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The Toyota Production System (TPS), also known as the Toyota
Way or Lean Production, can be traced back to the 1950s,
when Japan's post-war manufacturing industry saw
double-digit growth fueled by the strong demand for
industrial goods as a result of growing markets, both
domestic and overseas, coupled with the Korean War. Taiichi
Ohno (1912- 1990), a production engineer who early on rose
to one of Toyota's executives, is credited for systematizing
the company's production management system.
The pillar of TPS is an uncompromising pursuit for waste
reduction (as characterized in the Lean Methods, Just In
Time, and Kanban Systems) and a production system built on
incremental improvements that repetitively outputs
defect-free products (Kaizen, QC Circles, etc.). In Japan,
the ruthless pursuit for waste and cost reduction is often
dubbed by their suppliers and media as "wringing moisture
out of a dry towel."
TPS largely concerns production and manufacturing
activities. The story that Toyota's line workers are
empowered to stop an entire assembly line when they discover
a problem is the epitome of this approach. Interestingly,
unlike many QC Circle stories that their blue collar workers
and supervisors are encourage to report in annual
conventions, one rarely hears about TPS by upper management
or design engineers, although this could be something to do
with the way the company guards its trade secrets.
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When Drs. Akao and Mizuno developed QFD in the
1960s, many TPS techniques were already recognized
as Japanese Total Quality Control (TQC) methods.
What Akao and Mizuno set to achieve was a
customer-focused New Product Development (NPD)
system that captured and built in end user needs and
quality requirements before manufacturing began. The
name, Quality Function Deployment (QFD) ,
came from the fact that this new quality system
aligns different organizational functions on a
common goal of satisfying the customer. It requires
cross-functional teams and departments to work
together in incorporating customer needs from
upstream NPD planning to production output and
after-sales customer care.
In Comprehensive QFD, Akao systematized this
approach to encompass every aspect of business and
organizational management. It was the first quality
system to directly link the operational quality
(design and manufacturing designers, project
members, sales staff, etc.) and management quality
(R&D, Administration, Business Development and
Planning, etc.). Through this aligned and linked
approach, dots are connected and made visible across
the divides of physical walls and organizational
territories. This is why companies who have been
doing traditional quality methods for many years and
even Six Sigma are finding QFD quite useful in
today's more complex business environment.
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For example, at Kawasaki Heavy Industry
(manufacturer of Japan's Bullet Trains, airplanes,
industrial robots, etc), their traditional quality
assurance activities focused on preventing
recurrence of manufacturing quality problems. QC
Circles on the plant floors, as touted in TPS, were
typical of such efforts. Subsequent analysis
revealed, however, that the majority of the quality
problems reported after product delivery could be
traced back to issues originating in the upstream
processes such as Design, Contract, Procurement,
etc.
The new revelation came as a shock to the company's
management because they had been a leader in the
zero defect movement and had been doing traditional
quality control for many decades. "With so much
quality efforts already taken, what are we missing?
How can we make the engineers and contract
administrators, who are in the forefront of the NPD
process, see that they, too, need quality awareness?
What tools can they use?" This turned the company's
eyes to QFD in 1994.
Kawasaki began teaching QFD top down, beginning with
the senior management level so they could support
the efforts of downstream project teams. Over the
years, the company expanded the QFD training to its
engineers, managers, project team members, and
eventually the front line hourly-waged factory
workers and support staff. At the
1996 International Symposium on QFD, a Kawasaki
presenter shared how all these QFD matrices became
useful not only in planning the next generation
products, but also in tracing back errors and
deficiencies in the process, material, production,
technology, and even communication in case of a
post-launch quality problem.
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In Reliability Deployment, methods such as TPS, FMEA
(Failure Mode and Effects Analysis) and FTA (Fault
Tree Analysis) are used to identify possible failure
modes and preventive measures, with focus on
compliance to engineering specs set for product
functions and manufacturing/production processes.
For example, a Brazilian steel company made good use
of QFD Reliability Deployment after the
product was launched in the market and they received
the first wave of complaint data from customers.
Using the FMEA table, which nested in one of the
House of Quality matrices, each characteristic of
the product related to the complaints (low internal
yields, in this case) was examined. |
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A negative Characteristic Deployment matrix was
constructed. With this, a Fault Tree Deployment was
produced for the entire process relevant to the
identified characteristics. The weight of the
characteristics was then recalculated, taking into
account the customer complaints, internal yields,
and the importance derived from the Quality Matrix.
By crossing these matrices within a QFD framework,
the company was able to understand the location of
critical process issues with respect to quality.
This FMEA exercise was later used locally to improve
selected processes (the table above). Note, however,
improper calculation of an RPN from ordinal scores
is a separate issue.
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In the
2003 International Symposium on QFD, it was
reported that Japanese automakers had reduced the
typical development time by 50% over the previous 8
years. As automakers face increasing global
competition, wrong thinking about cost, i.e.,
carmakers' too much emphasis on cost reduction at
the expense of suppliers' ability to maintain
quality, could lead to quality problems including
costly recalls, pointed out an
automotive consultant from Japan.
He also warned to watch out for quality problems
when new technology or new business methods are
introduced: "Continued advancements in
modularization have resulted in part and equipment
suppliers being responsible for not only their
products but also for new functions of those modules
for which they are equipped." Add to that,
"increasing computerization has contributed to
products performing new functions or having new
structures, and such rapid, radical changes to
function and structure could raise new quality
problems." He proposed using QFD to prevent such
failures; below is one example of Design FMEA.
(Click the graphic to view the entire table in a PDF
file). |
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Like Reliability Deployment, Comprehensive QFD also
has a Safety Deployment. While commonly used
in health and medical related QFD studies, it is
important in manufactured goods as well. Common
factors in safety deployment are hygiene,
toxicology, automatic cut-off systems (to prevent
run-away operation), electrical shock, traumatic
injury, etc.
Given recent reports alleging safety issues in
children's toys, automobile acceleration/braking,
and others, QFD practitioners are encouraged to
consider adding Safety Deployment.
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