FMEA - Product Development

GQ Huang (HKU)

FMEA-QFD-1

The University of Hong Kong http://imse2114.autom.hk/FMEA-QFD-1The University of Hong Kong

Focused appraisal with formal methods/techniques

General understanding of the product. What does the product look like? What does the product consists of? How (well) does the product work and how is it used??

Lifecycle appraisal with “Design for X” What makes a good product I? - Key Performance Indicators What makes a good product II? - Key Product Characteristics What makes a good product III? - Key Process Characteristics “Design for X” Safety, Environment, Manufacture and Assembly, Ergonomics and Esthetics etc.

Focused appraisal with formal methods/techniques FMEA QFD

Market and Technology Appraisal Perception Mapping Market segmentation Product life cycle

The University of Hong Kong http://imse2114.autom.hk/

FMEA stands for

Failure Modes and Effect Analysis

Introduction


What is FMEA ?

Failure Modes and Effects Analysis (FMEA) is a structured analytical technique for assessing risk during product development to identify early corrective action.

Structured group of activities which... Identify potential failure modes Prioritize actions Document the process.


FMEA – Purpose

Failu

res

Time

FMEA

GQ Huang (HKU)

FMEA-QFD-2


Typical Applications of FMEA?

From very simple products

To very sophisticated products

•Aerospace•Automotive•Chemical processes•Nuclear •Consumer products•Software products•Service products•Etc.


What benefits does FMEA bring?

Early identification of problems “Right first time” design Reduced scrap Improved product reliability Reduced warranty returns Appropriate recommended actions may not have been taken. Savings in engineering time. Reduction of changes immediately before production start

(Commercial Release).


Brief History of FMEA

It has been the result of continuous crystalization of good practices in design engineering, quality and reliability engineering.

1920s – Good practices start emerge 1950s – Become standards in USA and UK 1970s-1980s

Widely adopted across the industrial spectrum Usually intensive short-course training – very expensive

Since 1990s Contractual requirements in several industrial sectors Widely taught to college students


Item Function

Class

Severity

Potential EffectOf Failure

PotentialFailure Mode

Responsibility& Target

CompletionDate

RecommendedActions

RPN

Detection

Current DesignControls

Occurrence

PotentialCause(s) /

Mechanism(s)Of Failure

Overview of FMEA Worksheet

FMEA Number Prepared By FMEA Date

Component Starlock Washer Assembly H/Lamp Adjuster Core Team

Design Responsibility Key Date

GQ Huang (HKU)

FMEA-QFD-3


FMEA Analysis Procedure

Part Function

Potential Failure mode

Calculate RPN’sCalculate RPN’s

Effects Of Failure Severity Rating

Cause Of Failure Occurrence Rating

Design Control Detection Rate

ActionsActions

Robust Design

RPN = Risk Priority Number


Determine Items and their Functions

Similar to what we have discussed on using BOM for Functional Analysis.

List all product items (in the form of BOM) Identify and describe all functions for each Item


CompletionDate

RecommendedActions

RPN

Detection


Occurrence

PotentialCause(s) /


Class

Severity



Item Function


Verb

Indicates action, occurrence, being

GenerateControlDisplay

Noun

Indicates what the action relates to

Describe Function

lightspeedinformation


Failure Mode – How does it fail?

Consider the Failure Modes of “Body” of Ball-Point Pen. - -

Consider the Failure Modes of “Tube Sub-Assembly” of Ball-Point Pen. - -


CompletionDate

RecommendedActions

RPN

Detection


Occurrence

PotentialCause(s) /


Class

Severity



Item Function

GQ Huang (HKU)

FMEA-QFD-4


Effects of Failure (Modes) – Consequence/Impacts

What are the effects of the failure relating to: - another part - the complete assembly - the customer - the enduser - the governmental regulations


CompletionDate

RecommendedActions

RPN

Detection


Occurrence

PotentialCause(s) /


Class

Severity

Potential Effect

Of Failure


Item Function


Effects of Failure (Modes) – Examples

Consider the Effects of the Failure Mode - “Not comfortable to hold” of “Body” of Ball-Point Pen. - -

Consider the Effects of the Failure Mode – “Irregular/messy lines” of “Tube Sub-assembly” of Ball-Point Pen. - -


CompletionDate

RecommendedActions

RPN

Detection


Occurrence

PotentialCause(s) /


Class

Severity

Potential Effect

Of Failure


Item Function


Severity (S) – How Serious?

Consider the Effects of the Failure Mode - “Not comfortable to hold” of “Body” of Ball-Point Pen. - “Bad writing” - Concerned - “Painful fingers” - Concerned

Consider the Effects of the Failure Mode – “Irregular/messy lines” of “Tube Sub-assembly” of Ball-Point Pen. - “Bad report” -> “Loose job” -> “Extremely serious” -


CompletionDate

RecommendedActions

RPN

Detection


Occurrence

PotentialCause(s) /


Class

Severity



Item Function


Effect of Failure Cause of Failure Design Controls

DETECTIONOCCURRENCE

Almost Never

Occasionally

Often

SEVERITY

Hardly Noticeable

Dissatisfaction

Serious Effects

Absolutely Obvious

Could Go Unnoticed

Undetectable

RATING

1

10

5

FMEA Rating Criteria –Severity

How often? What checks?How bad is it?

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FMEA-QFD-5


Potential Cause of Failure – What causes the failure?

Consider the Cause(s) of the Failure Mode - “Not comfortable to hold” of “Body” of Ball-Point Pen. - -

Consider the Cause(s) of the Failure Mode – “Irregular/messy lines” of “Tube Sub-assembly” of Ball-Point Pen. - -


CompletionDate

RecommendedActions

RPN

Detection


Occurrence

PotentialCause(s) /


Class

Severity



Item Function


Potential Cause of Failure – Sources of the Cause

A cause may be rooted at the “Design Stage” – Under designed

A cause may be rooted at the “Production/Delivery Stage” – Poor quality control

A cause may be rooted at the “Use Stage” – Improper uses


CompletionDate

RecommendedActions

RPN

Detection


Occurrence

PotentialCause(s) /


Class

Severity



Item Function


Manufacturing misbuilds

Due to design Deficiencies

-+

+-


Manufacturing misbuilds

Robust Design

+-

+-

GQ Huang (HKU)

FMEA-QFD-6


Occurrence (O) – How often does it cause the failure?

Consider the Cause(s) of the Failure Mode - “Not comfortable to hold” of “Body” of Ball-Point Pen. - “Shape Cross Section” (Design, O = 1) -

Consider the Cause(s) of the Failure Mode – “Irregular/messy lines” of “Tube Sub-assembly” of Ball-Point Pen. - “Tolerance between “Ball” and “Seat” is too large” (Manufacturing, O = 6) - “Temperature is too high” (Use Environment, O = 7)


CompletionDate

RecommendedActions

RPN

Detection


Occurrence

PotentialCause(s) /


Class

Severity



Item Function



DETECTIONOCCURRENCE

Almost Never

Occasionally

Often

SEVERITY

Hardly Noticeable

Dissatisfaction

Serious Effects

Absolutely Obvious

Could Go Unnoticed

Undetectable

RATING

1

10

5

FMEA Rating Criteria – Occurrence



Design Controls and Detection Methods – How do you detect the failure?

How do you detect the failure “Uneven line thickness” of Ball-Point pen? “Visual observation”

How do you detect the tolerance of the gap between the “Ball” and “Seat” of Ball-Point pen? “Special equipment”


CompletionDate

RecommendedActions

RPN

Detection


Occurrence

PotentialCause(s) /


Class

Severity



Item Function


Design Controls – Detection (D)

How do you detect the failure “Uneven line thickness” of Ball-Point pen? “Visual observation” – “Very Easy” (1)

How do you detect the tolerance of the gap between the “Ball” and “Seat” of Ball-Point pen? “Special equipment” – “Very Difficult and Expensive – Need to

be professionally done” (9)


CompletionDate

RecommendedActions

RPN

Detection


Occurrence

PotentialCause(s) /


Class

Severity



Item Function

GQ Huang (HKU)

FMEA-QFD-7



DETECTIONOCCURRENCE

Almost Never

Occasionally

Often

SEVERITY

Hardly Noticeable

Dissatisfaction

Serious Effects

Absolutely Obvious

Could Go Unnoticed

Undetectable

RATING

1

10

5

FMEA Analysis Criteria - Detection



RPN- Risk Priority Numbers

RPN (Mode) = S * O * D (Product of S, O and D ratings) RPN(Function) = Sum of RPNs of all the failure modes. RPN(Item) = Sum of RPNs of all the functions RPN(Product) = Sum of RPNs of all the items

What should be done if a Failure Mode has more than one Effects/Causes/Detections?


CompletionDate

RecommendedActions

RPN

Detection


Occurrence

PotentialCause(s) /


Class

Severity



Item Function


Interpreting RPNs – FMEA Results

The higher the RPN is, the ... The lower the RPN is, the ...

Actions should be recommended for those items with higher RPNs.

More design time and efforts should be allocated and dedicated to items with higher RPNs.


CompletionDate

RecommendedActions

RPN

Detection


Occurrence

PotentialCause(s) /


Class

Severity



Item Function


Planning for Actions

Identify those functions and items with high RPNs. Recomend actions in order to

Eliminate the cause of failure Minimize the effect of failure Reduce the frequency of failure/cause Faciltate failure detection and control Faciltate failure recovery Etc.


CompletionDate

RecommendedActions

RPN

Detection


Occurrence

PotentialCause(s) /


Class

Severity



Item Function

GQ Huang (HKU)

FMEA-QFD-8


Managing FMEA’s

Who should take the recommended action(s)? When should the action(s) start and finish?


CompletionDate

RecommendedActions

RPN

Detection


Occurrence

PotentialCause(s) /


Class

Severity



Item Function


What process or system or controls are in place to identify or prevent a failure ?

Effect

Cause

Mode of Failure

What effect may the failure have ?

How could ‘it’ fail ?

What may cause the failure ?

Controls

Determining Causes & Effects


CompletionDate

RecommendedActions

RPN

Detection


Occurrence

PotentialCause(s) /


Class

Severity



Item Function


Example - Headlamp Adjuster

Knob

Insert

Starlock washer

Rubber washer

Screw

Headlamp body


Example - Headlamp Adjuster

Item Function



Severity

Class

PotentialCause(s) /


Occurrence


Detection

RPN Recommended

Actions


CompletionDate

Secures the insert and Rubber washerassembly into the headlampbody

Flips to reverseangle

Falls off dueto reduced gripon insert

8Material too thinto support rubber

2Provenprinciple

1 16

8

Insert diametertoo small tocreate correctlocking angle

2Known design principle

3 46

8Washer innerdiameter too big

2Supplied proprietary item

1 16

CracksFalls off dueto reduced gripon insert

8

Excessive assyforce due tooversize insertdia

2Known design principle

2 32

8Incorrectheat treatmentspecified

2Supplied proprietary item

3 48

GQ Huang (HKU)

FMEA-QFD-9


Example - Ball-Point Pen

Item Function



Severity

Class

PotentialCause(s) /


Occurrence


Detection

RPN Recommended

Actions


CompletionDate


QFD stands for

Quality Function

Deployment


What is QFD?

Translates the voice of the customer into the will of the enterprise. Customer’s voice

in the language of the customer Will of the enterprise

in the technical language of design and manufacturing


QFD – Purpose…

Translate consumer’s voice into technical design requirements Determine & prioritize customer needs Translate customer needs to product design parameters

Coordinate efforts and skills of an organization from a project’s inception to its completion

Ensure customer expectations Avoid manufacturing catastrophe

Cobe1

Slide 36

Cobe1 QFD enables an organization to direct efforts on customer requiremtnts for which a product might not be competitive

thus activites in the company are prioritized according to the level of concern for customer satisfactionCOBEguest, 27/04/2002

GQ Huang (HKU)

FMEA-QFD-10


History…

1972 Japan Mitsubishi Introduced to USA To Europe Part of Total Quality Management Valuable tool Underused Fundamental to success

Cobe2


QFD can be used to:

Reduce product development time by 50% Cut start-up & engineering costs by 30% Reduce time to market Reduce # of design changes Lower rework Reduce facility’s maintenance/operation costs Improve quality


More Benefits

Improved client Satisfaction Reduced Development Time Improved Internal Communications Better Documentation of Key Issues Save $$ Money $$ 25,000 professionals and over 500 companies have realized major improvements in client satisfaction using QFD, achieving: a method to "design-in" quality proactively reduced changes in product/process development identified need for changes before making major expenditures reduced product development time fewer start-up problems reduced field problems reduced warranty costs creation of a design knowledge base integrating the "Voice of the client" into the development process company understanding of client's needs, even better than the clients themselves do For those professionals committed to driving the "voice of the client" into their products and services, this method will: Increase client satisfaction Reduce the number of design changes Reduce variability throughout the development cycle Reduce the number of start-up problems Reduce the total development time Create a proprietary client-driven database of knowledge for the organization Products meet customer expectations better Provides improved design traceability Reduced lead times through fewer design changes and focus on key features Reduced product cost through use of appropriate tolerances and reduced scrap Improved communication within organisation and with customer


Benefits of QFD

BEFORE QFD AFTER QFD

Individual Work Cross-functional Teams

Some client Focus Intense client Focus

"Over the Wall" Development Supports Simultaneous Engineering Poor Documentation Supports

Integrated Product Development Poor Communications Better Communication/ Documentation

Slide 37

Cobe2 QFD was concieved in 1972 by the Japanese company, Mitsubishi Heavy Industries Ltd. as part of their TQM system.COBEguest, 27/04/2002

GQ Huang (HKU)

FMEA-QFD-11


Quality Function Deployment

The House of Quality – The QFD Worksheet


The House of Quality

Technical Benchmarking

Inter relationships

Cus

tom

erR

equi

rem

ents

Mar

ket /

Cus

tom

er

Prio

ritie

s

TechnicalRequirements

Roof

Technical Priorities

Mar

ket

Ben

chm

arki

ng

Technical Targets


Typical QFD 1 Chart


QFD 1 Analysis Procedure

Priority Setting

Design Requirements

Target Values

Market /Product Strategy

Customer Requirements

Relationship Setting

Complete Matrix

Define Product Plan & Specification

Competitor Benchmarking

Technical Benchmarking

Note : QFD is a highly iterative process. Involvement from Customers is vital though out

GQ Huang (HKU)

FMEA-QFD-12


QFD process – Key Steps

Identify customer requirements Importance ratings Competitor assessment

Derive design requirements Target values Correlation Competitor benchmarking

Plot relationships Prioritise design requirements


Pencil Example

Importance

Weighting

Cross

section

Paint

Lead

Tube m

aterial

Length

Label

Market

Priorities

Existing

Com

petitor #1

Com

petitor #2

Technical Trend

Technical difficulty

Does not roll 7 18

Does not smell

Comfort of holding 8

Technical Priorities 18 10 12

Existing

Competitor #1

Competitor #2

Target System


Pencil Example

Importance

Weighting

Cross

section

Paint

Lead

Tube m

aterial

Length

Label

Market

Priorities

Existing

Com

petitor #1

Com

petitor #2

Technical Trend


Does not roll 7

Does not smell 5



Existing

Competitor #1

Competitor #2

Target System



Identify stakeholders Determine Customer Requirements Group customer requirements Identify principal customer Determine Importance Ratings

GQ Huang (HKU)

FMEA-QFD-13



Can you think of one more example from “Pencil Retailer’s point of view?

Importance

Weighting

Does not roll 7

Does not smell



Design Requirements

Derive design requirements from customer requirements Group Design Requirements Technical trends

The larger the better The smaller the better Target value is the best.

Technical difficulties Cost of implementation Etc.


Design Requirements

Importance

Weighting

Cross section

Paint

Lead

Tube material

Length

Label

Technical Trend


Does not roll 7

Does not smell



Relationships

Identify strong, medium & weak relationships “Does the design requirement help to satisfy the customer

requirement?” Work along rows Important rows first

Prioritise design requirements

GQ Huang (HKU)

FMEA-QFD-14


Interrelationships

Between customer requirements and technical requirements Translation and correlation step Critical to generate consensus between development team and

customers. Critical Question:

How significant is technical requirement A in satisfying customer requirement B?


Interrelationships

- Strong - Medium - WeakBlank – No relation? – Relationship undefined.

Importance

Weighting

Cross section

Paint

Lead

Tube material

Length

Label

Technical Trend


Does not roll 7

Does not smell



Market / Customer Priorities


Importance

Weighting

Cross section

Paint

Lead

Tube material

Length

Label

Market Priorities

Technical Trend


Does not roll 7 18

Does not smell





Importance

Weighting

Cross section

Paint

Lead

Tube material

Length

Label

Market Priorities

Technical Trend


Does not roll 7 18

Does not smell



GQ Huang (HKU)

FMEA-QFD-15


Interpreting QFD Results

Rows with higher priorities –

Rows with lower priorities –

Columns with lower priorities –

Columns with lower priorities –


“The Roof”

Considers impact of technical requirements on each other Feature to feature comparison Augment or impede?

Purpose: Tradeoff between technical requirements

Critical Question: Does improving one requirement cause a deterioration or

improvement in another requirement?


“The Roof”

Legend+ Positive supporting- Negative tradeoff

Mee

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Har

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wei

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Web

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stre

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Padd

ing

thic

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Web

bing

stre

ngth

Padd

ing

thic

knes

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Competitive (Market) Benchmarking

Importance

Weighting

Cross section

Paint

Lead

Tube material

Length

Label

Market

Priorities

Existing

Com

petitor #1 C

ompetitor

#2

Technical Trend


Does not roll 7 18 5 2 3

Does not smell 4 5 2



GQ Huang (HKU)

FMEA-QFD-16


Competitive (Technical) Benchmarking

Importance

Weighting

Cross

section

Paint

Lead

Tube m

aterial

Length

Label

Market

Priorities

Existing

Com

petitor #1

Com

petitor #2

Technical Trend

Technical difficultyDoes not roll 7 18

Does not smell



Existing 3 5Competitor #1 2 3Competitor #2 5 2


Technical Targets

Summarize previous steps Draw conclusions Consists of:

Technical Priorities Competitive Benchmarks Final Product Targets

Results from previous steps: Customer requirements Prioritized customer requirements Technical requirements Correlated requirements Feature interdependencies


Technical Targets

Importance

Weighting

Cross

section

Paint

Lead

Tube m

aterial

Length

Label

Market

Priorities

Existing

Com

petitor #1

Com

petitor #2

Technical Trend


Does not roll 7 18

Does not smell



Existing

Competitor #1

Competitor #2

Target System


House of Quality Summary

Inputs: Customer requirements Technical requirements Customer priorities Market reality / competitive analysis Organization’s strengths & weaknesses

Outputs Prioritized technical requirements Measurable, testable goals

GQ Huang (HKU)

FMEA-QFD-17


House of Quality Pros and Cons

Pros: Generates specific technical requirements Requirements are traceable Follows a repeatable, quantitative process Effectively translates Voice of the Customer Records rationale for each technical requirement

Cons: Time-consuming process for >10 requirements Data storage, manipulation and maintenance costs Very dependent on customer requirement gathering Inflexible to changing requirements; must recalculate


Closures

Customers tell us that they like closures that are: Easy to open Easy to close, AND

Customers also tell us that they dislike Road noise Water leaks


Summary-QFD & The House

Helps engineers to choose engineering characteristics of and set targets related to product performance.

Forces tough decisions and trade-offs to be addressed early in the PDP.

Serves as a corporate memory of important issues related to product innovation.


Phases of QFD

QFD applies not only to product planning stage, but also downstream stages …

GQ Huang (HKU)

FMEA-QFD-18


Deploying CA’s Downstream

The house of quality can be used to deploy the voice of the customer to all elements of the product realization process.


Phase 1Product Planning

Phase 2Part

Development

Phase 3Process Planning

Phase 4Production

Planning

1

ProductionRequirements

DesignRequirements

PartCharacteristic

Req

uire

men

ts

ProcessOperations

Cus

tom

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ants

Key

Des

ign

Key

Par

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hara

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s

Key

Proc

ess

Ope

ratio

ns

The Phases of QFD


Managing FMEA and QFD

They are team-building tools. They must be used as such in order to

Facilitates communication betweenCustomersMarketing

Product developmentEngineering

Manufacturing, andService


FMEA and QFD

Are design tools, which Facilitates communication between

Customers Marketing Product development Engineering Manufacturing, and Service

GQ Huang (HKU)

FMEA-QFD-19


Team

Design-Enginieer

Production/ process-enginieer

Core-team

Representitives from:

• development

• production

• quality

• purchase

• testdept.

• ...

Supportteam

Facilitator


Generating FMEA/QFD

Who initiates?

FMEA/QFD

Who updates?

Who is FMEA/QFD -customer?

Startingdate/revisiondate?

When completed?

How docu-mented?

When to discard?

Who prepares?


FMEA – Team Approach

Core-team

Support-team


Car Door Case Study

GQ Huang (HKU)

FMEA-QFD-20


To Learn More

Houser, J.R., D.P. Clausing, “The House of Quality”, Harvard Business Review, vol. 66, no. 3, pp. May-June 1988, 63-73.

D.P. Clausing, Total Quality Development, ASME Press, 1994


Voice of the Customer-CA’s

What does the Customer REALLY Mean? Quiet? Easy? What is a water leak?

Customer Attributes Stated in the language of the customer Usually must be decomposed


CA’s for a Car Door

Good operation and use Easy to open and close door Isolation Arm rest Easy entrance and exit

Good appearance Interior trim Clean Fit


Easy to Open and Close

Door Easy to close from outside Easy to close from inside Easy to open from outside Easy to open from inside Stays open on a hill Doesn’t kick back

GQ Huang (HKU)

FMEA-QFD-21


Easy to Open and Close

Window Secure from outside

Can be opened by owner only from outside

Easy to open from inside Easy to close from outside Easy to close from inside

Other issues like door


Isolation

No road noise No wind noise Doesn’t rattle Doesn’t let in rain Doesn’t leak in car wash Doesn’t drip in moisture when open


Arm Rest

Soft Comfortable Correct position


Easy Entrance and Exit

Convenient to enter and be seated Driver Passengers

Convenient to exit Child safety

Front Rear Windows

GQ Huang (HKU)

FMEA-QFD-22


Interior Trim

Material won’t fade Attractive Sturdy Stain resistant Warm in winter Cool in summer


Clean

Easy to clean No lubricant from door No dust from closure


Fit

Uniform gap between matching surfaces Appealing design


Customers-Who are They?

End users Service Assembly Suppliers Every step of the supply chain has CA’s Products should be easy to manufacture, assemble, service and

use

GQ Huang (HKU)

FMEA-QFD-23


CA Weights

Customer attributes (preferences) are normally not equally important. Add weights to show relative importance

CA’s may conflict! Easy to close door Quickly closing window

Heavier motor Weights allow CA’s to be prioritized.


The Competition?

How are we doing (or plan to do) relative to the competition? Market segmentation

East coast Mid-west West coast Economy luxury


Product Perceptual Map

Provides link between product concept and company’s strategic vision.


Engineering Characteristics-EC’s

Customers (marketing) tell us what to do. Engineering tells us how to do it. Let the design team list the EC’s that may affect the CA’s. Some EC’s may affect several CA’s. EC’s express how we plan to satisfy customer requirements (CA’S). EC’s should describe the product in measurable terms that directly affect CA’s.

GQ Huang (HKU)

FMEA-QFD-24


Creating the House of Quality


Relationship Matrix


Relationship Matrix

Shows the relationship between the CA’s and EC’s. Team reaches consensus on weights

or + indicates positive relationship X or – indicates negative relationship

After linking the voice of the customer (CA’s) to engineering actions (EC’s), the team adds objective measures (in engineering units) and targets below the house.


Relationship Matrix

GQ Huang (HKU)

FMEA-QFD-25


Roof Shows Trade-offs

Indicates a negative relationship between “energy to close door” and “door seal resistance”.


Trade-offs Must be Considered

Closures present a serious challenge Interaction is the rule not the exception!

Closing effort - door seal resistance - road noise

Door seal resistance + road noise

We must consider cost and technical feasibility.


Cost and Targets

Documents

FMEA - Product Development