Concept generationLecture 7-8

Andrea Schiffauerova, PhD.

INSE 6411Product Design Theory and Methodology

Textbook - Chapter 7Chapter 7 from The Mechanical Design Process by D. UllmanAdditional materialsThe syringe doser project: http://www.eng.mu.edu/wintersj/b18/projectdef.htm

Concept development process

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Concept generation

• A product concept is an approximate description of the technology, working principles and form of a product.▫ Expressed as a sketch or a rough 3-dimensional model,

usually accompanied by a brief textual description

• A good concept is sometimes poorly implemented, but a poor concept can rarely be manipulated to achieve commercial success.

• Concept generation typically consumes less than 5% budget and 15% of the development time

• Usually, hundreds of concepts are generated, of which 5 to 20 merit serious consideration

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Concept generation dysfunctions

• Common dysfunctions during concept generation:▫ Consideration of only one or two alternatives

▫ Failure to consider carefully the usefulness of concepts employed by other firms

▫ Involvement of only one or two people in the process

▫ Failure to consider entire categories of solutions

▫ Ineffective integration of promising partial solutions

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Concept development - Example

Skeleton Floral Backpack Prickle Backpack Butterfly

Backpack

Tribal Aztec Backpack

Multicolor Buckle Backpack

Pink Floral BackpackBubble Backpack

Panda Backpack

Multi-dot Backpack

Hairy Backpack

Concept generation- Integration of partial solutions

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Multi-dot Backpack - very colorful,

but not interesting design

Bubble Backpack – great design, but not colorful

Multi-dot Bubble Backpack – great design, great colors

Concept generation approach

• Structured approaches reduce the likelihood of costly problems (finding superior concept later, competitor with better concept)

• Concept generation: 5-Step Method:▫ Step 1: Clarify the problem▫ Step 2: Search externally▫ Step 3: Search internally▫ Step 4: Explore systematically▫ Step 5: Reflect on the results and the process

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Concept Generation Process

• Clarify the Problem▫ Problem Decomposition

• External Search▫ Lead Users▫ Experts▫ Patents▫ Literature▫ Benchmarking

• Internal Search▫ Individual Methods▫ Group Methods

• Systematic Exploration▫ Classification Tree▫ Combination Table

• Reflect on the Process▫ Continuous Improvement

Example 1

• A cordless electric roofing nailer

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1. Clarify the problem – Review of assumptionsExample – the nailer

• Review assumptions underlying mission statement, customer needs and target specifications:▫ Mission statement:

Use nails (as opposed to adhesives, screws etc.) Be compatible with nail magazines on existing tools Nail into wood Be hand-held

▫ Customer needs: The nailer inserts nails in rapid succession The nailer works into tight spaces The nailer is lightweight The nailer has no noticeable nailing delay after tripping tool

▫ Target specifications Nail lengths from 25 to 38 mm Maximum nailing energy of 40 J/nail Nailing force of up to 2,000 N Peak nailing rate of 1 nails/second Average nailing rate of 12 nails/min Maximum trigger delay of 0.25 second Tool mass less than 4 kg

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1. Clarify the problem – Problem decomposition

• Many design challenges are too complex to solve as

a single problem.

• Decompose complex problem into simpler sub-problems. ▫ Chronological decomposition (by sequence of actions)

▫ Need-based decomposition (by customer needs)

▫ Functional decomposition (by functions of a product)

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1. Functional decomposition

• Function tells WHAT the product must do, whereas its form, or structure, conveys HOW the product will do it.

• Use action verbs to describe a function

Typical mechanical design functions (using action verbs):

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1. Functional decomposition

• Function is a logical flow of energy, material and information between objects.

• Decompose the problem in terms of the flow of: Materials (position, lift, hold, support, move, translate,

rotate, guide, disassemble, separate, mix, attach…)

Energy (transform, transfer, supply, store, dissipate…)

Information (transport, transform…)

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1. Functional decomposition

• Two steps:1. Find the overall function

Represent the problem as a “black box” Generate a single statement of the overall function on

the basis of the customer requirements

2. Decompose the overall function into sub-functions Describe specifically what the elements of the product

might do to accomplish the overall function The aim:▫ Better understand the problem▫ Control the search for solutions

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1. Functional decomposition:Example 1 - The nailer

1. Find the overall function:- To convert an energy to a controllable force capable of

inserting nails into wood

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Energy MaterialInformation

1. Functional decomposition:Example 1 - The nailer

2. Decompose the overall function into sub-functions

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1. Functional decomposition:Example 2 – The syringe doser

1. Find the overall functionTo convert an energy to a force capable of

drawing controlled doses for a syringe

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A project objective: To design a reliable, low-cost, easy to use mechanism for enabling automated dosing of medications

1. Functional decomposition:Example 2 – The syringe doser

2. Decompose the overall function into sub-functions

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1. Clarify the problem – Problem decomposition• Functional diagram is not unique

• Functional decomposition is best applicable to technical

products

• Two other approaches for Example 1: the nailer

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1. Clarify the problem – Problem decomposition

• The problem decomposition for a product is not unique

• The aim of decomposition techniques is to split a complex problem into simpler sub-problems, then tackle each in a focused way.▫ Select the subproblems most critical to the success of

the product and do them first

▫ Deferring the solution of other sub-problems

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2. Search externally

• The aim is to find existing solutions to either the overall problem or sub-problems ▫ Quicker and cheaper!▫ Focus creative effort on critical sub-problems, or on the ones where no

satisfactory solution exists• An information-gathering process (expand & focus)

• Interview lead users▫ See emerging needs before others▫ Adopt and generate innovations first

• Benchmarking▫ In the markets of related or unrelated products

• Consult experts (with knowledge of one or more subproblems)▫ Technical experts (consultants, suppliers, competitors, researchers)▫ Experienced customers

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2. Search externally• Patents

▫ Search related inventions▫ European patent office: http://ep.espacenet.com▫ US patent office: http://patft.uspto.gov▫ Concepts found in recent patents are protected!

• Published literature▫ Research journals▫ Conference proceedings▫ Trade magazines▫ Handbooks▫ Manufacturers’ catalogs▫ Government reports▫ Consumer information▫ Internet

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http://patft.uspto.gov/

3. Search internally• The use of knowledge and creativity of the team members to

generate product concepts

• Brainstorming▫ Gather ideas contributed spontaneously▫ Suspend judgment (postpone the evaluation until you create

many alternatives)▫ Generate a lot of ideas (explore fully the ‘solution space’)▫ Generate “crazy” ideas (seemingly not feasible, etc.)▫ Combine ideas▫ Draw/sketch/write

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• Brainwriting (Brainwriting 6-3-5)

▫ Similar to brainstorming, but with only written communication

• Both individual or group sessions can be useful

3. Search internally

• TRIZ methodology▫ “Theory of inventive problem solving”▫ A problem solving methodology introduced by Russian

researcher G. Altshuller▫ The key idea is to identify a contradiction (conflict) that is

implicit in a problem. Matrix of characteristics where each cell may represent a conflict The contradiction can be solved by using 40 principles of problem

solving Many current problems have been already solved in different

industries/products/situations There are predictable patterns in the solutions

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• 40 Principles of TRIZ1. Segmentation2. Taking out3. Local Quality 4. Asymmetry 5. Merging 6. Universality 7. “Nested doll”8. Anti-weight9. Preliminary anti-action10. Preliminary action11. Beforehand cushioning12. Equipotentiality13. The other way around14. Spheroidality15. Dynamics16. Partial or excessive actions 17. Another dimension 18. Mechanical vibration19. Periodic action20. Continuity of useful action

21. Skipping22. “Blessing in disguise”23. Feedback24. Intermediary25. Self-service26. Copying 27. Cheap short-living28. Mechanics substitution29. Pneumatics and hydraulics30. Flexible shells and thin films31. Porous materials32. Color changes33. Homogeneity34. Discarding and recovering35. Parameter changes36. Phase transitions37. Thermal expansion 38. Strong oxidants 39. Inert atmosphere 40. Composite material films

3. Search internally

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• 40 Principles of TRIZ – Example of use

3. Search internally

Principle 1. Segmentation

Divide an object into independent parts.• The truck should be bigger but does not fit the space available.

Replace a large truck by a truck and trailer.

Principle 2. Taking out

Separate an interfering part or property from an object, or single out the only necessary part (or property) of an object.

• More powerful compressor is more noisy

Locate a noisy compressor outside the building where compressed air is used

• A dog would be great against the burglary but it is difficult to maintain

Use the sound of a barking dog, without the dog, as a burglar alarm

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3. Search internally

• Evaporating Cloud – a method based on contradictions▫ Develop alternative solutions

▫ Increase understanding of the issue

▫ Steps:1. Determine the conflicting positions

2. Identify the needs

3. Identify the objective (issue)

4. Generate assumptions

5. Generate injections that can

relieve the conflict

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Issue

Need 1

Need 2

Position 1

Position 2

CONFLICT !

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Meet customer’s

requirements

Make it easier for customers

to move and handle

The functions will make the product more attractive over

the competition

Make product smaller

Fit in all the

functions

CONFLICT !

3. Search internally• Evaporating Cloud – an example▫ A company wants to add more functions in order to catch

up with the competition. However, with more functions the product will become larger and heavier.

3. OBJECTIVE 2. NEEDS 1. POSITIONS

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Meet customer’s

requirements

Make it easier for customers to move

and handle

Attractive functions will outperform competition

Make product smaller

Fit in all the

functions

CONFLICT !

Assumptions

Assumptions

Assumptions

Assumptions

Assumptions

Assumptions

Assumptions

3. Search internally• Evaporating Cloud – an example

4. Generate assumptions

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• Evaporating Cloud – an example5. Generate injections that can relieve the conflict

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Meet customer’s

requirements

Make it easier for customers to move

and handle

Attractive functions will outperform competition

Make product smaller

Fit in all the

functions

CONFLICT !

Assumptions

Assumptions

Assumptions

Assumptions

Assumptions

Assumptions

Assumptions

Injection

Injection

Injection

3. Search internally

• Evaporating Cloud – an example▫ Some additional research that might help clarify the

situation: Are all the functions on the products really used?

Can we modularize the product?

Do we really know what the customers want?

▫ Some ideas how to solve the conflict: Plug ins

Modules

Achieving the functions using software

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3. Search internally

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4. Explore systematicallyExample 1 – The nailer

Solutions for two of nailer’s sub-problems

• Many concept fragments!• Concept fragments are solutions to sub-problems

4. Explore systematically

• Systematic exploration is aimed at organizing and synthesizing concept fragments

• Considering all of the possible combinations is impossible!

The goal is to eliminate alternatives and focus on a few good solutions

• Tools for systematic exploration:▫ Concept classification tree

▫ Concept combination table

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4. Concept classification tree

• Concept classification tree divides the entire space of solutions into independent categories to facilitate comparison and pruning

Prune less promising branches (after careful evaluation)

Identify related versus independent approaches

Highlight inappropriateemphasis (certain branches)

Refine problem decomposition

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Example 1 - The nailer

4. Concept classification treeExample 2:The syringe doser

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4. Concept classification treeExample 2 - The syringe doser

4. Concept combination tableExample 1 - The nailer

• Concept combinations table provides a way to consider combinations of solution fragments systematically

• Example - The nailer: 4 x 2 x 3 = 24 combinations to consider

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4. Concept combination tableExample 1 – A solution concept (combination 1)

• Multiple solutions arising from the combination of a motor with transmission, a spring, and single impact. The motor winds a spring, accumulating potential energy which is then delivered to the nail in a single blow

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• Solution from the combination of a motor with transmission, a spring, and multiple impacts. The motor repeatedly winds and releases the spring, storing and delivering energy over several blows

4. Concept combination tableExample 1 – A solution concept (combination 2)

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• Solutions from the combination of a linear motor, a moving mass, and single impact. A linear motor accelerates a massive hammer, accumulating kinetic energy which is delivered to the nail in a single blow

4. Concept combination tableExample 1 – A solution concept (combination 3)

• In this solution concept, a solenoid compresses a spring and then releases it repeatedly in order to drive the nail with multiple impacts

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4. Concept combination tableExample 1 – A solution concept (combination 4)

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4. Concept combination tableExample 2 - The syringe doser

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4. Concept combination tableExample 2 - The syringe doser (solution concepts)

4. Explore systematicallyClassification trees and combination tables• Eliminate infeasible fragments before you combine them• Combine the subproblems that are coupled• Combination tables and classification trees are not

unique▫ Just simple ways to organize thoughts▫ Exploration step acts as a guide for further creative thinking

• Often the concept generation phase is not so straightforward▫ Almost always iterative

• Concept generation is a skill that can be learned and developed

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5. Reflect on the results and the process

• Has the solution space been fully explored?

• Are there alternative function diagrams?

• Are there alternative ways to decompose the problem?

• Have external sources been thoroughly pursued?

• Have ideas from everyone been accepted and integrated into process?

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Next lectures

• March 12▫ Concept generation continued

▫ Assignment #2 presentations Session 4

• March 19▫ Concept selection and testing

▫ Assignment #2 presentations Session 5

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