Redesign for product innovation

Corresponding author:

Shana Smith

[email protected]

product innovation
Redesign for
Shana Smith, Gregory Smith and Ying-Ting Shen, Department of Mechanical

Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road,

Taipei, Taiwan

In today’s market, most companies redesign to create new products. Redesign

improves product quality and reduces cycle time. However, most techniques

limit innovation. They modify a single reference product, which closely matches

user needs, and only introduce new products when major conflicts exist between

user needs and existing products. This study introduces a new redesign for

product innovation approach. The approach combines two or more distinct

reference designs into a single new product. The process creates design conflicts.

The induced conflicts stimulate innovation. At the same time, the approach uses

structured redesign techniques and structured design principles to overcome the

conflicts, which improves solution quality and reduces cycle time. The study also

presents a case study to demonstrate the approach.

� 2011 Elsevier Ltd. All rights reserved.

Keywords: redesign, innovation, user-centered design

After products are on the market for some time, they often need to be

redesigned. There are many reasons for redesigning products. First,

design faults may be found, or customers may change requirements.

Products may also be redesigned to improve quality, reduce costs, extend

product life, or reduce environmental impacts. As a result, redesign is an

important part of the product development process.

In fact, in today’s market, most new products are also developed using rede-

sign techniques. New products are generally derived from similar products

(Li, Kou, Cheng, & Wang, 2006). Therefore, new product design is generally

a derivative work, which consists of changing prior designs to make them suit-

able for new applications. In fact, more than 75% of all engineering design

activity involves reusing prior design knowledge to solve new design problems

(Iyer, Kalyanaraman, Lou, Janyanti, & Ramani, 2003; Lou et al., 2003).

There are many advantages to using a redesign approach to develop new prod-

ucts. Redesign generally improves the quality and efficiency of the product

design process (Li et al., 2006). Redesign solutions are generally more feasible

and reliable, since they have already been used successfully in prior products

(Han&Lee, 2006). Reusing prior design information also reduces product costs,

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Redesign for product inn

required design resources, and cycle time.Therefore, redesign is an important key

to business success (Li et al., 2006).

However, current redesign techniques can also limit product innovation.

Redesign generally focuses on resolving conflicts between current product

needs and prior design capabilities. Most techniques start by choosing a refer-

ence design that reduces conflicts between user needs and product functions, as

much as possible. Remaining conflicts, depending upon their degree, are

resolved by changing component attributes, replacing components, or chang-

ing the structure of the original design (Li et al., 2006). New innovative prod-

ucts are only introduced when major conflicts exist between customer needs

and existing products. However, business success is also strongly related to

product innovation (Howard, Culley, & Dekoninck, 2011). New ideas, new

technologies, and new products capture customer interest and keep successful

companies at the forefront of their industries.

This study introduces a new redesign approach for product innovation. Inno-

vation depends upon generating new ideas (Howard et al., 2011). Generating

new ideas, in turn, depends upon overcoming design conflicts. The approach

stimulates innovation by combining two or more distinct reference designs

into a single new product. The approach, by design, increases both the number

and degree of design conflicts over typical redesign techniques. The induced

conflicts stimulate original ideas and innovative design solutions. At the

same time, the approach uses structured redesign techniques and design prin-

ciples to overcome the induced conflicts, which improves solution quality and

reduces design time.

Following sections describe the redesign approach in more detail. Section 1

gives an overview of prior redesign techniques. Section 2 describes the new

redesign approach. Section 3 presents a case study design problem. Section

4 presents conclusions.

1 Redesign techniquesMany different techniques have been developed for product redesign. The

techniques generally vary, based upon the reasons for redesigning the

products.

1.1 Redesign for conflict resolutionThe most common reason for redesigning a product is to correct design faults.

Design faults or conflicts occur when a finished product does not meet require-

ments. Similar conflicts can occur when customers change existing require-

ments after a product has been introduced. The process generally starts by

creating a product model. The model is generally used to identify design con-

flicts or functional dependencies. Conflicts and dependencies, in turn, identify

the components that must be redesigned to meet requirements.

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162

For example, Li et al. (2006) described a model composed of a system design

description, new system requirements, and conflicts between the design and the

requirements. In the model, designs and conflicts are described by compo-

nenteattribute pairs. The redesign approach consists of diagnosing the exist-

ing system design, identifying conflicts, and resolving the conflicts. Conflicts

are resolved by changing component attributes, replacing components, or

changing the structure of the original design.

As an alternative, Chen, Macwan, and Li (2007) described a design depen-

dency matrix (DDM) model that records dependencies between product func-

tions and the components or parameters used to achieve the design. Matrix

rows correspond to product functions. Matrix columns correspond to compo-

nents or parameters used to achieve product functions. The redesign approach

consists of decomposing the DDM to locate and isolate portions of the model

that must be modified to satisfy requirements.

Case-based methods may be used to find solutions. For example, Liu and

Wang (2001) and Liu (2008) described a case-based model composed of design

change records for a product. The model includes requirements, design

changes, costs, and manufacturing requirements, for all design iterations. In-

formation from previous design iterations can be used to solve new design

tasks. In particular, prior similar design iterations can be copied to reduce re-

design effort.

The solution process may also be automated. For example, Kasarad et al. (2007)

developed a design for adaptation (DFAD)method to create adaptable products.

Adaptable products use look-up tables, fuzzy logic, or linear control algorithms

to self-adjust or self-redesign in response to changing requirements. For example,

an adaptable car might respond to changing requirements by self redesigning

body parts and initiating manufacturing processes to create the new parts.

Techniques for detecting design conflicts, identifying functional dependencies,

and reusing design information to create solutions are all useful elements for

any redesign process. However, the described methods all focus on making

modifications to a specific existing product, rather than on developing a new

product from prior designs.

1.2 Redesign for cost reductionProduct success is generally related to perceived value, the ratio of product

quality to product price. Customers must be willing to purchase a product

at a given price (Bovea & Wang, 2007). Company success is also related to

profit margin, the difference between product price and product cost

(Alizon, Shooter, & Simpson, 2007). Quality can be improved by modifying

a product to improve performance with respect to requirements. However, dif-

ferent techniques are generally needed to reduce costs. In today’s market,

Design Studies Vol 33 No. 2 March 2012


techniques for reducing costs must generally consider the entire product life

cycle, including environmental impacts.

For example, Pnueli and Zussman (1997) described a recycling oriented rede-

sign approach for increasing the end of life value of a product. The approach

uses a weighted AND/OR graph model and heuristic rules to compute the end

of life value of a product, identify weak spots in the design, and automatically

generate design modifications to improve end of life value. The approach

focuses on modifying a single existing product to improve product recovery.

Janz, Sihn and Warnecke (2005) combined value analysis, quality function

deployment (QFD), and life cycle costing into a redesign approach for simul-

taneously improving product life cycle performance and optimizing costs. The

approach aims to increase performance, increase value, and decrease life cycle

costs by replacing existing product components with better lower-cost alterna-

tives that achieve the same functions.

Bovea and Wang (2007) considered environmental requirements with cus-

tomer preferences and product costs in a redesign approach for developing

environmentally conscious products. The approach uses QFD, life cycle

assessment, life cycle cost, and contingent valuation techniques to weigh

increased product costs for environmentally friendly products against

increased customer preference and revenue potential. The approach uses

component-level analysis to determine overall product value, individual com-

ponent values, and components that need to be redesigned to improve environ-

mental impacts or reduce costs.

Yang, Yu, and Sekhari (2011) described a method for redesigning electronic

and electrical (EEE) products into modules to improve maintainability, reus-

ability, and recyclability. The method uses functional assessment to ensure

that the redesigned product meets original functional requirements and

physical risk assessment to ensure that the redesigned product can be assem-

bled. Functional risk assessment is based upon axiomatic design principles.

Physical risk assessment is based upon an assembly graph model. The method

uses a genetic algorithm to find an optimized modular design that meets func-

tional and physical constraints.

Methods for redesigning products to reduce costs are useful. However, they

also focus on making modifications to a specific existing design. They are

not designed to stimulate product innovation.

1.3 Redesign for product family creationCosts can also be reduced by combining products into families. A product

family is a group of related products, which shares common features, compo-

nents, and subsystems, designed to satisfy a variety of market segments

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164

(Simpson, Maier, & Mistree, 2001). A product family is typically designed

around a product platform, which is the set of common elements implemented

across the range of products (McGrath, 1996). Redesigning products into

a product family promotes component reuse between products, which gener-

ally improves product quality, reduces product costs, and simplifies the prod-

uct design process.

Alizon et al. (2007) used a design structure matrix (DSM), value analysis, and

a commonality versus diversity index to redesign an existing family of refrig-

erators. The aim of the study was to redesign each of fifty models to improve

the product family at the module and component levels, without changing the

function of any model. The redesign process consists of breaking down each

product into modules and components, completing value analysis to deter-

mine the value of each module and component in meeting requirements,

choosing new components when needed, creating a DSM to determine inter-

actions between components, creating new component clusters from DSM

results, and choosing common or unique components to maximize a combined

commonality/diversity index for common or unique capabilities between

product models.

Farrell and Simpson (2003, 2010) used a targeted market segmentation grid

and an activity-based costing model to maximize component commonality

and minimize production costs in a highly customized low volume product

line. The redesign approach consists of four steps, developing a set of candi-

date component platforms, testing the feasibility of each candidate platform,

choosing one platform for each product, formulating an optimization problem

with one design variable for each product, and solving the optimization prob-

lem to choose the best platform. They used the approach to redesign yokes on

nuclear grade valves.

Salhieh (2007) described a method for redesigning a heterogeneous product

portfolio into a homogeneous product family. A heterogeneous product port-

folio consists of several related products that initially have no or very few com-

mon components. The method consists of analyzing the existing products to

determine customer needs and product functions, completing a granulation

study to remove redundancies, identifying physical components to deliver

the functions, and grouping components by functionality for parallel develop-

ment. Salhieh used the method to redesign a heterogeneous office product

portfolio, which consisted of a desk, book shelf, drawers, and computer table,

into a homogeneous product family.

Methods for redesigning products into families consider multiple reference

products. However, the methods aim to increase component commonality,

reduce design effort, and increase profit margin, without changing the overall

functionality of any of the products. As a result, the methods may limit, rather



than stimulate, new product innovation. In contrast, the redesign approach in-

troduced in this study combines functions from two or more distinct products

into one new product. The new method stimulates, rather than limits, product

innovation.

1.4 Redesign for product developmentOther redesign techniques have been developed for creating new products

from prior designs. However, the techniques generally choose one reference

design that minimizes conflicts between current product needs and prior design

capabilities. As a result, the techniques may also limit, rather than stimulate,

innovation.

For example, HanandLee (2006) describeda case-basedmethod for creatingnew

design solutions from previous design concepts. The method was developed for

creatingmotion transmissionmechanisms frommechanisms contained in catalogs

or handbooks. The method extracts underlying design concepts from existing

designs, creates conceptual building blocks from the derived information, and

combines the conceptual building blocks into new design alternatives, using adap-

tation rules. Design concepts are represented by acyclic graphs with links that rep-

resent mechanisms and nodes that represent motions. They used the method to

design a sewing machine, a windshield wiper, and a fuel line needle valve.

2 Redesign for product innovationThis study introduces a new redesign approach for product innovation. The

approach combines two or more distinct reference designs into a single new

product. Using two or more distinct reference designs increases both the num-

ber and degree of design conflicts over typical redesign techniques. The

induced conflicts stimulate original ideas and innovative design solutions.

The approach uses structured redesign techniques and structured design prin-

ciples to overcome the induced conflicts, which improves solution quality and

reduces design time over traditional product design techniques.

The new redesign approach consists of ten steps: choose target product, iden-

tify needs, choose reference products, identify components, build a component

factor table, determine component factor weights, extract key components,

identify conflicts, apply design principles, and verify results.

2.1 Choose target productNew product development depends upon a clear understanding of market

trends and customer needs. As a result, successful design techniques depend

upon effective communication between customers and designers. In this study,

the redesign for innovation approach chooses a target product based upon

customer surveys. For example, customer surveys might indicate that cus-

tomers want a cell phone that has better high-resolution camera capabilities.

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Table 1 User needs

1

Cell phon

User needs

1 Easy to view2 Easy to use3 Durable4 Fade resistant

166

2.2 Identify needsIn general, traditional redesign techniques ask users to describe their needs for

the finished target product, directly. The redesign for innovation approach cre-

ates a finished product from two or more distinct reference designs. Therefore,

the approach asks users to describe their needs for each of the reference

designs, separately. For example, customer surveys can be used to capture

user needs for a cell phone and for a high-resolution camera, separately.

The approach captures user needs with weights, fi,j, for each reference product

i and each user need j, as shown in Table 1. As an example, in this study, cus-

tomer surveys contain a fixed list of user needs or functions for each reference

product, customers choose a limited number of functions from each list, and

Equation (1) is used to calculate weights

fi;j ¼ n

N� 100% ð1Þ

for each reference product i and each user need j. In Equation (1), n ¼ number

of subjects that chose user need j, and N ¼ total number of subjects.

The approach increases the number and degree of design conflicts over tradi-

tional redesign techniques. Increasing conflicts stimulates original ideas and

innovative design solutions.

2.3 Choose reference productsAfter determining the target product and the target functions that customers

would like to have, traditional redesign techniques choose a single reference

product for redesign, for example, a camera-phone that best matches user

needs. In contrast, the redesign for innovation approach chooses two or

more distinct reference products that can be combined into a single new prod-

uct that meets user needs, for example an existing cell phone product and an

existing high-resolution portable camera product.

Products

2

e High-resolution camera

Weights User needs Weights

f1,1 1 Easy to view f2,1f1,2 2 Easy to use f2,2f1,3 3 Automatic f2,3f1,4 4 Versatile f2,4


Table 2 Product clusters

Clusters

1 Electronics

2 Office products

3 Machine tools


The reference products must belong to the same product cluster. A product

cluster is a group of heterogeneous products that use different physical compo-

nents to perform similar functions. Table 2 shows three example product clus-

ters: a cell phone, digital camera, PDA, and GPS; a fax machine, copy

machine, and scanner; a CNC lathe, drill, and mill.

2.4 Identify componentsIn this step, the approach separates each reference product into basic compo-

nents. The process consists of describing each design as a set of solution func-

tions, progressively expanding solution functions into sub-functions, and

matching the fully expanded sub-functions to basic product components. Ide-

ally, each of the resulting function-structures contributes to the overall product

function, independently. As an example, Figure 1 shows function-structures for

a cell phone reference product and a high-resolution portable camera reference

product.

2.5 Build a component factor tableAfter separating the reference products into function-structures, the approach

builds a component factor table. In a redesign for innovation component fac-

tor table, components with similar functions, from different reference prod-

ucts, are considered different levels of the same component (or factor). For

Products

1 2 3 4

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Figure 1 Reference product

function-structures

168

example, in Figure 1, reference product 1 (a cell phone) has a screen. Reference

product 2 (a high-resolution portable camera) also has a screen. The two

screens may operate differently, and they may have different dimensions. How-

ever, the redesign for innovation approach considers the two screens different


Table 3 Compone

Components

1 Screen2 Shell3 Lens4 Buttons5 Battery


levels of the same screen factor. Table 3 shows an example component factor

table for the cell phone and high-resolution portable camera reference

products.

2.6 Determine component factor weightsIn this step, the approach identifies the impact of each component on each user

need, as shown in Table 4. The process is similar to the QFD approach (Akao,

2004). However, with the QFD approach, designers assign fixed-value impact

weights (1, 3, or 9) for each component on each user need. With the redesign

for innovation approach, designers also assign impact weights. However, in

this study, they assign impact weights in linguistic terms: very high (VH),

high (H), medium (M), low (L), and very low (VL). The redesign for innova-

tion approach is more detailed. However, the linguistic terms must be trans-

formed into numerical values.

In this study, Chen and Hwang’s (1992) approach is used to convert linguistic

terms to fuzzy numbers. Chen and Huang’s approach transforms linguistic

terms into triangular fuzzy numbers defined over the interval [0, 1]. Table 5

shows the fuzzy weights used to convert linguistic terms into fuzzy numbers

and crisp values, wi,j,k for each product i, user need j, and component k.

Table 6 shows component factor weights for the high-resolution camera refer-

ence product. For example, w2,1,1 ¼ 0.909.

2.7 Extract key componentsAny given redesign task typically does not require changing all components. In

this step, the approach identifies the important components for a given rede-

sign task. In this study, Equation (2) is used to compute the importance of

each component Ci,k in product i.

I�Ci;k

� ¼XNi

j¼1

fi;j,wi;j;k ð2Þ

nt factor table

Products

1 2

Cell phone Camera

1 21 21 21 21 2

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Table 5 Linguistic terms with

Linguistic term

Crisp value

Table 4 Linguistic component factor weights

Product

2

High-resolution portable camera

User needs Components

1 2 3 4 5

Screen Shell Lens Buttons Battery

1 Easy to view VH L H VL VL2 Easy to use VH M H VH L3 Automatic H VL VH M L4 Versatile VH M VH H L

170

In Equation (2), Ni is the number of user needs in product i, fi,j is the impor-

tance weight of each user need j, and wi,j,k is the impact weight of each compo-

nent Ci,k on each user need j. For the example camera reference product, from

Tables 1 and 6,

IðC2;1Þ ¼ 0:909� f1;1 þ 0:909� f1;2 þ 0:717� f1;3 þ 0:909� f1;4 ð3Þ

The result depends upon both user and designer input.

The same component might have different importance values in different ref-

erence products. In this study, the final importance value for component k is

the maximum importance value of the component for any of the reference

products

IðCkÞ ¼max½IðCi;kÞ� ð4Þ

The approach chooses the most important components, those with highest

importance values, as key components for redesign. In this study, 50% of

the components, those with highest importance values are chosen as key

components.

2.8 Identify conflictsIn this step, the redesign for innovation approach uses Taguchi analysis to

identify interactions between key components. The approach is more detailed

corresponding fuzzy weights

VH H M L VL

0.909 0.717 0.500 0.283 0.136


Table 6 Component factor weights

Product

2

High-resolution portable camera


1 2 3 4 5

Screen Shell Lens Buttons Battery

1 Easy to view 0.909 0.283 0.717 0.136 0.1362 Easy to use 0.909 0.500 0.717 0.909 0.2833 Automatic 0.717 0.136 0.909 0.500 0.2834 Versatile 0.909 0.500 0.909 0.717 0.283


than the corresponding QFD approach for determining interactions between

component factors. With the QFD approach, designers assign interaction

levels (þþ, þ, ‘none’, �, ��) to each pair of components. With the redesign

for innovation approach, customers or designers rate the overall performance

of different Taguchi design combinations. Statistical analysis identifies compo-

nent interactions from the design ratings.

To complete the Taguchi analysis, the redesign for innovation approach iden-

tifies potential component interactions, calculates degrees of freedom, and cre-

ates an orthogonal design array. Customers or designers rate the performance

of each design. Statistical analysis identifies component interactions from the

design ratings.

For example, the component factor table in Table 3 contains five components,

with two levels per component. Components and levels in Table 3 represent 32

possible designs. In general, testing all possible designs might not be possible.

As a result, the approach may use Taguchi analysis to create a minimum

orthogonal set of designs for testing. Customers or designers rate each design.

Statistical analysis identifies actual interactions between component factors.

Negative interactions indicate design conflicts that must be overcome by the

redesign process. A complete example of the process is given in the case study.

2.9 Apply design principlesThere are different techniques for generating creative solutions to design prob-

lems. However, Howard et al. (2011) showed that structured techniques, such

as case studies or structured design principles, are generally more effective than

unstructured techniques. For many design problems, case study information

may not exist. Therefore, in this study, the redesign for innovation approach

finds design solutions by applying structured design rules or principles. Differ-

ent rule sets can be used, for example, axiomatic design rules, inventive design

principles, or adaptation rules.

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172

2.10 Verify resultsFinally, the redesign for innovation approach evaluates the new product

design in a design review. Product design is an iterative process. Therefore,

the process repeats until the final design satisfies customers, designers, and

all design requirements.

3 Case studyThis section describes a case study that was used to demonstrate the redesign

for product innovation approach. The case study follows the ten-step redesign

process.

3.1 Choose target productIn the case study, the redesign process used surveys to determine that cus-

tomers wanted a bicycle that can be easily converted into an exercise bike.

3.2 Identify needsThe process also used a customer survey to determine user needs. In all, 103

subjects completed the survey, 61 male subjects and 42 female subjects. All

subjects were students or workers from an urban university environment,

with ages between 18 and 35. The survey contained 2 reference designs

(i ¼ 1, 2). Product 1 was a bicycle, with 19 user needs (i ¼ 1, j ¼ 1e19), and

product 2 was an exercise bike, with 16 user needs (i ¼ 2, j ¼ 1e16). Each sub-

ject was allowed to choose at most 8 needs for each reference design. Equation

(1) was used to calculate the weight of each user need.

Table 7 presents survey results. For example, 57 subjects chose ‘brand’ as an

important need when purchasing a bicycle. Thus, the weight of the ‘brand’

need for the bicycle reference design is

f1;1 ¼ 57

103� 100%¼ 55:3% ð5Þ

3.3 Choose reference productsFigure 2 shows the bicycle and the exercise bike reference products used to

complete the case study product design project. Both reference products

were chosen as reasonably close matches to users’ expressed needs for the sep-

arate reference designs.

3.4 Identify componentsFigure 2 also separates each reference product into basic components. In

Figure 2, the bicycle consists of 7 basic components: ‘fork’, ‘frame’, ‘pedal’,

‘derailleur’, ‘saddle’, ‘screen’, and ‘wheel’. The exercise bike consists of 6 basic

components: ‘fork’, ‘frame’, ‘pedal’, ‘derailleur’, ‘saddle’, and ‘screen’. The

exercise bike does not have a functional ‘wheel’ component. The bicycle and

the exercise bike have six common components.


Table 7 User needs

Products

1 2

Bicycle Exercise bike

User needs n f1,j User needs n f2,j

1 Brand 57 55.3 1 Brand 45 43.72 Style 76 73.8 2 Style 33 32.03 Price 96 93.2 3 Price 88 85.44 Comfort 81 78.6 4 Comfort 73 70.95 Customize 4 3.9 5 Customize 13 12.66 Light 49 47.6 6 Light 19 18.47 Purpose 53 51.5 7 Safety 61 59.28 Safety 49 47.6 8 Small 41 39.89 Small 14 13.6 9 Security 4 3.910 Security 30 29.1 10 Anti-rust 18 17.511 Anti-rust 23 22.3 11 Basket 9 8.712 Basket 25 24.3 12 Easy to store 46 44.713 Two-person 8 7.8 13 Easy to maintain 29 28.214 Easy to store 24 23.3 14 Special pedal 23 22.315 Portable 20 19.4 15 Screen 68 66.016 Crashworthy 21 20.4 16 Derailleur 54 52.417 Easy to maintain 39 37.918 Screen 4 3.919 Derailleur 28 27.2


3.5 Build a component factor tableTable 8 shows the resulting component factor table for the two case study ref-

erence products. The table includes 7 functional components (k ¼ 1e7). All of

the components have two levels, one for each reference product, except for the

‘wheel’ component. The bicycle can have a ‘large’ or a ‘small’ ‘wheel’ compo-

nent. The exercise bike does not have an equivalent functional ‘wheel’

component.

3.6 Determine component factor weightsIn this step, designers provide a linguistic impact weight for each component

on each user need. Tables 9 and 10 show the linguistic component factor

weights designers assigned to components in the bicycle reference product

and the exercise bike reference product. To complete subsequent steps, fuzzy

weights from Table 5 must be used to convert the linguistic terms in Tables

9 and 10 into fuzzy numbers and crisp values.

3.7 Extract key componentsIn this step, Equation (2) was used to compute the importance of each compo-

nent Ci,k, for each product i. For example, the importance of the front fork for

the exercise bike is

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Figure 2 Reference products

174

IðC2;1Þ ¼X16

j¼1

f2;j,w2;j;1

¼ 43:7� 0:136þ 32:0� 0:717þ 85:4� 0:717þ 70:9

�0:500þ 12:6� 0:717þ 18:4� 0:500þ 59:2� 0:717þ 39:8� 0:717

þ3:9� 0:136þ 17:5� 0:717þ 8:7� 0:500þ 44:7� 0:717þ 28:2

�0:717þ 22:3� 0:717þ 66:0� 0:136þ 52:4� 0:136

¼ 303:6 ð6Þ

Equation (4) was then used to find the final importance value of each compo-

nent for each reference product. For example, the final importance value of the

front fork is


Table 8 Component factor table (k [ 1e7)

Components Products

1 2

Bicycle Exercise Bike

1 Fork 1 22 Frame 1 23 Pedal 1 24 Derailleur 1 25 Saddle 1 26 Screen 1 27 Wheel 1 (large) 2 (small) 3 (no wheel)

Table 9 Component factor we

User needs

1

For

1 Brand VL2 Style H3 Price M4 Comfort H5 Customize H6 Light H7 Purpose H8 Safety M9 Small H10 Security L11 Anti-rust H12 Basket M13 Two-person M14 Easy to store H15 Portable H16 Crashworthy H17 Maintain L18 Screen L19 Derailleur L


IðC1Þ ¼ max�I�C1;1

�; I

�C1;2

��

¼ max½375:8; 303:6�¼ 375:8 ð7Þ

Table 11 shows final importance values for all components. The four compo-

nents with the highest final importance values (‘fork’, ‘frame’, ‘derailleur’, and

‘wheel’) were chosen for redesign analysis.

ights for bicycle (i [ 1, j [ 1e19, k [ 1e7)

Components

2 3 4 5 6 7

k Frame Pedal Derailleur Saddle Screen Wheel

VL VL VL VL VL VLH M L M VL MH L M M H MH M H VH L MM H H H M HVH VL L L L HH L H H H MM L L L L MVH L M L L VHH VL VL L VL LVH M H L L HVH VL VL H VL VLH VL H L VL HVH L M L M VHVH L M L M HH L L L H MM H H L H LL L L L VH LM L VH L L M

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Table 10 Component factor weights for exercise bike (i [ 2, j [ 1e16, k [ 1e6)


1 2 3 4 5 6

Fork Frame Pedal Derailleur Saddle Screen

1 Brand VL VL VL VL VL VL2 Style H H L L M L3 Price H H M H M H4 Comfort M M L L H VL5 Customize H L M M H M6 Light M H L L L M7 Safety H H L M L L8 Small H H L M L M9 Security VL VL VL VL VL VL10 Anti-rust H H M H L L11 Basket M H L VL M VL12 Easy to store H H L M L L13 Easy to maintain H L M H M M14 Special pedal VL VL VH VL VL VL15 Screen VL VL VL VL VL VH16 Derailleur VL VL VL VH VL VL

Table 11 Final importance va

Products

1

Fork

1 Bicycle 375.82 Exercise bike 303.6I(Ck)max 375.8

176

3.8 Identify conflictsIn this step, the redesign for innovation approach uses Taguchi analysis to

identify interactions between key components. To complete the Taguchi anal-

ysis, the approach identifies potential component interactions, calculates

degrees of freedom, and creates an orthogonal design array. Customers or

designers rate the performance of each design. Statistical analysis identifies

component interactions from design ratings.

For the case study, designers rated every possible design combination. Sta-

tistical analysis identified an interaction between the ‘wheel’ and ‘frame’

components, as shown in Figure 3. According to designers, adding a small

wheel to an exercise bike frame improves product performance. Adding

lues for components

Components

2 3 4 5 6 7

Frame Pedal Derailleur Saddle Screen Wheel

457.8 224.6 313.8 304.5 265.3 333.0291.8 192.2 273.8 213.5 241.6 0.0457.8 224.6 313.8 304.5 265.3 333.0


Figure 3 Interaction between

‘frame’ and ‘wheel’

components


a large wheel to an exercise bike frame negatively impacts performance.

Adding a large wheel to a bicycle frame improves performance. To create

a combined product, the redesign approach must resolve the conflict

between wheel size and frame type. The conflict creates an opportunity

for product innovation.

3.9 Apply design principlesThis step uses structured design principles to resolve the design conflict

between wheel size and frame type. From the Taguchi analysis, the ‘wheel’

‘volume’ parameter may cause the conflict between wheel size and frame

type. According to designers, small wheels improve exercise bike performance;

large wheels improve bicycle performance. A bicycle and an exercise bike can

differ in size. As a result, ‘frame’ ‘volume’ could also cause the conflict in the

combined bicycleeexercise bike product. Redesigning a bicycle frame to

include exercise bike functions could cause ‘frame’ ‘volume’ to increase, which

could negatively impact bicycle performance. In addition, if customers want to

convert a bicycle into an exercise bike, ‘frame’ ‘ease of operation’ could also

cause the conflict.

As a result, two component parameter contradictions could cause the inter-

action between wheel size and frame type: (1) ‘wheel’ ‘volume’ and ‘frame’

‘volume’, or (2) ‘wheel’ ‘volume’ and ‘frame’ ‘ease of operation’. Increasing

exercise bike ‘wheel’ ‘volume’ to increase bicycle performance increases

‘frame’ ‘volume’, which decreases exercise bike performance. Alternatively,

increasing bicycle ‘frame’ ‘volume’ to include exercise bike functions may

increase ‘wheel’ ‘volume’, which decreases exercise bike performance. Alter-

natively, increasing ‘wheel’ ‘volume’ to increase bicycle performance

decreases ‘frame’ ‘ease of operation’, when converting the bicycle into an

exercise bike.

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To demonstrate the redesign for innovation approach, the case study uses

structured inventive principles to resolve conflict 2, the conflict between

‘wheel’ ‘volume’ and ‘frame’ ‘ease of operation’, in a combined bicycle-

exercise bike product. Four inventive principles can be used to resolve the

conflict: (1) segmentation, (2) dynamics, (3) partial or excessive actions, or

(4) transformation of properties. To demonstrate the redesign for innova-

tion approach, the case study uses both segmentation and dynamics to

resolve the given design conflict. The two techniques produce two different

designs.

3.9.1 SegmentationSegmentation can be accomplished by: (1) separating an object into smaller

parts, or (2) separating an object into modules. For the exercise bike

reference product, the resistance derailleur is integrated with the frame.

However, the resistance derailleur does not contribute to frame perfor-

mance. As a result, for the combined bicycleeexercise bike product, the

resistance derailleur can be separated from the frame. To convert the bicycle

into an exercise bike, users can attach the external resistance derailleur to the

bicycle. As a result, bicycle ‘wheel’ ‘volume’ can be increased without nega-

tively impacting ‘frame’ ‘ease of use’. Figure 4 (a) shows the resulting design

concept. In Figure 4 (b), component A is a support, which attaches the

derailleur component to the rear wheel hub of the bicycle. Component

B is a rotating shaft, which supports the rear wheel of the bicycle. Compo-

nent C is a resistance derailleur, which provides resistance to the rear wheel

of the bicycle, through rotating shaft B.

3.9.2 DynamicsDynamics can be accomplished by: (1) allowing the characteristics of an

object, external environment, or process to change to be optimal or to find

an optimal operating condition, (2) dividing an object into parts capable of

movement relative to each other, or (3) making an object movable or adaptive,

if it is rigid or inflexible. For the combined bicycleeexercise bike product,

a moveable resistance derailleur can be used to achieve bicycle or exercise

bike functions. To convert the bicycle into an exercise bike, users can engage

a clutch mechanism.

Figure 5 shows the resulting design concept. Component A is a resistance

derailleur component for an exercise bike. Gear B is the drive gear

attached to the bicycle pedal. Gear C is connected to the resistance

derailleur. When gear B is disengaged from gear C, as shown in

Figure 5 (a), the device functions like a bicycle. When gear B is engaged

with gear C, as shown in Figure 5 (b), resistance is transmitted through

the gear set. In Figure 5 (b), users can lower the stands and use the device

like an exercise bike.


Figure 4 Redesign using

segmentation


3.10 Verify resultsIn a final design review, designers rated the Figure 5 design more innovative

and easier to use than the Figure 4 design. There are several existing prod-

ucts, similar to the Figure 4 design, for converting a regular bicycle into

an exercise bike. Designers also rated exercise bike performance higher for

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Figure 5 Redesign using

dynamics

180 Design Studies Vol 33 No. 2 March 2012


the Figure 5 design. However, designers rated bicycle performance higher for

the Figure 4 design. As a result, designers rated the Figure 5 design

most likely to meet user needs for a bicycle that can be easily converted

into an exercise bike. The results can be further verified through user

evaluations.

4 ConclusionsRedesign is an important part of the product development process. Redesign is

used to correct design faults, improve product quality, reduce costs, extend

product life, and reduce environmental impacts. In today’s market, redesign

is also used to create most new products. Redesign improves new product fea-

sibility and reliability, and reduces product development costs, design

resources, and cycle time.

However, current redesign techniques can also limit product innovation. Most

techniques choose a reference product that matches user needs, as much as

possible, and modify the reference product to resolve remaining conflicts.

New innovative products are only introduced when major conflicts exist

between customer needs and existing products. However, business success is

strongly related to product innovation. New ideas, new technologies, and

new products capture customer interest and keep successful companies at

the forefront of their industries.

This study introduces a new redesign approach for product innovation. Inno-

vation depends upon generating new ideas. Generating new ideas, in turn,

depends upon overcoming design conflicts. The approach stimulates innova-

tion by combining two or more distinct reference designs into a single new

product, which increases both the number and degree of design conflicts

over typical redesign techniques. The induced conflicts stimulate original ideas

and innovative design solutions. At the same time, the approach overcomes

the induced conflicts by applying structured redesign techniques and design

principles, which improves solution quality and reduces design time over tra-

ditional product design techniques.

The redesign for innovation approach may be implemented in different ways.

In this study, the approach chooses a target product, determines reference

designs, and identifies and ranks user needs, based upon customer surveys.

The approach chooses two or more reference designs that can be combined

to create the target product. Users describe and rank their needs for each of

the reference designs, separately. The approach chooses actual reference prod-

ucts, based upon survey results, separates each reference product into basic

components, and builds a component factor table. The component factor table

considers components with similar functions, from different reference prod-

ucts, as different levels of the same component.

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182

Designers assign weights for the impact of each component on each user need.

In this study, designers use linguistic terms to describe the relationships

between user needs and component functions. The approach uses fuzzy logic

techniques to convert linguistic weights to fuzzy numbers and crisp values. The

approach combines user and designer weights to identify key components that

must be redesigned to create the new product.

The approach uses Taguchi analysis to identify interactions between key com-

ponents. In contrast, most new product design techniques use Taguchi analysis

to evaluate new design options. With the redesign for innovation approach,

customers or designers rate the overall performance of different Taguchi

designs combinations. Statistical analysis identifies component interactions

from the design ratings.

The redesign for innovation approach finds design solutions by applying struc-

tured design principles to resolve the design conflicts. Finally, the redesign for

innovation approach uses design reviews to evaluate the new product design.

Product design is an iterative process. Therefore, the process repeats until the

final design satisfies customers, designers, and all design requirements.

This study also presents a case study to demonstrate the redesign for product

innovation approach. The case study used the approach to create an innova-

tive multi-functional bicycleeexercise bike product from two reference prod-

ucts, a bicycle and an exercise bike. In the case study, Taguchi analysis

identified a conflict between ‘wheel’ and ‘frame’ components for the two refer-

ence products. Adding a small wheel to an exercise bike frame improves prod-

uct performance. Adding a large wheel to an exercise bike frame negatively

impacts performance. Adding a large wheel to a bicycle frame improves

performance.

The conflict created an opportunity for product innovation. To create the

combined product, the redesign approach used ‘wheel’ ‘volume’ and ‘frame’

‘ease of operation’ parameters and both segmentation and dynamics principles

to resolve the conflict between wheel size and frame performance. The two

techniques produced two different designs.

In a final design review, designers rated the dynamics design more innovative

and easier to use than the segmentation design. Designers also rated exercise

bike performance higher for the dynamics design. However, designers rated

bicycle performance higher for the segmentation design. As a result, designers

rated the dynamics design most likely to meet user needs, overall, for a bicycle

that can be easily converted into an exercise bike. The results can be further

verified through user evaluations.



Case study results show that the redesign for innovation approach can be used

to stimulate new product innovation, using a redesign approach that also

improves new product feasibility and reliability. Innovation can improve busi-

ness success, capture customer interest, and keep companies at the forefront of

their industries. At the same time, the redesign approach can also reduce prod-

uct development costs, design resources, and cycle time.

ReferencesAkao, Y. (2004). QFD: Quality function deployment - integrating customer require-

ments into product design. Productivity Press Inc.Alizon, F., Shooter, S. B., & Simpson, T. W. (2007). Improving an existing prod-

uct family based on commonality/diversity, modularity, and cost. Design Stud-ies, 28(4), 387e409.

Bovea, M. D., & Wang, B. (2007). Redesign methodology for developing environ-mentally conscious products. International Journal of Production Research

4057e4072.Chen, S., & Hwang, C. (1992). Fuzzy multiple attribute decision making: Methods

and applications. Lecture notes in economics and mathematical systems.

Springer-Verlag.Chen, L., Macwan, A., & Li, S. (2007). Model-based rapid redesign using decom-

position patterns. Journal of Mechanical Design, 129(3), 283e294.

Farrell, R. S., & Simpson, T. W. (2003). Product platform design to improve com-monality in custom products. Journal of Intelligent Manufacturing, 14, 541e556.

Farrell, R. S., & Simpson, T. W. (2010). Improving cost effectiveness in an exist-ing product line using component product platforms. International Journal of

Production Research, 48(11), 3299e3317.Han, Y. H., & Lee, K. (2006). A case-based framework for reuse of previous

design concepts in conceptual synthesis of mechanisms. Computers in Industry,

57(4), 305e318.Howard, T. J., Culley, S. J., & Dekoninck, E. A. (2011). Reuse of ideas and con-

cepts for creative stimuli in engineering design. Journal of Engineering Design,

22(8), 565e581.Iyer, N., Kalyanaraman, Y., Lou, K., Janyanti, S., & Ramani, K. (2003). A recon-

figurable 3D engineering shape search system part I: shape representation.

ASME 2003 International Design Engineering Technical Conferences and Com-puters and Information in Engineering Conference, Chicago, IL.

Janz, D., Sihn, W., &Warnecke, H. J. (2005). Product redesign using value-orientedlife cycle costing. CIRP Annals - Manufacturing Technology, 54(1), 9e12.

Kasarad, M. E., Terpenny, J. P., Inman, D., Precoda, K. R., Jelesko, J.,Sahin, A., & Park, J. (2007). Design for adaptability (DFAD)dA new conceptfor achieving sustainable design. Robotics and Computer-Integrated

Manufacturing, 23(6), 727e734.Li, Z. S., Kou, F. H., Cheng, X. C., & Wang, T. (2006). Model-based product

redesign. International Journal of Computer Science and Network Security,

6(1), 99e102.Liu, X. (2008). Research on product design knowledge reuse through linkage with

design iteration records. IFIP International Conference on Network and Parallel

Computing 510e515.Liu, X., & Wang, Y. (2001). Flexible case retrieval on the web for product design

support. Mechanical Science and Technology, 7, 716e719.

ovation 183

184

Lou, K., Jayanti, S., Iyer, N., Kalyanaraman, Y., Prabhakar, S., & Ramani, K.(2003). A reconfigurable 3D engineering shape search system part II: databaseindexing, retrieval, and clustering, ASME 2003 International Design Engineer-ing Technical Conferences and Computers and Information in Engineering Con-

ference, Chicago, IL.McGrath, M. (1996). Setting the pace in product development. A guide to product

and cycle-time excellence. Revised Edition. USA: Butterworth-Heinmann.

Pnueli, Y., & Zussman, E. (1997). Evaluating the end-of-life value of a productand improving it by redesign. International Journal of Production Research,35(4), 921e942.

Salhieh, S.M. (2007). Amethodology to redesign heterogeneous product portfoliosas homogeneous product families. Computer-Aided Design, 39(12), 1065e1074.

Simpson, T. W., Maier, J. R., & Mistree, F. (2001). Product platform design:

method and application. Research in Engineering Design, 13, 2e22.Yang, Q., Yu, S., & Sekhari, A. (2011). A modular eco-design method for life

cycle engineering based on redesign risk control. International Journal ofAdvanced Manufacturing Technology. doi 10.1007/s00170-011-3246-1.


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