Post on 21-Dec-2015
transcript
Creativity and Constraints in Design
Claudia Eckert
Introduction Companies must innovate
Create distinct products Create needs through improved products Meet new requirements Meet legislative and regulatory environment
Companies must not innovate Innovation introduces novelty, novelty introduces risk Design takes time
Complex products are designed by modification
Introduction Engineering design is complex, e.g. car, aircraft, engines
100s of people design 1000s of parts Legacy designs Very few people have an overview of the product
Companies use systematic approaches Stage-gate processes 6 Sigma Business Process Excellence
When and where can engineering designers be creative?
Overview• Creativity• Our studies
– Diesel engines– Knitwear design
• Constraints on design problems– What are constraints– Constraints in different domains
• Objective evaluation of how constraints are met• Constraints and drivers as a theory of design
Creativity• The act of creating something new, a new insight, a new
theory, or a novel design• Measuring creativity?
– Novelty– Unobviousness
• Ways of being creativity– Analogy– Concept blending– Reframing the problem
Creativity in Engineering Design
product planning
concept development
system design
product planning
testing & refinements
production ramp-up
mission approval
conceptapproval
system specapproval
detail specapproval
production approval
New ideas Creative problem solving
requirements solutionprinciple
system architecture
detaileddesign
validation
Complex products are designed by modification
Methodology• Interviews and observation of industrial practice• Knitwear
– 1991–1998: communication and inspiration– Ca. 80 interviews in 26 companies
• Engineering– Since 1999: over 150 interviews
• Engineering change• Process planning• Communication• System architecture• Testing
• Construction– Since 2006: refurbishment, energy consumption
Example of Source of Inspiration in Knitwear
Resulting Design
Design cycle for sources of inspiration
Solution
Reformulation of Problem
Requirement / Perceived Need/ Brief
End
Selection of Source
Adaptation of Source
Analysis of Source
Evaluation
Discard
Discard
Internal Evaluation
Pattern Fits ?
Meets Design Brief?
Meets Design Brief?
Technical Sketch
Discard
Discard
Accept
END END
Select Design Framework
Detailed Design
Swatch Sampling
Specific Design Research in Companies
Briefing of Designers by Buyer
Yarn Selection
Develop Design Framework
Swatch Sampling
Buyer Presentation
START START
Use Parts
Alter
END
END
END
yes
yes
no
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yesno
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nono
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Research
Design
Sampling
B
General Fashion Research in Companies A Fashion Research in Retail Chains B
yes
Like?
Create Fabric Sample Create Cutting Pattern
FeasibleEconomicalConsistent Pattern Placing
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yes yes no
Swatch Sampling
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Overall knitwear design process
• Research
• Design
• Sampling
Sources of inspiration in design process
Different Perspectives on Adaptation of Sources of Inspiration
• Context: constraints of design space for timely consumer products• Starting point: design which is modified to meet new requirements• Precedents: canonical (first) solutions to a class of problems• Reuse: reemployment of components in new designs• Patterns: abstract solution embodiments for class of problems• Translations of sources: adaptation from different product class• The primary generator: constraints from external object on design• Reference points: sources of inspiration as a language of design
The case study• System architecture definition
– Distinct phase in most process models
• The product: Off highway diesel engine
• Great product variety• Stable core design
– Solution principles unchanged for generations– “we start where we left off with the previous generation”– Radical innovation for emission legislation – Innovation in periphery
• Development time is reduced – Early engagement with all potential customers– Very structured approaches: requirement cascade– Replacement of intuition by mathematical models in decision making
The organisation• In UK, but part of US multinational
– Manufacturer of engine-as-a-component– Standardization across all sub-companies
• Suppliers• Methods• R&D
• Business Process Excellence– R&D separate from design– Only “tried and tested” technology in new project– Aim: take innovation out of development projects
Reuse, Novelty and Changes• Significant number of components are carried over• Novelty is minimised
– New components– New uses for existing components
• Reasons for reluctance to change– Reliability history: known parts have known behaviour– Development effort: change of any kind costs money– Optional components: redevelopment for all options– Capital cost of change: manufacturing and test facilities and the
dealer network– Economies of scale for engine components: reduced unit cost
– Manufacturing and service complexity: fewer parts mean fewer mistakes
Requirements Cascade
Key customer requirements
FMEAReuse
Key performance parameters
Conflicts Cust. Req.
Performance Parameters
Conflicts Cust. Req.
Mathematical modellingand simulation
Mathematical modellingand simulation
Emission
Business Req.
Detailed design• Briefs written by component teams• Design based on assumptions through “shared vision”
• Role of system architect: Shifts from specification to arbitration– Between different component teams– Between component teams (form) and CAE (performance)– Dealing with change propagation
• “Sausage machine”• Few designs created from scratch, Pugh analysis to evaluate
them
Creativity in integration• Problems emerge in integration that are hard to
anticipate• Tight constraints on space, budget, time • “Emergency innovation”• Leads to creative solutions
– Become planned-in features for next generation
Engineering creativity• Engineering design is creative, but word creativity never
mentioned• System architecture design was elusive
– Dispersed throughout first four stages of process– Implicit in constraints in requirement cascade– Clear when it was needed, but not how it was created
• Mathematical models very dominant– Result of BPE approach– Replace much tacit knowledge
• BPE “squeezes out” creativity– Technology development in R&D– Problem solving in detailed design
Constraints• A constraint is a restriction that an action or the solution of
a problem must comply with• Design constraints vary
– explicitly stated or tacitly assumed– conformity is binary or a matter of degree– measurable physical properties or are experiential– measured objectively or matter of subjective judgement – hard or soft
• Sources of constraints– The problem or the need that the design must meet– The process by which this is achieved– The emerging solution
Uneven constraints• Many design processes and
problems are in parts over-constrained and in parts under-constrained
• Provide trade-off spaces• Under-constrained areas
provide scope for creativity
Constraints in engineering• Highly constrained from the beginning of the process• Requirement cascade brings in constraints incrementally
and therefore creates a well constraint structure• Problems at the end of process are highly constrained• Creativity lies in
– Reframing the problem, so that constraints can be reordered or dropped
– Finding clever solutions to problems with as little change from the existing design as possible
Constraints in knitwear• Fashion constrains new design
– Constraints are tacit– Designers need to find constraints
• Individual designs are under-constrained– Roughly fit the body– Needs to meet financial targets
• Design process is a constraint seeking process by fixing decisions– Themes– Colours– Inspirations– Etc.
Knitting and diesel engines
Process
Product
Emerging Solution
Project Organisation User / Markets
User requirements
Legislation
Cost
Time
Novelty target
Product family Trajectory
Human resources
Official processes
Project plan
Lead times
Freezes
Decisions order
Emerging competitor products Parallel
developments Margins
Platform
Manufacturing resources
Key technology
Meeting constraints• Engineering
– Constraints are explicit– Constraints are measurable – Conformity can be measured– Tests are guarantor of quality– Individual success separable from product success
• Knitting– Constraints are largely tacit– No objective evaluation of design quality– Designers or brand as guarantor of quality– Product success is personal success
Outlook: drivers and constraints as a theory of design• Drivers are issues generating clusters of constraints to
apply to range of products– Product complexity– Safety criticality – Product lifespan– Volumes – Product connectivity– Etc.
• Drivers and constraints allow the prediction of the behaviour of individual processes
Conclusions• Constraints and drivers explain a lot about individual
processes• Defining a “definitive” set of constraints and drivers
would be huge endeavour• Deciding whether this constitutes a theory is very much
a matter of deciding what design is.
The case study• Methodology
– Long standing collaboration with the company– Interview with company expects: ca 1 hour– Transcribed and analysed
# Team Specific role Number of interviews
1 Product 3
2 Product Concept team 2
3 Product Design architect 1
4 Product 2
5 Product Design architect 2
6 Component Leader 1
7 Component Leader 1
8 Component 1
9 CAE Systems engineering team
1
10 Programme 1
Product development teams• Product team for specific engine:
– Products Director, who initiates the NPI process;– Multidisciplinary Concept Team; – Design Architect oversees the design and co-ordinates activities.
• Component teams: experts for specific components– Work on multiple engines
• CAE (Computer-Aided Engineering) teams
– modelling and simulation to predict the behaviour of the engine (performance, mechanical stress, thermal flows, vibration levels etc.) from the component designs.
• Manufacturing: manufacture and assembly• Programme team:
– planning and tracking the schedule of the NPI process.
The NPI process
Market need identified, concept team/budget assembled
Groundwork completed, relevant research in place
Key geometry fixed, technologies narrowed to 2-3 candidates
Focus shifts from engine level to component level, manufacturing comes in
Engine released to production, manufacturing process put in place.
Engine productionised.
Start of production
Review 1 year after start of production.
Technologies selected, production intent design finished, capital committed for production.
Engine-level requirements cascaded down to individual component properties
Design architect
Component teams
CAE teams
Manufact.
Launch GW 7GW 1 GW 2 GW 3 GW 4 GW 5 GW 6Product directors
Concept team