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(LeanPD) Towards Lean Product and Process
Development
Article in International Journal of Computer Integrated Manufacturing · October 2011
DOI: 10.1080/0951192X.2011.608723
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Towards lean product and process development
Muhammad S. Khan
Mikel Sorli
d
a
, Ahmed Al-Ashaab
& Amaia Sopelana
a
, Essam Shehab
a
, Badr Haque
b
c
, Paul Ewers ,
d
a
Decision Engineering Cent re, Manuf act uring Depart ment , Cranf ield Universit y, Cranf ield,
MK43 0AL, UK
b
Engineering Syst ems & Services, Rolls Royce Plc, Derby, UK
c
Elect ronics Product Group, Vist eon Engineering Services Lt d. , Chelmsf ord, UK
d
Innovat ion Syst ems Unit , Tecnalia, Bizkaia, Spain
Available online: 03 Oct 2011
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International Journal of Computer Integrated Manufacturing
2011, 1–12, iFirst article
Towards lean product and process development
Muhammad S. Khana, Ahmed Al-Ashaaba*, Essam Shehaba, Badr Haqueb, Paul Ewersc,
Mikel Sorlid and Amaia Sopelanad
a
Decision Engineering Centre, Manufacturing Department, Cranfield University, Cranfield, MK43 0AL, UK; bEngineering Systems
& Services, Rolls Royce Plc, Derby, UK; cElectronics Product Group, Visteon Engineering Services Ltd., Chelmsford, UK;
d
Innovation Systems Unit, Tecnalia, Bizkaia, Spain
Downloaded by [Cranfield University] at 04:43 08 November 2011
(Received 31 January 2011; final version received 24 July 2011)
Successes in lean manufacture have led researchers and practitioners to consider extending ‘lean’ to different parts of
the engineering enterprise, including product and process development (PPD). Lean product development (PD) has
been understood to mean lean manufacture applied to PD, while the roots of lean PD – just like lean manufacture –
go back to Toyota. This article presents the methodology adopted in order to pave the way towards a coherent lean
PD model that combines lessons from the Toyota product development system (TPDS) with other best practises.
The article provides a unique review of the lean PD research area, and a reference framework for the enablers that
Toyota has employed for lean PD. An investigation of five engineering enterprises undertaken to search for evidence
of the implementation of lean PD enablers through observation, document analysis and interviews is also presented.
Some enablers have been informally applied, while few have been formally implemented, and no model was found to
formally combine lean PD enablers into a coherent whole. This is the first article to critique attempts to describe lean
PD and provide a definition for Lean PD.
Keywords: lean product development; Toyota development; product development; product design; set based
concurrent engineering; continuous improvement; process modelling; design for manufacture; process innovation;
knowledge based engineering
1. Introduction
The challenges faced by engineering companies are
fierce and many find themselves struggling for mere
survival. The entire engineering enterprise is being
compelled to improve; some of the pressures include
economic crises, evolving market demands, stiff global
competition and the need to improve time-to market
(Yelkur and Herbig 1996, Murman et al. 2000, Molina
et al. 2005, de Brentani 2010). Lean thinking – an
improvement philosophy which focuses on the creation
of value and the elimination of waste – is a potential
weapon in this struggle.
Lean thinking has been a subject of research for
nearly two decades, the focus of which has been on
improving manufacturing processes (Khalil and Stockton 2010), as well as administration, management and
the supply chain. However, new engineering products
continue to under-perform in their lead times, cost and
quality. There has been comparatively less research
done to apply ‘lean’ to product and process development (PPD): the design process, from the concept stage
to the detailed development of products and their
related manufacturing processes. This is rather strange,
as PPD has the greatest influence on the profitability of
*Corresponding author. Email: a.al-ashaab@cranfield.ac.uk
ISSN 0951-192X print/ISSN 1362-3052 online
Ó 2011 Taylor & Francis
http://dx.doi.org/10.1080/0951192X.2011.608723
http://www.tandfonline.com
any product (Duverlie and Castelain 1999). One
possible reason for this is the ‘room for creativity’
and subsequent unstructured approach in traditional
product design. Research undertaken to improve PPD
with lean thinking may prove instrumental in the
progress of engineering.
The term lean product development (PD) has been
understood to mean lean manufacturing applied to
PD, while the roots of lean PD – just like lean
manufacturing – go back to Toyota. However,
researchers and practitioners have taken various routes
in their attempts to describe or propose an approach to
lean PD. Through this research, the authors seek to
define lean PD and its supporting constituents.
This article presents a review and analysis of the
lean PD research area, and investigates the various
approaches taken by researchers and practitioners.
Based on the review, a framework for the enablers of
lean PD has been proposed, which provides a
foundation for the building blocks of lean PD. The
article also describes the outcome of an industrial field
study of five engineering enterprises, which is undertaken to search for evidence of the implementation of
lean PD enablers.
Downloaded by [Cranfield University] at 04:43 08 November 2011
2
M.S. Khan et al.
The research presented in this article has been
conducted as part of a collaborative European
research project titled ‘Lean Product and Process
Development (LeanPPD)’. The project – initiated in
January 2009 and expected to conclude by January
2013 – is supported by the European Commission for
research (FP7/NMP-2008-214090).
The structure of the article follows the sequence of
research, which begins with a description of the
research approach in Section 2, followed by a brief
background to lean manufacturing and subsequently
lean PD in Section 3. Different approaches to lean PD
are analysed in Section 4 and an overall analysis of the
research area and the research that is required to
progress towards a holistic implementation of lean PD
is provided in Section 5. The article then presents a
reference framework for lean PD enablers in Section 6,
followed by the results and analysis of an industrial
field study undertaken to search for evidence of the
implementation of lean PD enablers in Section 7.
Section 8 provides a number of conclusions drawn
from the research presented and recommendations for
future work.
2.
Research approach
The authors have endeavoured to analyse the work
done in the lean PD research area, understand the
different approaches and identify some research trends
in the field. Approaches have been classified in order to
provide an overview of the research area, research gaps
have been identified and future research in this area is
proposed. The employed research approach is depicted
in Figure 1.
In order to identify relevant literature, a number of
methods were employed. Keyword searches were used
across a number of databases including Scopus,
ProQuest, Springerlink, Emerald and Science Direct.
Keywords that were used include: lean PD, lean model,
lean design, lean engineering, PD value, amongst
others. The searches resulted in hundreds of journal
and conference papers which were reviewed and
filtered. Library searches and internet websites (e.g.
Amazon) were also used to identify other literature
such as text books.
Another technique that was employed was backtracking through the references of the relevant papers.
The resulting literature has been analysed in Section 4.
In order to develop a clearer understanding of lean
PD, a framework was developed in order to structure
the building blocks of lean PD (enablers). This
framework was based on content analysis of the
reviewed literature and includes the techniques and
tools that form the foundation of lean PD. The
framework is presented as a table in Section 6.
Figure 1.
Research approach diagram.
Five engineering companies from the automotive,
aerospace and home appliances sectors were visited
and observed by researchers in order to develop an
understanding of the context. The needs and interests
of each company were understood through various
exercises involving both face-to-face and virtual teleconference meetings. The purpose of these activities
was to understand how lean PD could help the
companies to improve their PD. This interaction with
industry is part of the clinical methodology that has
been employed, wherein researchers adopted a collaborative approach with companies and plan to have an
active role in the implementation of theory and analyse
the impact of their research.
Based on the understanding gained from the
literature review and industrial visits, a structured
questionnaire was developed in order to search for
evidence of the implementation of lean PD enablers.
This was a difficult task as the questions had to address
multiple lean PD enablers simultaneously and took
over 3 months to develop. The questionnaire was used
to guide the explorative study through face-to-face
interviews with managers and engineers. Thirty seven
employees were interviewed from the five companies
both in small groups and individually to get a rich set
of results. The results from these interviews were later
analysed and conclusions were drawn.
3.
The foundation of lean PD
Lean has become one of the most popular words in
engineering improvement initiatives. In the foundation
book The machine that changed the world (Womack
et al. 1990), the term ‘lean’ was described as a
combination of principles and ideas developed by
Toyota and described earlier by Taichi Ohno (Ohno
1988) to describe the Toyota production system (TPS).
Further work in 1996 titled ‘Lean Thinking’ detailed
important aspects such as value, waste, and the five
core lean principles (Womack and Jones 2003).
The term lean was initially used in reference to
manufacturing operations; lean is now being used
Downloaded by [Cranfield University] at 04:43 08 November 2011
International Journal of Computer Integrated Manufacturing
across a spectrum of sectors. The term lean has become
confusing as some label Toyota practise as lean
(Womack et al. 1990), while others label good practise
as lean (Mynott 2000). Lean thinking is no doubt
based on Toyota methods, and much of the lean
literature describes Toyota practises. Baines et al.
(2006) identified a difference between earlier works,
where the focus was on waste elimination and latter
works that which focused on value creation. One
reason for this may be because earlier works focused
on manufacturing operations, whereas latter works
attempted to apply the same principles to different
settings. Browning (2003) draws a similarity between
engineering and an athlete, and argues that simply
losing weight will not allow you to win a race. He
quotes a number of cases where companies have overemphasised on efficiency which resulted in lost
production and sales, although such a causative
relationship is not easy to prove. Lean manufacturing
has evolved as its own discipline, and many have tried
to adopt lean manufacturing principles to other parts
of the engineering enterprise. However, one of the
questions addressed in this article is: should the source
of lean PD be the evolved lean manufacturing
discipline or Toyota PD?
The term ‘lean production’ was first published by
John Krafcik in a Sloan Management Review article
in 1988, (Krafcik 1988) based on his master’s thesis
at the MIT. Krafcik (1988) had been a quality
engineer in the Toyota-GM New United Motor
Manufacturing (NUMMI) joint venture in California
before his MBA studies at MIT. Krafcik’s (1988)
research was part of the International Motor Vehicle
Program (IMVP) at MIT, which resulted in the
aforementioned book The machine that changed the
world (Womack et al. 1990). Prior to the term ‘lean’,
the TPS was referred to as ‘fragile’ perhaps due to
the scepticism of the US researchers who initiated
the case study. The IVMP program actually had two
initial phases, both led by Professor Daniel Roos,
the founding director of MIT’s engineering systems
division. The first 5-year research program began in
1979 aimed at understanding the future role of the
automobile, while the second 5-year program began
in 1985 aimed at measuring and describing the gap
between the Western World and Japan (Holweg
2007).
While the focus of research at MIT was on the TPS,
Allen Ward, a professor of mechanical engineering at
the University of Michigan (UM) was more concerned
with PD. Allen had initially completed his PhD at
MIT – at the same time as the IVMP – in artificial
intelligence for automating engineering design, wherein
he realised that conventional PD was fundamentally
flawed and stumbled upon what he coined set-based
3
concurrent engineering (SBCE): a unique PD process
(Sobek et al. 1999, Ward 2007).
Allen Ward later joined UM and continued in this
research area and he began a case study with a number
of PhD students and later with Jeffrey Liker, a
professor of industrial and operations engineering.
Allen was considered as the leading US authority on
Toyota’s PD process and was the technical expert for a
2-year collaborative project with the National Centre
for Manufacturing Sciences in Michigan. The project
(initiated by GM/Delphi) titled ‘Product Development
Process – Methodology and Performance Measures’
aimed to understand how to make substantial PD
improvements by studying world class companies that
had distinguished themselves with a combination of
high quality products and fast time to market
(Kennedy 2003).
4. Approaches to lean PD
Researchers and practitioners took different journeys
once they realised the potential benefit that PD could
gain by becoming ‘Lean’. These approaches may be
separated into five categories, as presented in Table 1:
(1) Those who rebranded concurrent engineering
as Lean PD.
(2) Those who viewed ‘Lean’ as lean manufacturing – as described in the various texts analysing
TPS – and tried to adapt the various constituents to make sense to PD; in some cases, lean
manufacturing was mixed with other theories
and approaches in order to ensure the proposed
Lean PD approach was relevant to PD.
(3) Those who appreciated the foundation of Lean
PD to be the Toyota product development
system (TPDS), but – probably due to the lack
of literature on the topic – incorporated some
elements of TPDS into the five lean principles
combined with other ideas from lean manufacturing and tried to apply this combination to
PD.
(4) A fourth group that identified the foundation
of ‘lean’ to be Toyota and went to great extents
to study TPDS from the Toyota Motor
Company and identified a more comprehensive
set of principles and mechanisms directly
related to PD that were argued to be theoretically superior to any of the PD theory that
was previous identified.
(5) A fifth group has recently emerged where
practitioners have attempted to apply Toyota
PD concepts in their companies; this group is
reliant on group 4 for their principles and
mechanisms.
4
Table 1.
M.S. Khan et al.
Approaches to lean product development.
Approach
Downloaded by [Cranfield University] at 04:43 08 November 2011
Rebranding concurrent
engineering as Lean
PD
Adapting ideas from
Lean Manufacture to
PD in combination
with other theories
Integrating elements of
TPDS with Lean
Manufacturing
principles and
methods and applying
them to PD
Describing Toyota
concepts based on a
case study of TPDS
Author
Year
Title
Karlsson and Ahlstrom
1996
The difficult path to lean
product development
Mynott
2000
Fiore
2003
Cooper and Edgett
2005
Anand and Kodali
2008
Reinertsen
2009
Haque and JamesMoore
2004
Oppenheim
2004
Huthwaite
2004
Lean product
development
Lean strategies for
product development
Lean, rapid and
profitable new
product development
A conceptual framework
for LNPD
The principles of
product development
flow
Application of lean
principles to product
introduction
Lean product
development flow
Lean design solution
McManus et al.
2005
Lean engineering: doing
the right things right
Hines et al.
2006
Towards lean product
lifecycle management
Mascitelli
2006
Schuh et al.
2008
The lean product
development
guidebook
Lean innovation:
introducing value
systems to product
development
Ward et al.
1995
Sobek et al.
1998
Sobek et al.
1999
Kennedy
2003
Morgan and Liker
2006
Ward
2007
Kennedy et al.
2008
The second Toyota
paradox: how
delaying decisions can
make better cars
faster
Another look at how
Toyota integrates
product development
Toyota’’s principles of
set-based concurrent
engineering
Product development for
the lean enterprise
The Toyota product
development system:
integrating people,
process, and
technology
Lean product and
process development
Ready, set, dominate:
implement Toyota’’s
set-based learning for
developing products
and nobody can catch
you
Source/Publisher
Journal of Product
Innovation
Management
American Technical
Publishers
Quality Press
Product Development
Institute
International Journal of
Product Development
Celeritas Publishing
Journal of Engineering
Design
Systems Engineering
Institute for Lean
Innovation
1st International
Conference on
Innovation and
Integration in
Aerospace Sciences
Journal of
Manufacturing
Technology
Management
Technology Perspectives
Proceedings to Portland
International
Conference 2008 on
Management of
Engineering &
Technology
Sloan Management
Review
Harvard Business
Review
Sloan Management
Review
The Oaklea Press
Productivity Press
Lean Enterprise Institute
Oaklea Press
(continued)
5
International Journal of Computer Integrated Manufacturing
Table 1. (Continued).
Approach
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Practitioners attempting
to apply Toyota
concepts in PD
Author
Year
Title
Oosterwal
2010
Schipper and Swets
2009
The lean machine: how
Harley-Davidson
drove top-line growth
and profitability with
revolutionary lean
product development
Innovative lean
development: how to
create, implement and
maintain a learning
culture using fast
learning cycles
All of these groups used Toyota’s success to
support their approaches; however, Toyota’s success
was not achieved by the approaches described by
groups 1–3. Rather Toyota’s success was due to the
approach that they themselves adopted and their PD
practices may have contributed significantly. This
means that only the researchers that focused purely
on TPDS can justify such a claim (groups 4–5).
Benchmarking is not a new practise. Its origin is
often quoted as the measurement of feet on a bench by
cobblers, while later it was re-contextualised to
company performance measurement (Cooper and
Kleinschmidt 1995). The Japanese – while initiating
their automobile industry – used benchmarking when
they visited the US automobile giants, as well as other
European companies (Ohno 1988). The US used
benchmarking in the IMVP and the University of
Michigan (UM) Toyota PD case study to evaluate and
learn from Toyota and other Japanese companies. The
global community develops as a whole and learns from
each other to achieve excellence. This does not mean
that one company will not outperform its competitors,
nor does it mean that a company will disclose its
advanced capabilities. Benchmarking, however, must
be done properly, and once complete should not be
generalised as an all-encompassing solution. Those
who adapted lean manufacturing to PD may have
witnessed some short-term benefits. However, lean
manufacturing was extracted from the TPS and not the
TPDS.
When you try to apply manufacturing principles
and mechanisms to PD, there are a number of
inconsistencies: the output value is not a physical
product received by a customer, eliminating waste does
not identify poor quality, and value stream mapping
(VSM) is based on the assumption that you have
already got all the required value-adding steps in your
process, etc. Another assumption is that five principles
are sufficient for PD as they were for manufacturing;
however, Morgan and Liker – who based their work
Source/Publisher
AMACOM
Productivity Press
on a case study of Toyota PD – developed 13 principles
which were specific to PD (Morgan and Liker 2006).
Based on the analysis that has been described, the
authors believe that Lean PD should refer to PD
theory that is based on the critical elements of Toyota
PD and not lean manufacturing. Once lean PD is
established – based on Toyota PD – then it may evolve
into a discipline in its own right. This was the case with
lean manufacturing and similarly lean PD must not be
constrained to Toyota practices, and must be a
dynamic system that is always improving and responding to the challenges that PD faces. Currently research
conducted in this area is limited and it must be steered
in the right direction, to avoid mistakes in theory and
practice.
5.
Progressing towards lean PPD
The Toyota-centric Lean PD research that has been
conducted describes Toyota PD principles and mechanisms, and their advantages over typical PD
approaches. The research provides minimal evidence
of the effectiveness of applying Toyota PD methods
outside of Toyota. One reason for this is that the area
of research is fairly new, and has been overshadowed
by lean manufacturing and lean enterprise research.
Another possible explanation may be a cultural barrier
that inhibits the ideas of ‘left-shifting work’ and
developing multiple alternative designs instead of a
single design, which is the foundation of SBCE.
Based on the review of this research, the authors
believe that there are five core enablers of Toyota and
indeed lean PD:
(1) SBCE process;
(2) Chief engineer (entrepreneurial) technical
leadership;
(3) Value-focused planning and development – this
includes customer value, profit, amongst other
attributes;
6
M.S. Khan et al.
(4) Knowledge-based (KB) environment;
(5) Continuous improvement (Kaizen) culture.
The authors propose the following definition for
lean PD:
Downloaded by [Cranfield University] at 04:43 08 November 2011
‘Lean PD is value-focused PD. Value is a broad term
used to define stake-holder needs and desires. SBCE is
a strategic and convergent PD process guided by
consistent technical leadership throughout. SBCE
enables the focus on value and in particular knowledge
and learning. Continuous improvement is the culture
and an outcome of the SBCE learning process’.
The authors believe that Toyota has developed
their PD system to support these five core enablers and
all other techniques and tools support them. Some may
contest that the combination and management of
people and tools are the foundation of Toyota PD;
however, many other companies have advanced
management and organisational methods as well as
state of the art tools that may be equivalent or superior
to their Toyota equivalents (Meyer 2008). The author
believes that the chief engineer leadership system is,
however, an important enabler.
Through this review the authors identified that
there is no comprehensive model that describes an
integrated lean PD process and framework. Subsequently, there have been no structured attempts to
perform a lean PD case study with an informative
before and after measurement. A number of researchers have identified this gap and mentioned it as an area
of future work in their concluding statements. Ward
et al. (1995) suggested that Toyota’s approach is not
well defined or documented, and that methodologies
need to be tested in different companies before
formulating a complete theory. It may be said that
significant effort has been made to define and document Toyota’s approach; however, different researchers have done so unilaterally. Further work is required
to define the parameters of the lean PD research area
and also to test the methodologies in different
companies. Thus a complete and tested theory that
integrates Lean PD into a holistic system which is
transferable to other companies is yet to be established
(McManus et al. 2005). Sobek et al. (1999) went to
great lengths to study and document Toyota’s SBCE
approach; however, research is still required to
construct a methodology for SBCE, integrated into a
full PD process model that combines Toyota PD
principles and mechanisms. This integrated model
would require thorough investigation to substantiate
its effectiveness and would need to be applied to a
number of case studies across multiple engineering
sectors in order to claim its general effectiveness for
PD. Process-related factors have been downplayed by
some academics who consider organisational strategies
to be the key to success (Cusumano 1994, Cusumano
and Nobeoka 1998). Although we do not dispute the
importance of organisational strategy, it is vital to
translate organisational strategy into processes in
order to achieve enterprise success.
6.
The building blocks of lean PD
A framework of lean PD enablers was developed to
represent lean PD. Methods, tools and techniques that
have been described by the researchers and practitioners who base their work on Toyota PD were
documented and analysed. Twenty-one lean PD
enablers are agreed upon by consensus of these
researchers (Ward et al. 1995, Morgan and Liker
2006, Kennedy et al. 2008), while 26 enablers were
mentioned in a number of publications but not by
consensus. This may be due to the research manuscript
being incomplete such as in the case of Ward (2007),
restricted to part of the puzzle (Ward et al. 1995, Sobek
et al. 1999), or constrained to a particular case study
(Kennedy 2003, Kennedy et al. 2008). The framework
provides a categorisation of the 46 enablers; categories
include core enablers, techniques and tools. The core
enablers for lean PD are depicted in Figure 2 and their
combination is referred to as the conceptual LeanPPD
model.
SBCE is a unique PD process, and is considered as
the main enabler for lean PD by some researchers
(Ward 2007). Other enablers that have been described
are either embodied within or support this process.
Design participants practice SBCE by reasoning,
developing and communicating about sets of solutions
in parallel. As the design progresses, they gradually
narrow their respective sets of solutions based on the
knowledge gained. As they narrow, they commit to
staying within the sets so that others can rely on their
communication (Sobek et al. 1999). The SBCE process
is illustrated in Figure 3. SBCE comprises of a number
of characteristics including exploring multiple alternatives, delaying specification, a minimal constraint
policy (‘delayed commitment’), extensive prototyping
Figure 2.
The conceptual lean PPD model.
International Journal of Computer Integrated Manufacturing
Downloaded by [Cranfield University] at 04:43 08 November 2011
Figure 3.
Set-based concurrent engineering process.
(or simulation), and convergence upon the optimum
design. PD integration/target events are another
important enabler. These events are unique design
reviews used to guide the set-based process. Supplier
strategy also resonates through the research, with the
focus being on inter-locking key suppliers (keiretsu).
Empowering suppliers to develop their own set-based
approach can enable reduced supplier tracking and
provide more room for innovation.
A number of additional design techniques are
employed early in the design process, such as mistake
proofing (Poke Yoke) and early problem solving,
considering potential action scenarios to ensure conceptual robustness, and designing in quality. A design
structures plan is also developed by each functional
department to work out the main features of the
design.
Another design technique that can support lean PD
is ‘test-to-failure’ (Ijiwara in Japanese), wherein prototypes are tested to breaking point. The aim of this
technique is to learn more about designs and their
thresholds, and produce ‘limit curves’ which capture
the results. This technique forms part of the ‘test-thendesign’ approach, wherein decisions are made after
designs have been tested and factual knowledge
(evidence) is provided. Matrices for comparing design
concepts and quality (e.g. quality function deployment) are also employed to aid in decision making.
The concept of value-focus is mentioned by all
researchers, and the differentiation between product/
customer value and process/enterprise value is also
echoed (an example of process value is knowledge).
VSM has also been mentioned briskly by all researchers, which may be indicative of its limited application
in PD or lack of clarity as to how it should be applied.
A strategic approach to PD is employed by Toyota
which allows projects to be used to increase process
value (knowledge, capabilities, etc.) A product portfolio is categorised into project types (facelift projects,
7
minor modifications, major modifications, new product family, etc.). Each category has a standard
duration and follows a regular drumbeat with standard
intervals. These development projects extract mature
technologies from advanced technology teams that
focus on research. Once a design is sufficiently mature
for launch, its release may be staggered to align with a
multi-project plan that ensures the strategic launch of
new products. This process is symbolic of the holistic
systems thinking that Toyota applies to PD.
The Chief Engineer technical leadership is another
enabler in which a technical leader is involved prior to
conception and remains at the helm throughout the
entire PD process. The chief engineer follows a shared
company vision and is responsible for the production
of a design concept document, which is used to
communicate the vision for the product system.
Cross-functional module development teams also
play a role in the chief engineer system.
Another major enabler is a knowledge-based
environment in which learning more about the design
alternatives is the focus of PD activities. Ensuring
knowledge is pulled by upstream processes as opposed
to pushed by downstream processes is another
important factor which ensures that knowledge flows
and is received in the right place at the right time.
Mechanisms for capturing, representing and communicating knowledge support the KB environment.
These include: trade-off curves, check sheets, technical
design standards and rules, and A3 single-sheet
knowledge representations, which are primarily used
for problem solving. These methods collectively
provide a means for rapid communication and
comprehension. Digital engineering including CAD,
CAM, CAE and other simulation software also
support the KB environment. A learning organisation
culture wherein employees are rewarded and appreciated for their technical contribution is another
echoed enabler. Junior employees are mentored by
senior employees who train their students how to
approach technical problems in addition to passing on
a wealth of tacit knowledge. Learning cycles such as
plan-do-check-act (PDCA) and look-ask-model-discuss-act (LAMDA) represent the general problemsolving approach. This collaboration sustains an
expert workforce which is empowered to make
decisions and do their own responsibility-based planning. Another enabler is a KB engineering system, also
known as a ‘know-how’ database. The KB engineering
system captures knowledge in a centralised database,
with the capability to locate and extract required
information easily. Another frequently employed
technique is a lessons learnt process wherein experiences are reflected upon (Hansei in Japanese) and
captured in the KB engineering system. Lessons learnt
8
M.S. Khan et al.
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may also be published in books and provided to
employees.
A culture for continuous improvement (Kaizen) in
addition to formal methods to incorporate improvements have been suggested to be part of lean PD.
Standardisation of processes, skills and design
methods allows continuous improvement to be
regularly considered upon review. The Toyota
approach to problem solving (Obeya in Japanese)
is a pertinent example, where an A3-single sheet
problem report is prepared and then used as the
focal point of collaborative meetings in team rooms.
The aim is to share the problem, take counsel and
arrive at a consensus for decisions. This often
Table 2.
includes some root-cause analysis and an investigation known as ‘5 whys’ where the source of a
problem is identified.
A number of other enablers have been mentioned
by a single researcher or group, and may be relevant
enablers for lean PD. However, due to the unilateral
mention and based on the critical analysis conducted,
it is likely that they are not fundamental lean PD
enablers.
The enablers for lean PD have been structured into
a framework, presented in Table 2. The five core
enablers are composed of techniques (methods or subenablers) and tools (hardware, software, documents,
etc.).
Framework for lean PD enablers.
Core enablers
Set-based concurrent engineering
Value-focus (planning and
development)
Chief engineer technical leadership
Knowledge-focus (knowledge-based
environment)
Continuous improvement (Kaizen)
culture
Techniques
Multiple alternatives (designed)
Delaying specification
Minimal constraint
Extensive simulation/prototyping
(possibly including full-scale
models)
Early problem solving
Test-then-design
Supplier strategy (supplier types and
interlocking)
Supplier set-based concurrent
engineering
Mistake proofing
Design in quality
Robust design methods
Integration/target events
Value-stream mapping
Customer-focus (customer needs/
wants)
Multi-project plan and strategy
Cross-functional module
development teams &and
manufacturing involvement
Knowledge/information flow/
cadence/pull (in right place at right
time)
Knowledge reuse
Expert workforce development
Mentoring by senior employees
Test-to-failure
Rapid learning/comprehension
A3 group problem solving
Learning cycles (PDCA/LAMDA)
Root-cause analysis and 5 whys
Employee empowerment/individual
responsibility
Lessons learnt reflection process
Standardisation of processes, skills,
and design methods
Separating research from
development
Tools
Design concepts matrix
Quality matrix (QFD)
Design structures functional plan
Design concept document
Digital engineering (CAD/CAM/
CAE/simulation, etc.)
Trade-off curves
Check sheets/lists
KB engineering system (know-how
database)
Limit curves
A3 single-sheet problem reports
Technical design standards and rules
Standard architectures (and
modularity)
International Journal of Computer Integrated Manufacturing
In order to develop a complete LeanPPD model, all
or most of the above mentioned enablers should be
present, and in particular the core enablers. Some of
the techniques and tools may, however, be replaced by
an equal or superior equivalent.
7.
Lean PD in industry
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Five engineering companies have been analysed as part
of this research in order to search for evidence of the
implementation of the lean PD enablers described in
Section 6. These include the following:
. one aerospace company that design and make
engines for a number of sectors;
. one automotive original equipment manufacturer company;
. two automotive first tier supplier companies;
. one home appliances original equipment manufacturer company.
All of the companies face a variety of challenges in
PD, including barriers to innovation, late design
changes, communication issues and knowledge-related
problems. The companies are interested in improving
their processes, and the application of new methods
and tools. Each of the companies do, however, face
resource restrictions mainly due to economical factors.
Initial interaction with industry involved various
discussions through virtual web-based meetings, and
face-to-face meetings at a number of European
locations. Researchers also visited each of the five
engineering companies at their locations and observed
both PD and production activities. This included over
100 h of interaction. PD documentation, depicting
processes and models were provided for analysis.
Meetings were held in order to understand industrial
needs and to ensure an industrial-driven approach to
the research.
Based on the understanding gained from the
literature review and industrial visits, a structured
questionnaire was developed. The questionnaire was
used to guide the explorative study through face-toface interviews with managers and engineers. It was
important for these interviews to be face-to-face so
that the behaviours and expressions of the candidates
could be analysed and evidence could be requested by
the interviewer for the answers provided. Thirty-seven
candidates have been interviewed from the five
companies, including project managers, lead engineers,
engineering managers and design engineers. Each
interview ranged from 90 to 120 min depending on
the responses from the interviewees. Multiple interviews were conducted in the same company in order to
gain a better overall picture, without losing the
9
individual views and opinions. The survey was
conducted between March and July of the year 2010.
Results from the interviews were analysed qualitatively. The following considerations were made during
the analysis of results in order to ensure that the results
represent PD and not just the individual, without
neglecting individual opinions and perceptions:
. Role in organisation: Responses from managers
were weighted higher for questions that were
related to organisational processes, while responses from engineers were weighted higher for
design methods and tools employed in PD.
. Years of experience: Responses from interviewees who have been working for the organisation for a longer duration were generally
weighted higher, as they often had a better
understanding of PD at their organisation.
. Consensus: Where there was a consensus of
responses, it was quite certain that the answer
was representative of the organisation, whereas if
the answers varied then further analysis was
required to provide a single representative result
or a combined result representing different
opinions or views.
. Incorrect responses: Some interviewees guessed,
or answered without the required knowledge,
such answers generally became apparent to the
interviewer and were logged during the interview,
and in some cases became apparent when
comparing results.
. Transcripts: Notes taken during the interviews
were consulted while analysing results, to ensure
that the context of each answer was understood
and in some cases the behaviour of the
interviewees.
The questionnaire was used to investigate whether
or not the 46 enablers depicted in Table 2 have been
formally implemented through direct and indirect
questions. Examples of the question that were asked
include:
(1) Do you have flexibility in how you do your job?
(2) Is there a technical leader who is responsible for
the entire development of a product from
concept to launch?
(3) Every specification is a compromise between
what customers want and what can be provided. How is a product specification stabilised
in your PD process?
(4) How do you select the design solution that will
be developed?
(5) How are your current processes and work
methods reviewed/improved?
10
M.S. Khan et al.
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(6) Do manufacturing (production) engineers play
an active role in each stage of PD?
(7) Do your suppliers provide you with multiple
alternatives for a single part (component)?
(8) How are projects currently initiated, and the
does the PD process flow?
The results show that a number of lean PD enablers
have been employed in the companies that were
studied. However, the companies have not formally
implemented the majority of lean PD enablers as can
be seen in Figure 4.
One company has formally implemented a setbased approach in the concepts stage of their PD,
considering multiple alternatives and performing
extensive simulation and prototyping. Two companies
have tested a set-based approach informally, but do
not progress alternatives sufficiently. However, none of
the companies intentionally delay their specification of
products and they tend to work in a constrained design
space that limits their innovation and prevents
convergence upon optimum designs. This means that
a SBCE process could be a significant contribution to
each of the five industrial partner companies.
Three of the companies employ a supplier strategy
in which some suppliers are interlocked with the
company, while others are given less flexibility to
design components. Suppliers to these companies do
not employ SBCE, but they do sometimes offer
alternative solutions based on a rough specification.
One company formally implements a chief engineer
system, wherein a technical leader is personally
involved in market research and is technically responsible for a product from concept to launch. However,
as in the other companies, a non-technical project
manager is always managing the project. Another
company has trialled this approach informally and
witnessed substantial results. Other companies do
employ technical leaders, but they tend to be appointed
after the concept stage or there are multiple leaders
Figure 4. Percentage of lean PD enablers that companies
A–E have formally implemented in their PD processes.
that lead different stages of PD. This implies that the
demonstration of consistent technical leadership for
the full product life-cycle could yield significant results.
All of the companies employ a systems engineering
approach with a combination of specification and
requirements documents. Cross-functional module
development teams are only employed in one of the
companies, however, they are formed late in the design
process. Manufacturing engineers tend to be involved
in the design of products and their level of involvement
increases as the project develops, however, only three
of the companies involve them in the concept stage
albeit minimally.
Knowledge tends not to be pulled, rather it is pushed
onto engineers; however, almost all interviewees suggested that most design problems would be solved if the
correct knowledge was in the right place at the right time.
It was also found that most of the interviewees spend
80% of their time on routine tasks, with the exception of
one company that puts special emphasis on innovation.
However, none of the companies focus primarily on
learning and increasing enterprise knowledge. Evidence
for the use of trade-off curves was found in one
company; however, checklists were employed in all
companies with varied usage and effectiveness.
Lessons learnt are captured by all of the companies, but are not used effectively. However, one
company has a formal lessons learnt strategy which
captures lessons from each project by employees who
are encouraged to make suggestions which are fed
back into the processes. The majority of interviewees
stated that they were always overburdened by the
quantity of work, with the exception of one company
where the engineers did not agree that this was the case
as opposed to the managers who thought it was.
A3 group problem solving is employed by two of
the companies during design, both of which follow a
PDCA learning cycle. One of these companies find it
difficult to follow as the meetings are generally virtual
and a single-sheet representation is not always used,
while the other company finds that different departments vary in their methodologies.
Mistake proofing is considered where possible in all
of the companies, but there is no evidence that it is
formally analysed as part of their PD processes. Design
for six sigma is used sometimes by three of the
companies to ‘design in’ quality to the designs, but it
is considered only somewhat effective by most. Robust
design and Taguchi methods are also used in two of the
companies.
It was found that at the systems level products
follow a drumbeat and are designed as part of a
strategy with different product types (redesign, major
modification, minor modification, facelifts, etc.). However, first tier suppliers respond to customer requests,
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International Journal of Computer Integrated Manufacturing
often in competition with other suppliers. Projects tend
to run late, and activities are often sacrificed in order
to meet launch dates. Only one of the companies has a
separate (dedicated) research department, which offers
mature technology to new products. Other companies
have research and development departments that push
their technology onto new products.
The results show that most of the lean PD enablers
have a presence in industry, but different companies
excel in the implementation of specific enablers. These
enablers tend to be developed in-house or imported
from a parent (or another) company and lack the
benefits of academic support. Many of the lean PD
enablers are intuitive, which explains their informal
application; however, participants suggested that
cultural and organisational barriers are likely to be
the main inhibitors. Another problem is the misunderstanding that lean PD is lean manufacturing applied to
PD. Once the participants were provided with information about lean PD, they were welcoming to the
new ideas, and they did, however, want to see the
results of a real case study before considering any
formal implementation. There remains a need for
generic and formal research-based methodologies,
techniques and tools to embed Lean PD enablers
into PD.
8. Conclusions and future work
This article provides the methodology adopted in order
to pave the way towards the development of a coherent
lean PD model that is fundamentally based on the
Toyota PD system. A systematic review has been
conducted in which the various approaches towards
lean PD have been analysed and categorised. Based on
the review, lean PD has been defined as follows:
‘Lean PD is value-focused PD. Value is a broad term
used to define stake-holder needs and desires. SBCE is
a strategic and convergent PD process guided by
consistent technical leadership throughout. SBCE
enables the focus on value and in particular knowledge
and learning. Continuous improvement is the culture
and an outcome of the SBCE learning process’.
Previous research provides minimal evidence of the
effectiveness of applying Toyota PD methods outside
of Toyota. One reason for this is that the area of
research is fairly new and has been overshadowed by
lean manufacturing and lean enterprise research.
Another possible explanation may be a cultural barrier
that inhibits the ideas of ‘left-shifting work’ and
developing multiple alternative designs instead of a
single design, which is the foundation of SBCE.
Further research is required to progress lean PD into
a discipline in its own right.
11
The building blocks of Toyota PD which support five
core enablers have been structured in a framework which
can be used as a reference for the key constituents of
Toyota PD, which is our best reference for lean PD. The
authors have collaborated with five engineering companies and conducted structured interviews in each of them
to search for evidence of the implementation of lean PD
enablers. Some of these enablers have been informally
applied in the companies, and a few have been formally
implemented. However, no PD model was found that
formally combines the enablers into a coherent whole.
This shows that there is a need to demonstrate the
conceptual LeanPPD model and assess its impact on
PD. If a lean PD model is developed which addresses the
current challenges faced by industry, companies may
consider adopting it. Through our interactions with
industry, we have identified a keen interest in the
combination of the core enablers. The companies did
not want to be provided with isolated tools; rather they
would prefer to implement lean PD using their existing
tools and techniques.
The impact of the individual lean PD enablers does,
however, needs to be investigated to determine their
effectiveness and relevance within a lean PD model.
Future work that is currently in progress involves
developing the LeanPPD Model based primarily on
the five core enablers. The model will facilitate the
integration of best practises from Toyota and other
companies that are best suited to support the core
enablers. Future research may also include the development and implementation of methods and tools that
support the hypotheses in this article. While this research
provides direction for developing a lean PD model,
organisational, human resource and cultural factors
need also to be considered as processes are implemented
by people.
Acknowledgements
The research presented in this article has been conducted
as part of a European project titled ‘Lean Product and
Process Development (LeanPPD)’. The project involves
multiple research and industrial partners from the UK,
Spain, Germany, Italy and Poland. The project is
supported by the Commission of European Community
(contract number NMP-2008–214090) under the NMP
Programme (Nanosciences, Nanotechnologies, Materials
and new Production Technologies). The authors acknowledge the European Commission for its support as well as
the other partners in the consortium (http://www.leanppd.eu).
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