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

no

no

no

no

yes

yesno

yes

no

no

yes

nono

no

no

no

yes

yes

yes

no

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

no

yes yes no

Swatch Sampling

D

E

D

D

F G

H

C

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