Senior DesignSenior Design

Fall 2005, Week 3Fall 2005, Week 3

Notes are based on “Engineering Notes are based on “Engineering Design and Design for Design and Design for Manufacturing – A Structured Manufacturing – A Structured Approach” by John R. Dixon and Approach” by John R. Dixon and Corrado PoliCorrado Poli

Lecture OverviewLecture Overview

GroupsGroups ProjectsProjects Conceptual Design OverviewConceptual Design Overview Formulating the problemFormulating the problem

– Customer AttributesCustomer Attributes– Engineering CharacteristicsEngineering Characteristics– Engineering Design SpecificationEngineering Design Specification

GroupsGroups

Group 1 (Energy 1 – project presented by Group 1 (Energy 1 – project presented by Dr. Fletcher)Dr. Fletcher)

Richelle AtienzaRichelle Atienza Holman ChuaHolman Chua Jason GarnerJason Garner Jason HarringtonJason Harrington Joshua SeveranceJoshua Severance

Group 2 (ASME 1)Group 2 (ASME 1) William BerryWilliam Berry Nicholas FonderNicholas Fonder Jason KardosJason Kardos James MartiniJames Martini

Group 3 (Energy 2 – project to be Group 3 (Energy 2 – project to be discussed with Dr. Fletcher)discussed with Dr. Fletcher)

Sean MochockiSean Mochocki Evan McNayEvan McNay Lince PhilipLince Philip Richard ThompsonRichard Thompson Stephen ThompsonStephen Thompson

Group 4 (ASME 2)Group 4 (ASME 2) Justin CaudleJustin Caudle Luke DelaneyLuke Delaney Joshua IsaacsonJoshua Isaacson Peter VergenzPeter Vergenz

Group 5 (Extruder – Project presented by Group 5 (Extruder – Project presented by Dr. Adewale or a modification to the Dr. Adewale or a modification to the project)project)

Anthony BarlettaAnthony Barletta Daniel JonesDaniel Jones Parineeta NayyarParineeta Nayyar Spencer SchwabSpencer Schwab

Engineering Engineering Conceptual DesignConceptual Design The GoalThe Goal

– Determine the physical concept of the designed Determine the physical concept of the designed objectobject

Information about the physical principles by which Information about the physical principles by which the object will achieve its principal functionsthe object will achieve its principal functions

An abstract physical description of the object called An abstract physical description of the object called the the embodimentembodiment

– Embodiment: Abstract physical description with few Embodiment: Abstract physical description with few details provideddetails provided

Beam is long and slender member of uniform cross Beam is long and slender member of uniform cross section but we don’t know the exact cross sectional section but we don’t know the exact cross sectional shape or dimensionsshape or dimensions

The process of decompositionThe process of decomposition Guided IterationGuided Iteration

The process of The process of decompositiondecomposition It is necessary to “decompose” the design into It is necessary to “decompose” the design into

more manageable more manageable sub-assemblies/components.sub-assemblies/components.

Helps in finding creative solutions and Helps in finding creative solutions and ultimately generating a superior design ultimately generating a superior design

Two primary approaches of conceptual Two primary approaches of conceptual decomposition are useddecomposition are used– Direct decompositionDirect decomposition– Function-First decompositionFunction-First decomposition

Will need to include the couplings between Will need to include the couplings between subsystemssubsystems– How are forces transferred? Energy transfer?How are forces transferred? Energy transfer?

Direct DecompositionDirect Decomposition

A product is composed of the A product is composed of the subsidiary components (the design is subsidiary components (the design is not really decomposed)not really decomposed)

Ex: An automobile is decomposed into Ex: An automobile is decomposed into its engine, drive train, body, its engine, drive train, body, suspension system, steering system.suspension system, steering system.

Then you work on each of the Then you work on each of the decomposed systems and find the best decomposed systems and find the best design for each.design for each.

This decomposition method minimizes This decomposition method minimizes creative new ideas.creative new ideas.

Direct Decomposition Direct Decomposition continuedcontinued Often used by Mechanical EngineersOften used by Mechanical Engineers A sketch is commonly used identifying A sketch is commonly used identifying

the embodimentthe embodiment Ex: For a bicycle we would identify the Ex: For a bicycle we would identify the

handle bar (but for what function)handle bar (but for what function) Ex: Design a breaking system for an Ex: Design a breaking system for an

automobileautomobile– Foot pedal, hydraulic system, and brake Foot pedal, hydraulic system, and brake

shoes and drums.shoes and drums.

Function-First Function-First DecompositionDecomposition First the functions are identified First the functions are identified

without any embodiments without any embodiments assumedassumed

Then embodiments are identified Then embodiments are identified to fulfill the functional needsto fulfill the functional needs

This process often helps identify This process often helps identify creative solutionscreative solutions

Abstract way of thinking. Abstract way of thinking.

Overview of Guided Iteration Overview of Guided Iteration Applied to Engineering Applied to Engineering Conceptual DesignConceptual Design Formulating the Engineering Conceptual Deisgn Problem: The Engineering Formulating the Engineering Conceptual Deisgn Problem: The Engineering

Design SpecificationDesign Specification– The Engineering Design Specification is used during the conceptual design stage and The Engineering Design Specification is used during the conceptual design stage and

through the rest of the design stages.through the rest of the design stages.– Should be a written documentShould be a written document– Convert the vague, qualitative, and incomplete information that is generally available Convert the vague, qualitative, and incomplete information that is generally available

at the beginning of the conceptual design stage into a set of specific, quantitative, at the beginning of the conceptual design stage into a set of specific, quantitative, complete performance requirementscomplete performance requirements

Will use Quality Function Deployment (more to come…)Will use Quality Function Deployment (more to come…) Ex: Should be easy to carry Ex: Should be easy to carry the weight should be less than 20lb the weight should be less than 20lb

Generating Alternatives in Engineering Conceptual Design ProblemsGenerating Alternatives in Engineering Conceptual Design Problems– The selection of the best possible conceptual design is crucial in obtaining the best The selection of the best possible conceptual design is crucial in obtaining the best

possible final design solution.possible final design solution.– Mistakes at the conceptual design stage are extremely costly if you must backtrack Mistakes at the conceptual design stage are extremely costly if you must backtrack

when in the configuration, parametric, and detailed design stages.when in the configuration, parametric, and detailed design stages. Evaluating Alternatives in Engineering Conceptual DesignEvaluating Alternatives in Engineering Conceptual Design

– Alternatives are rated and comparedAlternatives are rated and compared Guided Redesign Guided Redesign

– Illuminate the specific characteristics of proposed alternatives that are weak and Illuminate the specific characteristics of proposed alternatives that are weak and strong.strong.

– Is the design “good-enough”?Is the design “good-enough”?

Summary of guided iteration Summary of guided iteration methods (Engineering Conceptual methods (Engineering Conceptual Design)Design)Steps in GI processSteps in GI process MethodsMethods

Problem formulationProblem formulation Quality Function Deployment Quality Function Deployment and House of Quality and House of Quality Engineering Design Engineering Design SpecificationSpecification

Generation of AlternativesGeneration of Alternatives Search for alternatives physical Search for alternatives physical laws and effectslaws and effectsTechniques for creativityTechniques for creativityMemory SearchMemory SearchAnalogous ProblemsAnalogous ProblemsLiterature searchesLiterature searches

Evaluation of alternativesEvaluation of alternatives Pugh’s methodPugh’s methodDominic’s MethodDominic’s MethodPahl and Beitz MethodPahl and Beitz Method

Redesign, Guided by the Redesign, Guided by the evaluation and physical evaluation and physical reasoningreasoning

Modify Existing AlternativesModify Existing AlternativesNew alternativesNew alternatives

Formulating the Problem: Formulating the Problem: The Engineering Design The Engineering Design SpecificationSpecification

Includes statementsIncludes statements– In-use purposes, andIn-use purposes, and– Functional requirementsFunctional requirements

Some information may be available from Some information may be available from marketing and industrial design stagemarketing and industrial design stage

Most information available at this stage is Most information available at this stage is typically qualitative, incomplete, and/or typically qualitative, incomplete, and/or approximateapproximate

The Engineering Design Specification will be The Engineering Design Specification will be used in future design stages so care should be used in future design stages so care should be put into making it as detailed and complete as put into making it as detailed and complete as possible.possible.

Overview: Engineering Overview: Engineering Design Specification Design Specification (Specs)(Specs) in-use purposes in-use purposes

– Primary PurposePrimary Purpose– Unintended PurposeUnintended Purpose– Special PurposeSpecial Purpose

Functional RequirementsFunctional Requirements– Product performancesProduct performances

Functional Performance RequirementsFunctional Performance Requirements Complementary PerformanceComplementary Performance

– Environmental and other conditionsEnvironmental and other conditions– Economic issuesEconomic issues– Physical attributesPhysical attributes– Process technologiesProcess technologies– AestheticsAesthetics– Product development time and costProduct development time and cost

Before developing the Specs it is best to understand the customer Before developing the Specs it is best to understand the customer needs.needs.

– House of Quality House of Quality

Quality Function Quality Function Deployment (QFD) and Deployment (QFD) and the House of Quality the House of Quality (HoQ)(HoQ) QFD: term used to describe a QFD: term used to describe a

strategy for focusing engineering strategy for focusing engineering design attention on quality issues design attention on quality issues as perceived by customersas perceived by customers

HoQ: A technique used for HoQ: A technique used for structuring information commonly structuring information commonly used to implement QFD.used to implement QFD.

House of QualityHouse of Quality

Matrix that relates the customers wants (Customer Matrix that relates the customers wants (Customer Attributes) to the technical product characteristics Attributes) to the technical product characteristics (Engineering Characteristics)(Engineering Characteristics)

Customer Attributes (CA)Customer Attributes (CA)– Generally qualitativeGenerally qualitative

Fast, smooth, easyFast, smooth, easy– The Customer Attributes are listed to the left of the rows The Customer Attributes are listed to the left of the rows

(also grouped – functions, features)(also grouped – functions, features)

Engineering Characteristics (EC)Engineering Characteristics (EC)– QualitativeQualitative

Weight in poundsWeight in pounds– The Engineering Characteristics are listed at the top of The Engineering Characteristics are listed at the top of

the columns (grouped by categories)the columns (grouped by categories) HoQ is also used for competitive benchmarkingHoQ is also used for competitive benchmarking

House of QualityHouse of Quality

Coffee Maker ExampleCoffee Maker Example

Customer Attributes Customer Attributes Good coffee Good coffee– Nice looking coffee makerNice looking coffee maker– Easy to cleanEasy to clean

Engineering CharacteristicsEngineering Characteristics– Goodness of coffee (in measurable quantities)Goodness of coffee (in measurable quantities)

Functional requirementsFunctional requirements– Temperature Temperature – Flow rate of waterFlow rate of water– Time the water takes to flow through the groundsTime the water takes to flow through the grounds– Temperature when poured into the cupTemperature when poured into the cup

EC will include requirements such as the electrical resistance to the EC will include requirements such as the electrical resistance to the heater, the size of the tube supplying the hot water to the coffee heater, the size of the tube supplying the hot water to the coffee grounds, and other factors having to do with geometry and grounds, and other factors having to do with geometry and materials.materials.

Since there are yet no proposed designs there are no engineering Since there are yet no proposed designs there are no engineering characteristics yet.characteristics yet.

Determine the Customer Attributes, then write the Specs Determine the Customer Attributes, then write the Specs and then return to the Engineering Characteristicsand then return to the Engineering Characteristics

CD protective portable CD protective portable carrying casecarrying case Customer AttributesCustomer Attributes

– Protects the discsProtects the discs– Attractive Attractive – InexpensiveInexpensive– Can identify the contentsCan identify the contents– Stays closedStays closed– Easy to openEasy to open– Can’t be used as a coaster Can’t be used as a coaster

for coffee cupsfor coffee cups– Holds at least 6 CDsHolds at least 6 CDs– Doesn’t pop open on its Doesn’t pop open on its

ownown– Won’t break if droppedWon’t break if dropped– CompactCompact

Eliminate redundanciesEliminate redundancies Organize the list Organize the list

hierarchicallyhierarchically– Protects the discsProtects the discs

Stays closedStays closed Won’t break if droppedWon’t break if dropped Can’t be used as a coaster Can’t be used as a coaster

for coffee cupsfor coffee cups– Convenient to useConvenient to use

Easy to OpenEasy to Open Ca identify the contentsCa identify the contents CompactCompact

– AttractiveAttractive– Holds at least six CDsHolds at least six CDs– InexpensiveInexpensive

Often priorities are assigned Often priorities are assigned to the customer attributes to the customer attributes that total 100 unitsthat total 100 units

Assignment of Assignment of prioritiespriorities

– Stays closedStays closed 2020– Won’t break if droppedWon’t break if dropped 1414– Can’t be used as a coaster for coffee cupsCan’t be used as a coaster for coffee cups 5 5– Easy to OpenEasy to Open 2020– Can identify the contentsCan identify the contents 1010– CompactCompact 77– AttractiveAttractive 55– Holds at least six CDsHolds at least six CDs 77– InexpensiveInexpensive 1010

TotalTotal 100100

Content of the Content of the Engineering Design Engineering Design SpecificationSpecification Develop the Specs after the Develop the Specs after the

Customer Attributes have been Customer Attributes have been identifiedidentified

The Specs should includeThe Specs should include– In-use purposesIn-use purposes– Functional RequirementsFunctional Requirements

In-use purposesIn-use purposes

Primary Intended Use By CustomersPrimary Intended Use By Customers– ExamplesExamples

To make coffeeTo make coffee To convert electrical to rotating energyTo convert electrical to rotating energy To aid in the catching of a baseball and to protect the hand when To aid in the catching of a baseball and to protect the hand when

doing sodoing so– Some products have multiple usesSome products have multiple uses

Baseball glove exampleBaseball glove example Hammer: Drive and pull nailsHammer: Drive and pull nails

Predictable Unintended UsesPredictable Unintended Uses– Wrenches are used as hammersWrenches are used as hammers– Screw drivers as chiselsScrew drivers as chisels– Shelves and chairs as step laddersShelves and chairs as step ladders– People standing (and jumping) on top of the washing machinePeople standing (and jumping) on top of the washing machine– People driving with the windshield sun protector???? Remove People driving with the windshield sun protector???? Remove

when driving. UNF parking tag….when driving. UNF parking tag….– NOT enough to use warnings. NOT enough to use warnings. Must design with unintended Must design with unintended

uses in mind. Legal and common sense reasons.uses in mind. Legal and common sense reasons. Design the wrench such that it is reasonable safe to use as a Design the wrench such that it is reasonable safe to use as a

hammerhammer

In-use purposesIn-use purposes

Special Purpose FeaturesSpecial Purpose Features– Features that enhance the productFeatures that enhance the product

Rechargeable electric shaver that can be Rechargeable electric shaver that can be directly plugged into the outlet rather directly plugged into the outlet rather than having an inconvenient cord.than having an inconvenient cord.

Redial button on your telephoneRedial button on your telephone No-drip tops on laundry detergentsNo-drip tops on laundry detergents

– May rate the special purpose features May rate the special purpose features as essential, important, or desirableas essential, important, or desirable

Functional Functional RequirementsRequirements Product performancesProduct performances

– Functional Performance RequirementsFunctional Performance Requirements Capacity (energy or material flow rate, force, …)Capacity (energy or material flow rate, force, …) Input and output conditions (temperature, energy, Input and output conditions (temperature, energy,

pressures, flows, power, deflections, forces)pressures, flows, power, deflections, forces) EfficiencyEfficiency Accuracy and sensitivityAccuracy and sensitivity

– Complementary PerformanceComplementary Performance Useful lifeUseful life ReliabilityReliability RobustnessRobustness SafetySafety NoiseNoise Legal requirementsLegal requirements Maintenance requirementsMaintenance requirements Requirements on users (skills, speed, knowledge, …)Requirements on users (skills, speed, knowledge, …)

Functional Functional Requirements Requirements ContinuedContinued Environmental and other conditionsEnvironmental and other conditions

– Temperature, humidity, corrosive elements, noise, dirt, Temperature, humidity, corrosive elements, noise, dirt, vibration, electric or magnetic field.vibration, electric or magnetic field.

– Extremes of variationsExtremes of variations– How product will be disposed, how it will influence the How product will be disposed, how it will influence the

environment, design for dis-assembly.environment, design for dis-assembly.– Is pollution a problem?Is pollution a problem?

Economic issuesEconomic issues– Tooling cost, initial product cost, maintenance costs, return on Tooling cost, initial product cost, maintenance costs, return on

investment, cash flow, break even timeinvestment, cash flow, break even time Physical attributesPhysical attributes

– Weight, size, shape, surface finish, …Weight, size, shape, surface finish, … AestheticsAesthetics

– Style, uniqueness, …Style, uniqueness, …– Work with marketing teamWork with marketing team

Product development time and costProduct development time and cost Process technologiesProcess technologies

– restrictions on manufacturing processesrestrictions on manufacturing processes

Expressing Functional Expressing Functional RequirementsRequirements QualitativelyQualitatively

– Verbal statement (high, low, moderate, fast, slow, Verbal statement (high, low, moderate, fast, slow, …)…)

As extremum goals, with or without limitsAs extremum goals, with or without limits– Mass should be as low as possibleMass should be as low as possible– Mass should be as low as possible but no higher Mass should be as low as possible but no higher

than 10 lbthan 10 lb As target values with toleranceAs target values with tolerance

– The power output of an engine should be 5 Hp +/- The power output of an engine should be 5 Hp +/- 0.25 Hp0.25 Hp

As rangesAs ranges– Length must be between 3.7 and 4.8 inchesLength must be between 3.7 and 4.8 inches

Completeness and Completeness and Invariability of the Invariability of the Engineering DesignEngineering Design The Specs should never be though of The Specs should never be though of

as complete or invariable at any as complete or invariable at any stage in the design process.stage in the design process.

Specifications should be Specifications should be as as complete as possible complete as possible on on what the what the designed object is to dodesigned object is to do. They . They should should say as little as possible say as little as possible about about how the requirements are to how the requirements are to be met.be met.

Example: A Portable Example: A Portable Wind Chill MeterWind Chill Meter In-purpose useIn-purpose use

– Primary Intended UsePrimary Intended Use For skiers and winter hikers: to be able to For skiers and winter hikers: to be able to

determine the so-called “wind chill” factor easily determine the so-called “wind chill” factor easily and convenientlyand conveniently

– Unintended Uses:Unintended Uses: Non anticipatedNon anticipated

– Special FeaturesSpecial Features Indicate temperature, wind velocity seperately Indicate temperature, wind velocity seperately

as well as the combined wind chillas well as the combined wind chill

Example continuedExample continued

Functional requirementsFunctional requirements– Performance requirementsPerformance requirements

Functional Performance requirementsFunctional Performance requirements– Indicated reading should be accurate within one Indicated reading should be accurate within one

degree using U.S. Weather Bureau formula for degree using U.S. Weather Bureau formula for the wind chillthe wind chill

– The meter should provide a reading after no more The meter should provide a reading after no more than 20 seconds for reaching equilibrium with the than 20 seconds for reaching equilibrium with the outdoor environmentoutdoor environment

– The meter should perform with the above The meter should perform with the above accuracy from 32 F to 50 F, and from wind accuracy from 32 F to 50 F, and from wind velocities from 10 mph to 60 mph. Accuracy velocities from 10 mph to 60 mph. Accuracy should not be affected by mis-orientation with the should not be affected by mis-orientation with the wind direction up to 20 degree anglewind direction up to 20 degree angle

Example continuedExample continued

Functional requirementsFunctional requirements– Performance requirementsPerformance requirements

Complementary performance requirements:Complementary performance requirements:– The expected life in normal use should be at least The expected life in normal use should be at least

10 years10 years– The reliability should be such that no more than The reliability should be such that no more than

one in 1000 sold will be returned for repairs or one in 1000 sold will be returned for repairs or replacement during the 1replacement during the 1stst year of use. year of use.

– Must be able to withstand shocks and pressure Must be able to withstand shocks and pressure without damage when carried in jacket pocketswithout damage when carried in jacket pockets

– Hiker or skier should not be cut by the device if Hiker or skier should not be cut by the device if (s)he falls.(s)he falls.

– No maintenance should be required (except No maintenance should be required (except battery replacement – if used)battery replacement – if used)

Example continuedExample continued

Environmental conditionsEnvironmental conditions– Use at previously mentioned conditionsUse at previously mentioned conditions– Survive summer shipping storage up to Survive summer shipping storage up to

120 F and 80% humidity120 F and 80% humidity Economic issuesEconomic issues

– $10 (for a volume of 5000)$10 (for a volume of 5000) Physical AttributesPhysical Attributes

– To be carried in a ski or hiking jacket To be carried in a ski or hiking jacket pocketpocket

– No more than 16 ozNo more than 16 oz– 3 x 5 x ¾ in3 x 5 x ¾ in33

Example continuedExample continued

Process TechnologiesProcess Technologies– NoneNone

AestheticsAesthetics– Should look like a rugged, reliable, accurate device Should look like a rugged, reliable, accurate device

compatible with the quality equipment needed by compatible with the quality equipment needed by skiers and hikersskiers and hikers

Product development time and costProduct development time and cost– The product should be designed and prototyped by The product should be designed and prototyped by

<specific date>. Design and development cost, <specific date>. Design and development cost, including engineering , model shop, and laboratory including engineering , model shop, and laboratory should not exceed <specified amount>should not exceed <specified amount>

Assignment for next Assignment for next weekweek Meet with your groupMeet with your group

– Define a project leaderDefine a project leader– Determine times when you will work on Determine times when you will work on

the project as a groups each weekthe project as a groups each week At least 2 times (Beginning of the week At least 2 times (Beginning of the week

discuss the tasks, split and work discuss the tasks, split and work independently, regroup)independently, regroup)

Define the Customer Attributes with Define the Customer Attributes with prioritiespriorities

Start discussing the SpecsStart discussing the Specs