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9
Lean Manufacturing
Overview
In the last chapter, we introduced the concept of a visual factory as a fundamental
approach to improvement. In this chapter, we will discuss the notion of removing
waste (nonvalue activities) not only from individual processes but also from the
entire organization. The terminology for this methodology is Lean manufacturing.
Even though the consensus is that Lean manufacturing as applied today
is derived from Toyota’s principles of Lean production methods, the roots of
the process are in Henry Ford’s integrated philosophy in the Rouge Complex
in Dearborn, Michigan, in the early 1900s. The difference between Ford’s
approach and Toyota’s is that Ford’s method was static, whereas Toyota’s
became a dynamic process.
The term Lean manufacturing was coined by Krafcik (1988) and made popu-
lar by Womack, Jones, and Roos (1991). If the reader is interested in more details
about the history of Lean, Holweg (2007) gives a complete historical account.
The reader will notice that we identied Lean as a methodology and not a
tool. That is because Lean incorporates many tools to accomplish its mission,
which is elimination or reduction of waste—however dened. Some of these
tools are Single Minute Exchange of Dies (SMED), Value Stream Mapping
(VSM or VM), 6S, Kanban (pull system), Poka yoke (error/mistake proof-
ing), Total Productive Maintenance (TPM), rank order clustering, Statistical
Process Control (SPC/control charts), redesigning working cells, multipro-
cess handling, single point scheduling, and many others.
In essence, these and many other tools within Lean are implemented with the
intention of increasing quality while at the same time reducing production time
and costs. This is accomplished by separating the waste (muda) into three catego-
ries, which are based on Toyota’s system of preventive maintenance. They are
1. Muda (non-value-adding work). Focusing on the system, not reduc-
tion per se in individual pockets of a process. Generally, it is a reactive
activity of identifying waste and is seen through variation in output.
2. Muri (overburden). Focusing on the preparation and planning of the
process, or what work can be avoided proactively by design.
104 Quality Assurance
3. Mura (unevenness). Focusing on production leveling by utiliz-
ing a pull system such as the Kanban or the Heijunka box (SMED)
approaches. This focus is predominantly on how the work design is
implemented and the elimination of uctuation at the scheduling or
operations level, such as quality and volume.
To recognize and do something about these wastes, management must
take an active role. Its basic role is to examine the muda in the processes and
eliminate the deeper causes by considering the connections to the muri and
mura of the system. The muda and mura inconsistencies must be fed back to
the muri, or planning, stage for the next project. To optimize this link, there
are several assumptions that must be considered so that the three categories
of waste will work. The assumptions are
1. Pull processing
2. Perfect rst-time quality
3. Waste minimization
4. Continuous improvement
5. Flexibility
6. Building and maintaining a long-term relationship with suppliers
7. Autonomation (the basic idea of jidoka ) may be described as
intelligent automation or automation with a human touch
8. Load leveling
9. Production ow (just-in-time, JIT)
10. Visual control
In essence, the results of understanding these three waste categories are to
get the right things to the right place at the right time in the right quantity
to achieve perfect workow, while minimizing waste and being exible and
able to change. In order for that exibility and change to take place within an
organization, they have to be understood, appreciated, and embraced by the
actual employees who build the products (or carry out the service) and there-
fore own the processes that deliver the value. It is of paramount importance
that in addition to the employees being on board with the implementation
process, the culture and management of the organization must be ready to
embrace the change enthusiastically and be committed to removing waste.
It is worth mentioning here to practice Toyota’s mentoring process of Sempai
(senior) and Kohai (junior), which has proved to be one of the best ways to
foster Lean thinking up and down the organizational structure—including
suppliers. Without a strong commitment, nothing will happen in the end.
Womack and Jones (1996) suggest an additional strategy for encouraging
companies, organizations, and teams to seek outside, third-party experts, who
can provide unbiased advice and coaching via the concept of a Lean Sensei.
105Lean Manufacturing
Lean Goals and Strategy
It is very interesting to note up front that the goals of Lean manufacturing
systems differ between various authors and in some cases organizations.
The main differences are on the perspective of how Lean is viewed. Some see
it as an internal methodology to the organization to increase prot. Others
see it as a methodology focusing on improvements that should be under-
taken for satisfying the customer.
While some maintain an internal focus, for example, to increase prot
for the organization (Liker 2004, Feld 2001, Ohno 1988, Monden 1998,
Schonberger 1982, Shingo 1984), others claim that improvements should be
done for the sake of the customer (Womack et al. 1990, Womack and Jones
2003, Bicheno 2004, Dennis 2002, Schonberger 1982).
However, whatever the perspective, everyone agrees on the fundamental
goals and strategy of Lean, which are to
1. Improve quality: An inherent characteristic to stay competitive in
today’s marketplace. This is very important in today’s globalization
endeavors because unless an organization understands its custom-
ers’ wants, needs, and design processes to meet their expectations
and requirements, they will fail in the market.
2. Eliminate waste: In order to improve quality, one must understand
and eliminate waste. Waste is any activity that consumes time,
resources, or space but does not add any value to the product or ser-
vice. In statistical terms, waste is variation. Therefore, as we reduce
variation, we shrink the waste.
Therefore, in order to improve quality by any metric, one must address
waste. Waste is diminished by at least focusing on the two following areas:
1. Reduce time: This means reducing the time it takes to nish an activ-
ity from start to nish is one of the most effective ways to eliminate
waste and lower costs. It is indeed the cycle time.
2. Reduce total costs: This means to minimize cost. A company must
produce only to customer demand. Overproduction increases a
company’s inventory costs because of storage needs.
When one discusses waste, one is reminded of the original seven deadly
wastes dened by Ohno (1988) as part of his Toyota Production System (TPS)
and reported by Womack and Jones (2003, 352). The original wastes are
• Transport (moving products that are not actually required to per-
form the processing)
106 Quality Assurance
• Inventory (all components, including work-in-process and nished
product not being processed)
• Motion (people or equipment moving or walking more than is
required to perform the processing)
• Waiting (waiting for the next production step, interruptions of pro-
duction during shift change)
• Overproduction (production ahead of demand)
• Overprocessing (resulting from poor tool or product design creating
activity)
• Defects (the effort involved in inspecting for and xing defects)
As time passed, more wastes were added, which are described as man-
ufacturing goods and services that are not necessarily meeting customer
demand or specications. They include waste of unused human talent. For
example, in the Six Sigma methodology, waste of skills is identied as a
waste and is referred to as underutilizing capabilities and delegating tasks
with inadequate training (Stamatis 2003, 2004). Space is also recognized as a
waste (Stamatis 2011).
Mika (1999, 2006) added three more forms of waste that are now univer-
sally accepted: (1) the waste associated with working to the wrong met-
rics or no metrics, (2) the waste associated with not utilizing a complete
worker by not allowing him or her to contribute ideas and suggestions
and be part of participative management, and (3) the waste attributable
to improper use of computers, that is, not having the proper software,
training on use, and time spent surng, playing games, or just wasting
time. For a complete listing of the “old” and “new” wastes, see Bicheno
and Holweg (2008).
The strategic elements of Lean can be quite complex and comprise multiple
elements. Out of this complexity, Pettersen (2009) has been able to identify
four distinct notions of Lean. They are
1. Lean as a philosophy (Lean thinking)
2. Lean as a continuous change process (becoming Lean)
3. Lean as a xed state or goal (being Lean)
4. Lean as a set of tools or methods (doing Lean/toolbox Lean)
Steps to Achieve Lean Systems
As it was mentioned earlier, Lean is a methodology and it takes time to be
implemented in any organization. There have been many suggestions and
107Lean Manufacturing
recommendations in the literature as to how to go about introducing, imple-
menting, and sustaining Lean in a given organization. Here we are going to
summarize the approach that Womack and Jones (1996, 247–271) have sug-
gested and a much later approach recommended by Akinlawon (n.d.). In
both cases, we recognize there are limitations, but we believe they are some-
what the extreme approaches. Individual organizations may adjust these to
t their own cultures and timing.
In both cases, the organization must be willing to change the culture and
that may take longer than some as the change agents are either experienced
or committed and involved in the process of change. A second prerequisite
is for management not to focus on a policy of quick xes but rather to under-
stand the real change at hand and build a solid foundation for improvement
using Lean.
The recommended approach by Womack and Jones is very lengthy and
time consuming as they assume that the organization starts from ground
zero. Their approach is the following:
1. First 6 months: This is where the organization begins. It means to
nd an appropriate change agent, educate the organization with
Lean knowledge, map value stream, expand the knowledge as
appropriate, begin focusing on both fundamental as well as radical
changes to a production system (your operating system or a service
system), and dene the scope.
2. Six months to Year 2: This is the beginning of the new transforma-
tional change of the organization. It means organize or reorganize
categories of products, create a Lean function based on the value
mapping, dene a policy for excess workers, dene a growth strat-
egy, and instill a zero defect (perfection) mind set.
3. Years 3 and 4: This is the time period for installation of the business
systems to make a difference. It means a new process for accounting,
change base payment to performance metrics, implement transpar-
ency, make sure the appropriate and applicable tools are available
to the workers, demonstrate Lean successes, continue Lean train-
ing, and initiate policy deployment to encourage Lean approaches
throughout the organization.
4. By the end of Year 5: This is where the transformation is com-
plete and functioning. It means the beginning of cascading the
principles of Lean to your customers and suppliers, developing
global strategy, if applicable, and making sure that the transfor-
mation of change is driven by bottom-up rather than top-down
improvement.
On the other hand, Akinlawon (n.d.) approaches the implementation from
a holistic perspective. His focus is not so much on the timing but rather the
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