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ROBUST DESIGN & MANUFACTURING APPLICATIONS AT FORD MOTOR COMPANY
Dr. Yavuz GoktasReliability Technical Specialist
Ford North American Family Vehicles Quality
1st Industrial Engineering Spring ConferencesIzmir Efes Hotel, Izmir, Turkey
May 11, 2001
Define
Design for Robust Performance
Design forProducibility
Characterize
Test a
nd V
erify
PS2KO SIPS1 SC PH PA PRST LSLR
CC J1CP
ComponentSub-system
SystemVehicle
ROBUST ENGINEERING PROCESS-DFSSROBUST ENGINEERING PROCESS-DFSS
Capture the Voice of the Customer
• HISTORICAL DATA
- Campaign Actions
- Quality History
- Satisfaction Surveys
- Lessons Learned
• WANTS DATA
- Customer
- QFD
- Kano Analysis
- Regulatory
Requirements
• GENERIC DATA
-System Design Specification (SDS) &
Worldwide Customer Requirements (WCR)
- Benchmarking
• List of Critical to
Satisfaction
Characteristics (CTS’)-Ys
• Campaign Prevention Plan
• Program Specific SDS
• Design Assumptions
• High Priority Systems &
Targets
Inputs Outputs
Voice of Customer
DEFINEDEFINE
System DesignFunctional Mapping
• Relate CTS’s (ys) to
CTQs(xs)
• System DFMEA
• Component DFMEA
• Functional Targets
• Updated P-Diagram
• Noise Factor Management
Strategy
• High Impact Supplier List
OutputsInputs
System Design
Functional Mapping
• Functional Mapping
• VDS/SDS Interfaces
• Brainstorming
• P-Diagram
• D.O.E.
• CAE Models
• FEA
• Real World Usage & Environmental Profile
• Generic Design FMEA
• Supplier Quality History
CHARACTERIZECHARACTERIZE
Design for Producibility
• Model Process
(process flowchart)
• Process Data
• Gage R&R
• Process FMEA Generic
• Critical to Quality
Characteristics(CTQs-Xs)
• Characteristic and
Correlation Matrix
(Ys & Xs)
• Process Capability Model
•APQP Assessment
- Program PFMEA
- Flow Diagram
- Control Plan
• Process Capability for Xs
OutputsInputs
Design forProducibility
OPTIMIZE-MANUFACTURINGOPTIMIZE-MANUFACTURING
Design for Robust Performance
• PARAMETER DESIGN
- P-Diagram
- D.O.E.
- Optimization
• TOLERANCE DESIGN
• Customer Usage &
Environmental Profiles
• Design Verification
Plan
• Quantitative
Assessment
• Engineering
Specifications
OutputsInputs
Design for Robust Performance
OPTIMIZE-DESIGNOPTIMIZE-DESIGN
• Engineering Specifications
• Design FMEA
• Customer Duty Cycle &
Environmental Profiles
• Noise Factor Management
Strategy
• Design Verification Plan
Test and Verify• Design Verification
Plan & Report
OutputsInputs
Test a
nd
Verify
VERIFYVERIFY
CRITICAL DESIGN PARAMETERSCRITICAL DESIGN PARAMETERS
• COST
• QUALITY
• TIMING
• WEIGHT
• PACKAGING
COST REDUCTION EFFORTS COST REDUCTION EFFORTS IN ROBUST ENGINEERING PROCESSIN ROBUST ENGINEERING PROCESS
CASE STUDY 1:
COST REDUCTION & ROBUSTNESS STUDYIN THE DESIGN OF A NEW COMPOSITE NYLON INTAKEMANIFOLD
CASE STUDY 2:
A 6 SIGMA APPLICATION ON A EUROPEANVEHICLE LINE FOR NOISE REDUCTION IN THE PASSANGER CABIN
COST REDUCTION & ROBUSTNESS STUDYCOST REDUCTION & ROBUSTNESS STUDY
IN THE DESIGN OF A NEW COMPOSITE NYLON IN THE DESIGN OF A NEW COMPOSITE NYLON
INTAKE MANIFOLDINTAKE MANIFOLD
OPPORTUNITY DESCRIPTION
The conversion of cast aluminum intake manifold to glass-reinforcednylon for COST and WEIGHT improvements has uncoveredhigh frequency radiated noise sources in the air intake system.
The objectionable noise was described as hiss noise that can beeasily mistaken for engine vacuum leak. The team believes thathiss noise can easily mis-lead dealers for mis-binnings inWarranty which in turn can increase total WARRANTY COST.When no vacuum leak was discovered and the noise was traced to the intake manifold, a cross-functional team was formed to address to resolve this problem.
The goal of the team was to identify the causal factors contributingto the hiss noise and concentrate on implementing a robust, financially, technically and timely feasible solution
TEAMWORK
A cross-functional team was set-up to resolve the intake manifoldhiss noise phenomenon.
Team Member Company Position Experience Contribution
Yavuz Goktas FORD Reliability 6 yrs
Root Cause Analysis, DOE set-up, DOE analysis, DOE report, Design recom., Benchmarking
Ping K. Chao FORD NVH 7 yrs
Root Cause Analysis, NVH analysis, NVH data acquisit., Benchmarking, Correlation, Report write-up
William Weber FORD Intake Manifold Design 11 yrs
Root Cause Analysis, Intake manifold design, DOE set-up, Benchmarking, Design recom.
Kenneth W.Nelson DuPontIntake Manifold Technical Specialist 22 yrs
Root Cause Analysis, DOE set-up, DOE Hardware set-up, NVH data acqusition, Benchmarking
Don Moore FORD3.0 L V6 Duratec Engine System Design 11 yrs Management mentor, Engine PD
Yong Yu DuPont CAE Technical Support 6 yrs NVH data acqusition
PROCESS IMPROVEMENT METHODS USED
Method/Process Used Benefit
8D Process Process for structured problem resolution to hiss problem.
Cause and Effect Diagram Graphical and well structured way of identifying all the potential causal factors for hiss noise.
Design of Experiments
Helps to identify siginificant factors contributing to hiss noise and recommends the best design configuration to minimize hiss noise
Orthogonal Arrays Structure way of setting-up a design of experiments
Analysis of Variance Identifies significance level of each causal factor in the hiss noise index
Main Effects Plot
Graphical results of Analysis of Variance. Helps the team to select the best levels of significant factors to minimize the hiss noise index.
General Linear Model
Helps the team to model the hiss noise phenomenon statistically to come up with the best statistical model to minimize hiss noise.
Correlation Study
Helps to corrolate subjective rating with objective rating to find the best frequency bandwith for objective DOE measurement.
Benchmarking Benchmarks our initial and final design with that of Best-in Ford and Best-in-Class.
NVH Analysis
Helps to look at the problem from customer point of view as subjective evaluation of the hiss noise and NVH point of view as objective evaluation of the hiss noise
PROBLEM RESOLUTION PROCESS FLOW CHARTPROBLEM RESOLUTION PROCESS FLOW CHART
SET-UP TEAM
DEVELOP CAUSE & EFFECT DIAGRAM
PLAN DOE
PERFORM DOE
ANALYZE DOE
CONFIRM DOE
PERFORM BENCHMARKING IMPLEMENT DESIGN
CAUSE AND EFFECT DIAGRAMCAUSE AND EFFECT DIAGRAM
HISSNOISE
INTAKE MANIFOLD THROTTLE BODYT-Body Hole
Taped
No Tape
T-BodyPlenum
Sharp
Blended
Plenum SurfaceTexture
Rods Rounded
Sharp
IACV Location
DirectRemote
IACV
IACV Channel Surface
Smooth
Tapered
Scoop
Yes
No
Nominal
50% thicker
Diffuseryes
no
Thickness
Rib Inserts
None
Yes
SCREENING DOESCREENING DOE
The goal of the screening DOE was to identify significant designparameters contributing to intake manifold hiss noise and carryout further robustness studies to recommend design actions tominimize/eliminate hiss noise.
FACTORS & LEVELS OF DOE
Levels
1 2
T-Body/Plenum Sharp Blended
IACV Mount Location Direct Remote
IACV Channel Surface Smooth Tapered
Factors Plenum Surface Texture Sharp Rods Rounded
Honeycomb Diffuser None Diffuser
Intake Thickness Nominal 50% thicker
T-Body Hole No Tape Taped
Scoop Insert No Yes
Rib Division Inserts None Yes
INTAKE MANIFOLD
THROTTLE BODY PLATE
HONEYCOMB DIFFUSER
IACV MOUNT LOCATION
T-BODY/SCOOP INSERT/IACV
FACTORS
T-BodyIACV
Location
IACV Channel Surface
Plenum Surface Texture HoneyComb
Intake Thickness
T-Body Hole
Rib Inserts Scoop
1 1 1 1 1 1 1 1 1 2
2 1 1 1 2 2 2 2 1 1
3 1 1 2 1 2 2 1 2 1
4 1 1 2 2 1 1 2 2 2
5 1 2 1 1 2 1 2 2 1
6 1 2 1 2 1 2 1 2 2
7 1 2 2 1 1 2 2 1 2
RUN # 8 1 2 2 2 2 1 1 1 1
9 2 1 1 1 1 2 2 2 1
10 2 1 1 2 2 1 1 2 2
11 2 1 2 1 2 1 2 1 2
12 2 1 2 2 1 2 1 1 1
13 2 2 1 1 2 2 1 1 2
14 2 2 1 2 1 1 2 1 1
15 2 2 2 1 1 1 1 2 1
16 2 2 2 2 2 2 2 2 2
DOE TEST MATRIX
QUALITY CHARACTERISTICS
1. Subjective Evaluation
A jury of 10 engineers aged between 20 to 50 years old andcame from different fields were asked to listen recordings ofnoise and rate their preferences based on the following table:
Subjective Rating Definition
1 Noisy hiss
2 Objectionable hiss
3 Borderline acceptable
4 Acceptable hiss
5 Very good
2. Objective Evaluation:
Overall sound pressure level with a pre-set high frequencybandwith is determined to be an appropriate index to representhiss noise. Two high frequency bandwiths as 6kHz-16kHz and8KHz-16KHz were chosen as the noise indices for hiss noisedue to strong correlation between subjective and objectivemeasurement of the hiss noise.
Subjective/Objective Correlation for Frequency Bandwith 6K-16K Hz
60
62
64
66
68
70
72
1 1.5 2 2.5 3 3.5 4 4.5 5 5.5
Subjective Rating
Ob
ject
ive
Me
asu
rem
en
t (d
B(A
))
Subjective/Objective Correlation for Frequency Bandwith 8K-16K Hz
56
58
60
62
64
66
68
70
1 1.5 2 2.5 3 3.5 4 4.5 5 5.5
Subjective Rating
Ob
ject
ive
Me
asu
rem
en
t (d
B(A
))
EXPERIMENT AND DATA ACQUISITION
DOE Run# Average Subjective Ratings Mic. 3 energy 6k-16k Hz dB(A) Mic. 3 energy 8k-16k Hz dB(A)
1 2.2 69.7 67.7
2 3.2 67.1 62.9
3 3.3 65.2 63.3
4 2.1 68.9 65.2
5 4.2 64.0 61.2
6 3.5 65.9 62.5
7 3.3 62.2 58.9
8 2.1 68.7 67.1
9 2.8 67.2 64.0
10 1.7 70.3 68.4
11 3.1 67.6 63.8
12 3.1 66.6 63.1
13 3.6 66.1 63.8
14 2.9 65.6 62.7
15 2.1 69.4 68.1
16 5.0 61.8 58.0
DATA ANALYSIS
The significance of the nine main factors on hiss noise was determined statistically by using General Linear Model(GLM) procedure of the statistical package MINITAB.
Analysis of Variance and Main Effect plots were utilized todraw conclusions regarding significance of the nine mainfactors on hiss noise
DATA ANALYSIS (continued)
P Value Subjective 6K-16K Hz Bandwidth 8K-16K Hz Bandwidth
T-Body 0.89 0.69 0.69
IACV Loc 0.12 0.04 0.07
IACV Cha 1 0.56 0.48
Plenum S 0.74 0.62 0.91
Honeycomb 0.19 0.55 0.64
Intake Thickness 0.04 0.02 0.01
T-Body Hole 0.13 0.05 0.01
Rib Insert 0.69 0.9 0.93
Scoop 0.79 0.86 0.61
ANALYSIS OF VARIANCE: P-Values
DATA ANALYSIS (continued)
MAIN EFFECTS PLOT: SUBJECTIVE MEASURE
Decision Criterion: The bigger-the better
ScoopRib InseT-Body HIntake THoneycomPlenum SIACV ChaIACV LocT-Body
3.4
3.2
3.0
2.8
2.6
Subjec
ti
Main Effects Plot - Means for Subjecti
DATA ANALYSIS (continued)
MAIN EFFECTS PLOT: OBJECTIVE MEASURE (6K-16K Hz)
Decision Criterion: The smaller-the better
ScoopRib InseT-Body HIntake THoneycomPlenum SIACV ChaIACV LocT-Body
0.050
0.047
0.044
0.041
0.038
Mic. 3
Main Effects Plot - Means for Mic. 3
DATA ANALYSIS (continued)
MAIN EFFECTS PLOT: OBJECTIVE MEASURE (8K-16K Hz)
Decision Criterion: The smaller-the better
ScoopRib InseT-Body HIntake THoneycomPlenum SIACV ChaIACV LocT-Body
0.038
0.035
0.032
0.029
0.026
Mic. 3
Main Effects Plot - Means for Mic. 3
Two full factorial DOEs were conducted on IACV locationand T-Body to further study their contribution to the hiss noise.
FOLLOW-UP ROBUSTNESS STUDIES
RunTotal Area (sq mm)
Hole Diameter (mm)
Thickness(mm)
1 127 3 2.52 200 3 2.53 127 5 2.54 200 5 2.55 127 3 56 200 3 57 127 5 58 200 5 5
RunHole Diameter
Lateral Positioning (mm)
Vertical Positioning (mm)
1 0.072'' 8 122 0.107" 8 123 0.072'' 16 124 0.107" 16 125 0.072'' 8 246 0.107" 8 247 0.072'' 16 248 0.107" 16 24
DOE Matrix for Throttle Body HoleDOE Matrix for IACV Pattern
CONCLUSION
Statistical analysis using GLM on both subjective and objectivehiss noise measurements concluded with high confidence thatthe following factors are significant for hiss noise:
• Intake manifold thickness• Throttle Body Hole• IACV Location
The team recommended that the following factor/level settings beUsed to minimize the hiss noise:
50% thicker Intake manifold- Implemented for 2000 MY Holes in the Throttle Body - Implemented for 2000 MY Remote IACV - To be implemented for future program Honeycomb diffuser - Implemented for 2001 MY
RESULTS
HISS NOISE RESULTS
72
57
61
50
55
60
65
70
75
D186Composite
Nylon (Before)
D186 Optimizedwith DOE
D186Implemented
Design
Design Level
His
s N
ois
e(d
B(A
))
AN 11 dB(A) IMPROVEMENT IN THE INTAKE MANIFOLD HISS NOISE!!!!!!
MAINTAINING THE QUALITY IMPROVEMENT
Two presentations given to EDQR during the hiss noise resolution process A presentation given at PT NVH PAT
The full report of the project is included in the Ford Web at:
http://www.poee.ford.com/VEE/doc/Components/B/Intake/news/intakdoe.html
Published at the ‘99 International SAE Conference (Ref.#: 1999-01-1228)
The team is in the process of submitting the full report of the project to the Ford technical Journal
Shared the findings of the project with Puma Diesel Engineering
A. Lessons Learned/Awareness
B. Benchmarking
Vehicle Hiss Noise Index Benchmarking Results
72
57
61
63
59
50
55
60
65
70
75
80
Toyoto Camry(Aliminum intake)
DN101 AluminumIntake
D186 CompositeNylon (Before)
D186 Optimized withDOE
D186 ImplementedDesign
Benchmarked Intake Manifolds
His
s N
ois
e In
de
x (
dB
(A))