Chap 10 Managing Engineering Design

D ecision Mak ing

P lanning

O rganizing

Leading

C ontro lling

Managem ent Functions

R esearch

D esign

Production

Q uality

Marketing

Project Managem ent

Managing Technology

Tim e Managem ent

E thics

C areer

Personal Technology

Managing Engineering and Technology

Advanced Organizer

Chapter Objectives

• Describe the phases or stages in systems engineering and the new product development process

• Recognize product liability and safety issues

• Recognize the significance of reliability and other design factors

Nature of Engineering Design

Eng. Design Process

Information: • Statement of the problem• Design standards• Design methods

Information: • Drawings• Specifications• Financial estimates• Written reports• Oral presentations

Systems Engineering/

New Product Development The design of a complex engineered system, from the realization of a need through production to engineering support in use is known as systems engineering (especially with military or space systems) or as new product development (with commercial systems).

New Product Development - Stages

• Conceptual • Technical Feasibility or Concept Definition• Development• Commercial Validation• Production• Product Support• Disposal Stage

Systems Engineering Process(In each phase of development)

• Requirements Analysis: Analyze customer needs, objectives, and constraints to determine the functional requirements.

• Functional Analysis/Allocation Identify lower level functions needed to meet these functional requirements, and translate them into design requirements suitable as design criteria.

• Synthesis. Define the system concept, configuration item alternatives and select the preferred set of product or process solutions to the level of detail required in the phase being conducted.

Systems Engineering Process(In each phase of development)

• System Analysis and Control. Provide the progress measurement, assessment, and decision mechanisms required to evaluate design capabilities and document the design and decision data. – Trade-off (trade) studies– Risk management– Configuration management– Interface management – Systems engineering master schedule (SEMS) – Technical performance measurement (TPM) – Technical (design) reviews

Quality Function Deployment (QFD)

• Quality function deployment is a team-based management tool in which the customer expectations are used to drive the product development process.

• Conflicting characteristics or requirements are identified early in the QFD process and can be resolved before production.

Quality Function Deployment (QFD)

Key benefits:

• product improvement,

• increased customer satisfaction,

• reduction in the total product development cycle, &

• increased market share.

Interrelationshipbetween

Technical Descriptors

How: Technical Descriptors(Voice of the Organization)

Relationship betweenRequirements and Descriptors

Prioritized Technical Descriptors

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QFD: House of Quality

4 Phases of QFD

Phase I:Productplanning

Phase II:Partsdeployment Phase III:

Processplanning

Phase IV:Productionplanning

Classical Model of QFD

Production Operations

Process Parameters

Process Design Matrix

Process Parameters

Piece/Part Characteristics

Piece/Part Design Matrix

Piece/Part Characteristics

Tech. Performance Measures

Subsystem Design Matrix

HowWhatMatrix

Voice of CustomerHouse of Quality

Tech. Performance Measures

Customer Needs •Good image•Easy to transport•Keeps present. flowing•Image visible in bad conditions•Minimizes unplanned interruptions•Design makes the product attractive•Device sets up quickly•Works well for short present.

PHASE I QFD -- Portable Slide ProjectorEngineering Metrics

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Good image 9 9 9Easy to transport 9 9 9Device sets up quickly 9 3 1 9 3 3Works well for short present. 9 1 3 3 3Keeps present. flowing 1 3 3 9Image visible in bad conditions 3 9 3Minimizes unplanned interruptions 1 3 1 9Design makes the product attractive 3 3 3 9

Raw score

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Relative Weight 1

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Engineering Metrics•Brightness•Weight•Dimensions (girth + width)•Time/Tasks required to start •Distortion•Distance from presenter •Time to insert/pull-out slide•Attractive product

QFD Example:Portable Slide Projector

QFD Example:Portable Slide Projector—

Phase I

Customer RequirementsGood image

Easy to transportDevice sets up quicklyWorks well for short present.Keeps present. flowingImage visible in bad conditionsMinimizes unplanned interruptionsDesign makes the product attractive

Cu

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Engineering Metrics

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Raw score

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QFD Example:Portable Slide Projector—

Phase IIPart Characteristics

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Engineering MetricsBrightnessWeight

Dimensions (girth + width)Time/Tasks required to start pres.

DistortionDistance from presenterTime to insert/pull-out slideAttractive product

Ph

ase I

R

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16%17%16%16%13%8%10%4%

9 9 1 99 9 1 1 39 9 3 9 1 3 3

3 39 9 1 19 9 9

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Raw score 3

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Rel. Weight 1

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Rank 3 4 2 1 7 6 5

Phases in Systems Engineering /

New Product Development (DoD)

• Pre-milestone zero studies• Concept exploration & definition• Demonstration and validation• Engineering and manufacturing

development• Production and deployment• Operations and support

Phases in Systems Engineering /

New Product Development (NASA)

• Conceptual design studies• Concept definition• Design and development• Fabrication, integration, test, and

certification• Pre-operations• Operations and disposal

Phases in Systems Engineering / New Product Development

(NSPE/NIST )

• Conceptual• Technical feasibility• Development• Commercial validation and production

preparation• Full-scale production• Product support

• Approval to expend the resources / agreement on the work to be accomplished.

• Accomplishment of the work • Compile the results: designs and

specifications, analyses and reports, and a proposed plan for conducting the following phase if one is recommended. – To cancel the development, – To go back (recycle) and do more work in the

present phase; or – To proceed with the next phase.

Tasks Within Each Phases of Systems Eng. / New Product

Development

Conceptual stage

• Statement of the design problem, clearly defining what the desired intended accomplishment of the desired product

• Key functions • Performance characteristics• Constraints • Criteria of judging the design quality

Conceptual stage

• Musts: requirements that must be met• Must nots: constraints defining what the

system must not be or do• Wants: features that would significantly

enhance the value of the solution but are not mandatory (to which an additional, even less compelling category of "nice to have" is often added)

• Don't wants: characteristics that reduce the value of the solution

Conceptual stage(Kano’s Model)

Actual Performanc

e

Customer Satisfaction

SatisfiersDissatisfiers

Delighters

Conceptual stage(Kano’s Model)

Product is non-conformantProduct conforms to std.

Product is unsafeProduct is safe to use

Function not providedNormal function

Missing instructionClear instruction

Broken partsAll parts work

Scratches, blemishesSmooth Surface

DissatisfiersExpected Quality

Conceptual stage (Kano’s Model)

LargerTBTransactions /secondSpeed

LargerTBMTBFReliability

SmallerTBDollarsPrice

LargerTBCubic feet of storageCapacity

Direction

Performance Measure

Desired Quality

Satisfiers:

Conceptual stage(Kano’s Model)

Examples of Delighters• Sony Walkman• 3M Post-it• Cup Holder• One-touch recording• Redial button on telephone• Graphic User Interface (GUI)

Results from Conceptual stage

• A set of functional requirements• Identification of the potential barriers to

development, manufacturing, and marketing the proposed product.

• Test-of-principle model to reduce technical uncertainties

• Order-of-magnitude economic analyses and • Preliminary market surveys to reduce

financial uncertainty.

Importance of Conceptual stage

• 1% of the cost of the product• 70 % of the life-cycle cost

Technical feasibility stage

The objectives of this stage are • To confirm the target performance of the

new product through experimentation and/or accepted engineering analysis and

• To ascertain that there are no technical or economic barriers to implementation

Technical feasibility stage

• Subsystem identification• Trade-off studies• System integration• Interface definition• Preliminary breadboard-level testing • Subsystem and system design requirements (reliability,

safety, maintainability, and environmental impact).• Development of preliminary test plans, production

methods, maintenance and logistic concepts, and marketing plans.

• Preliminary estimation of the life-cycle cost of the system.

• Preparation of a proposal for the development stage

Importance of Technical feasibility stage

• 7% of the cost of the product• 85 % of the life-cycle cost

Development stage (Build-test-fix-retest

sequences)The objective of this stage is • To make the needed improvements in

materials, designs and processes and • To confirm that the product will perform as

specified by constructing and testing engineering prototypes or pilot processes.

Commercial validation and Production preparation stage

The objective of this stage is to develop the manufacturing techniques and establish test market validity of the new product.

• Selecting manufacturing procedures, production tools and technology, installation and start-up plans for the manufacturing process, and

• Selecting vendors for purchased materials, components, and subsystems.

Reproduction prototypes

Full-scale production stage

• Final design drawings, specifications, flow charts, and procedures are completed for manufacture and assembly of all components and subsystems of the product, as well as for the production facility.

• Quality control procedures and reliability standards are established

• Contracts made with suppliers• Procedures established for product distribution and

support. • Manufacturing facilities are constructed• Continuous process improvement (kaizen)

Product support stage

• Technical manuals for product installation, operation, and maintenance

• Training programs for customer personnel• Technical supports• Warranty services• Repair parts and replacement consumables must

be manufactured and distributed• New procedures for operation and maintenance• Improved parts for retrofit• Notification of product recall for safety reasons

Disposal stage

• Every product causes waste during manufacture, while in use, and at the end of useful life that can create disposal problems.

• The time to begin asking, "how do we get rid of this" is in the early stages of product or process design.

CONCURRENT ENGINEERING AND

CALS

Traditional Product Development

• System Level Design• Subsystem Design• Component Design• Manufacturing Process Concept Development• Manufacturing Process Development• Delivery Development• Service Development• Delivery

Concurrent Processes

System Level Design

Manufacturing Process Concept

Development

Delivery Development

Production & Delivery

Component Design

Subsystem Design Manufacturing

Process Development

Service Development

Definition of Concurrent Engineering

A systematic approach to the integrated, concurrent design of products and their related processes, including manufacture and support.

This approach is intended to cause the developer, from the outset, to consider all elements of the product lifecycle from concept through disposal, including quality control, cost, scheduling, user requirements. (Inst. For Defense Analysis)

Advantages of Concurrent Engineering

The set of methods, techniques, and practices that:• Cause significant consideration within the design

phases of factors from later in the life cycle;• Produce, along with the product design, the design

of processes to be employed later in the life of the product;

• Facilitate the reduction of the time required to translate the design into distributed products; and

• Enhance the ability of products to satisfy users' expectations and needs.

CALS

• "Computer Aided Logistics Support," then • "Computer-aided Acquisition and Logistics

Support," • "Continuous Acquisition and Life-Cycle Support,"

(1993, DoD)• "Commerce At Light Speed" (U.S. industry)

Purposes of CALS

To enable more effective generation, management, and use of digital data supporting the life cycle of a product through the use of international standards, business process change, and advanced technology application.

CALS

Electronic storage, transmission, and retrieval of digital data

• Between engineers representing the several design stages,

• Between organization functions such as marketing, design, manufacturing, and product support, and

• Between cooperating organizations such as customer and supplier.

Commercial standards

• Computer Graphics Metafile (CGM) (ISO-8632): A standard means of representing line drawings in a device-independent way.

• Electronic Data Interchange for Administration, Commerce, and Transport (EDIFACT) (ISO 9735, ANSI X12): An international standard means for communicating commercial (trade) information.

• Initial Graphics Exchange Specification (IGES) (ANSI Y14.26M): A standard means of representing product data in a device-independent way.

Control Systems in Design

• Drawing/Design Release– Version Control– Product Data Management (PDM)

• Configuration (Design Criteria) Management– Functional baseline (at end of conceptual stage)– Allocated baseline (at end of validation stage)– Product baseline (at end of development stage)

• Design Review

Special Considerations in Design

• Product liability • Safety• Reliability• Maintainability• Availability• Ergonomics• Producibility

History of Product Liability

• Caveat emptor (let the buyer beware)• “Privity of contract” (Direct contractual relationship)• 1916, MacPherson v. Buick (No need for direct contract)• Plaintiff must prove negligence• 1960, Hernington v. Bloomfield Motors, implied

warranty• 1984, Greenman v. Yuba Power Product Strict

Liability• Absolute liability: “A manufacturer could be held strictly

liable for failure to warn of a product hazard, even if the hazard was scientifically unknowable at the time of the manufacture and sale of the product.”

Reducing Liability

• Include safety as a primary specification for product design.

• Use standard, proven materials and components. • Subject the design to thorough analysis and testing.• Employ a formal design review process in which

safety is emphasized.• Specify proven manufacturing methods.• Assure an effective, independent quality control

and inspection process.• Be sure that there are warning labels on the

product where necessary.

Reducing Liability

• Supply clear and unambiguous instructions for installation and use.

• Establish a traceable system of distribution, with warranty cards, against the possibility of product recall.

• Institute an effective failure reporting and analysis system, with timely redesign and retrofit as appropriate.

• Document all product safety precautions, actions, and decisions through the product life cycle.

Designing for Reliability

Definition of Reliability:

• Reliability is the probability that a system

• Will demonstrate specified performance

• For a stated period of time

• When operated under specified conditions.

Reliability Measures

• Reliability

0

tt S

SR

• Failure CDF (cumulative distribution function):

• Failure PDF (probability density function):

• Failure or hazard rate:

t

0 0S

FF(t)

0

t

S

Ff(t)

t

t

S

F(t)

Simple Reliability Models

• Simple Parallel Model

)R)(R(R LST

S L

L

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• Simple Series Model

2LT )R1(1R

Simple Reliability Models

2L

2ST )R1(1)R1(1R

L

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S

L

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• Series- parallel model

2LST )R)(R(11R

Infant Mortality

Useful Life Wear-out

Hazard Rate

Life

Simple Reliability ModelsBathtub curve

Designing for Reliability

• “Start with the best”

• Redundancy

• Factor of safety

Maintainability

• Maintainability is the probability that a failed system

• Will be restored to specified performance

• Within a stated period of time

• When maintained under specified conditions.

Maintainability

Maintenance downtime• Administrative & preparation time• Logistic time• Active maintenance time

Types of Maintenance • Corrective maintenance• Preventive maintenance• Predictive maintenance

Availability

• Inherent Availability (considers only corrective maintenance)

Ai = MTBF / (MTBF+MTTR)• Operational Availability (considers both preventive

& corrective maintenance)

Ao = MTBM / (MTBM+MDT)MTBM: Mean Time Between MaintenanceMDT: Mean Down TimeMTTR: Mean Time To RepairMTBF: Mean Time Between Failure (1/)BIT: Build-In Test

Other Considerations

• Human Factors Engineering (Ergonomics)• Standardization

– Set of specifications for parts, materials, or processes intended to achieve uniformity, efficiency, and a specified quality.

• Producibility

Value Engineering

A methodical study of all components of a product in order to discover and eliminate unnecessary costs over the product life cycle without interfering with the effectiveness of the product.

• What is it?• What does it do?• What does it cost?• What does it worth?• What else might do the job?• What do the alternatives cost?• Which alternative is least expensive?• Will the alternative meet the requirements?• What is needed to implement the alternative?