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))