Chap 10 Managing Engineering Design. Advanced Organizer.
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Transcript of Chap 10 Managing Engineering Design. Advanced Organizer.
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 processRecognize product liability and safety issuesRecognize 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 DefinitionDevelopmentCommercial ValidationProductionProduct SupportDisposal 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.
Quality Function Deployment (QFD)Identify User Needs & Wants
Gather raw data– Interviews– Focus Groups– Observation
Interpret raw data– Affinity Diagram– Needs Statements
Organize needs & establish importance – Surveys– Conjoint Analysis
Quality Function Deployment (QFD)
Identify User Needs & WantsGather raw data (Interview Segmentation)
UnhappyCustomers
HappyCustomers
Never TriedProduct
PreferCompetitors
LeadUsers
Male
Female
Children
Tra
dit
ion
al D
em
ogra
ph
ic
Segm
en
tati
on
Non-Traditional Segmentation
Quality Function Deployment (QFD)Identify User Needs & Wants
Gather raw data (How many interviews are needed? )
Number of Custom ers Interview ed
0%
20%
40%
60%
80%
100%
5 10 15 20 25 30
Percent of NeedsIdentified
G riffin & H auser 1993
Quality Function Deployment (QFD)Identify User Needs & Wants
Gather raw data (Focus Groups)
From: Griffin, Abbie and John R. Hauser. “The Voice of the Customer”, Marketing Science. vol. 12, no. 1, Winter 1993.
One-on-One Interviews (1 hour)
Focus Groups (2 hours)
0 1 2 3 4 5 6 7 8 9 10
0
20
40
60
80
100
Per
cen
t o
f N
eed
s Id
enti
fied
Number of Respondents or Groups
Quality Function Deployment (QFD)Identify User Needs & Wants
Interpret raw data– Affinity Diagram
Organizes subjective information Example: Group the following CR’s
• “ease of handling”• “portability” • “number readability” • “load handling”• “ease of use”
Quality Function Deployment (QFD)
Identify User Needs & WantsInterpret raw data (Needs Statements)– What, not How– Be specific– Positive, not negative– Attributes of the product– Avoid “must” or “should”.
House of Quality
Interrelationshipbetween
Technical Descriptors
Technical Descriptors(Voice of the Organization)
Relationship betweenRequirements and Descriptors
Prioritized Technical Descriptors
Pri
oriti
zed
Cus
tom
er
Req
uire
men
ts
Cus
tom
er
Req
uire
men
ts (Voi
ce o
f th
e C
usto
mer
)Interrelationship
betweenTechnical Descriptors
Technical Descriptors(Voice of the Organization)
Relationship betweenRequirements and Descriptors
Prioritized Technical Descriptors
Pri
oriti
zed
Cus
tom
er
Req
mts
Cus
tom
er
Req
mts
(Voi
ce o
f th
e C
usto
mer
)
4 Phases of QFD
Classical Model of QFDMatrix What How
House of Quality
Voice of Customer
Tech. Performance
Measures
Subsystem Design Matrix
Tech. Performance
Measures
Piece/Part Characteristics
Piece/Part Design Matrix
Piece/Part Characteristics
Process Parameters
Process Design Matrix
Process Parameters
Production Operations
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
Customer Requirements Cu
sto
mer
Weig
hts
Bri
gh
tness
Weig
ht
Dim
en
sion
s (g
irth
+ w
idth
)
Tim
e/T
ask
s re
qu
ired
to s
tart
pre
sen
tati
on
Dis
tort
ion
Dis
tan
ce f
rom
pre
sen
ter
(wit
h 3
' x 3
' p
roje
cti
on
)
Tim
e t
o i
nse
rt/p
ull
-ou
t sl
ide
Att
racti
ve p
rod
uct
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
10
8
11
7
10
8
11
4
90
58
72
27
Relative Weight 1
6%
17
%
16
%
16
%
13
%
8%
10
%
4%
Engineering Metrics•Brightness•Weight•Dimensions (girth + width)•Time/Tasks required to start present.•Distortion•Distance from presenter •Time to insert/pull-out slide•Attractive product
Portable Slide Projector
Example
QFD Matrix Example
Engineering Metrics
Customer Requirements Cus
tom
er W
eigh
ts
Brig
htne
ss
Wei
ght
Dim
ension
s (g
irth
+ w
idth
)
Tim
e/Tas
ks req
uire
d to
sta
rt p
rese
ntat
ion
Disto
rtio
n
Dista
nce
from
pre
sent
er (w
ith
3' x
3' p
roje
ctio
n)
Tim
e to
inse
rt/p
ull-ou
t slid
e
Attra
ctiv
e pr
oduc
t
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 9Minimizes unplanned interruptions 1 3 1 9Design makes the product attractive 3 3 3 9
Raw score
108
117
108
114
81 58 72 27
Relative Weight 16
%
17%
16%
17%
12%
8% 11%
4%
Phase I -
Portable Slide Projector
Part Characteristics
Engineering Metrics Ph
ase
I R
ela
tive
Weig
hts
Top c
ase
Bott
om
case
Lens
Condense
rS
tand
Heat
sink
Lam
p
Brightness 16% 9 9 1 9Weight 17% 9 9 1 1 3Dimensions (girth + width) 16% 9 9 3 9 1 3 3Time/ Tasks required to start presentation 16% 3 3Distortion 13% 9 9 1 1Distance from presenter (with 3' x 3' projection) 8% 9 9 9Time to insert/ pull-out slide 10% 3 1Attractive product 4% 9 9 9
Raw score 3
.6
3.3
4.4
4.9
1.1
1.3
2.7
Rel. Weight 1
7%
15%
21%
23%
5%
6%
13%
Rank 3 4 2 1 7 6 5
Phase II -
Portable Slide Projector
Phases in Systems Engineering / New Product Development
(DoD)
Pre-milestone zero studiesConcept exploration & definitionDemonstration and validationEngineering and manufacturing developmentProduction and deploymentOperations and support
Phases in Systems Engineering / New Product Development
(NASA)
Conceptual design studiesConcept definitionDesign and developmentFabrication, integration, test, and certificationPre-operationsOperations and disposal
Phases in Systems Engineering / New Product Development
(NSPE/NIST )ConceptualTechnical feasibilityDevelopmentCommercial validation and production preparationFull-scale productionProduct 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 productKey functions Performance characteristicsConstraints Criteria of judging the design quality
Conceptual stage
Musts: requirements that must be metMust nots: constraints defining what the system must not be or doWants: 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
Satisfiers
Dissatisfiers
Delighters
Conceptual stage (Kano’s
Model) Expected Quality Dissatisfiers
Smooth Surface Scratches, blemishes
All parts work Broken parts
Clear instruction Missing instruction
Normal function Function not provided
Product is safe to use Product is unsafe
Product conforms to std.
Product is non-conformant
Conceptual stage (Kano’s
Model)
Desired Quality
Performance Measure
Direction
Capacity Cubic feet of storage
LargerTB
Price Dollars SmallerTB
Reliability MTBF LargerTB
Speed Transactions /second
LargerTB
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 requirementsIdentification of the potential barriers to development, manufacturing, and marketing the proposed product.Test-of-principle model to reduce technical uncertaintiesOrder-of-magnitude economic analyses and Preliminary market surveys to reduce financial uncertainty.
Importance of Conceptual stage
1% of the cost of the product70 % 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 Typical steps:
Subsystem identificationTrade-off studiesSystem integrationInterface definitionPreliminary 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 product85 % 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 establishedContracts made with suppliersProcedures established for product distribution and support. Manufacturing facilities are constructedContinuous process improvement (kaizen)
Product support stage Technical manuals for product installation, operation, and maintenance Training programs for customer personnelTechnical supportsWarranty servicesRepair parts and replacement consumables must be manufactured and distributedNew procedures for operation and maintenanceImproved parts for retrofitNotification 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 DesignSubsystem DesignComponent DesignManufacturing Process Concept DevelopmentManufacturing Process DevelopmentDelivery DevelopmentService DevelopmentDelivery
Concurrent Processes
System Level Design
Subsystem Design
Component Design
Manufacturing Process Concept Development
Manufacturing Process Development
Delivery Development
Service Development
Delivery
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; andEnhance 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 standardsComputer 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 ReleaseConfiguration (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
PRODUCT LIABILITY & SAFETY
Caveat emptor (let the buyer beware)“Privity of contract” (Direct contractual relationship)1916, MacPherson v. Buick (No need for direct contract)Plaintiff must prove negligence1960, Hernington v. Bloomfield Motors, implied warranty1984, Greenman v. Yuba Power Product Strict LiabilityAbsolute 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 systemWill demonstrate specified performance
For a stated period of time
When operated under specified conditions.
Reliability Measures
Reliability R(t)=St /S0
Failure CDF (cumulative distribution function): F(t)=0
t F / S0
Failure PDF (probability density function): f(t) = Ft /S0
Failure or hazard rate: (t)= Ft /St
Simple Reliability Models
Series modelParallel modelSeries- parallel modelBathtub curve
Designing for Reliability
“Start with the best”RedundancyFactor of safety
Maintainability
Maintainability is the probability that a failed systemWill be restored to specified performance
Within a stated period of time
When maintained under specified conditions.
Maintainability
Maintenance downtimeAdministrative & preparation timeLogistic timeActive maintenance time
Types of Maintenance Corrective maintenancePreventive maintenancePredictive 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?