factors for test matrix
Cruise Control
Set, On, Off
1) Type of Lubricant in the switch
2) Contact Material
3) Contact Plating
4) Spring Pressure
The optimal combination was found and the design was quickly changed.
No field issues were found
Causes of Problems
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
Ideas to Help
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 homework
take 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)