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| The 7 Manufacturing WastesAugust 29, 2003 Waste elimination is one of the most effective ways
to increase the profitability of any business. Processes either add
value or waste to the production of a good or service. The seven wastes
originated in Japan, where waste is known as “muda." "The seven
wastes" is a tool to further categorize “muda” and was originally
developed by Toyota’s Chief Engineer Taiichi Ohno as the core of the Toyota
Production System, also known as Lean Manufacturing. To eliminate waste, it is
important to understand exactly what waste is and where it exists. While
products significantly differ between factories, the typical wastes found in
manufacturing environments are quite similar. For each waste, there is a
strategy to reduce or eliminate its effect on a company, thereby improving
overall performance and quality. The seven wastes consist of: 1.
Overproduction. Simply
put, overproduction
is to manufacture an item before it is actually required.
Overproduction is highly costly to a manufacturing plant because it
prohibits the smooth flow of materials and actually degrades quality and
productivity. The Toyota Production System is also referred to as “Just in
Time” (JIT) because every item is made just as it is needed. Overproduction
manufacturing is referred to as “Just in Case.” This creates excessive lead
times, results in high storage costs, and makes it difficult to detect defects.
The simple solution to overproduction is turning off the tap; this requires a
lot of courage because the problems that overproduction is hiding will be
revealed. The concept is to schedule and produce only what can be immediately
sold/shipped and improve machine changeover/set-up capability. 2.
Waiting Whenever
goods are not moving or being processed, the waste of waiting occurs. Typically
more than 99% of a product's life in traditional batch-and-queue manufacture
will be spent waiting to be processed. Much of a product’s lead time is tied
up in waiting for the next operation; this is usually because material flow is
poor, production runs are too long, and distances between work centers are too
great. Goldratt (Theory of Constraints) has stated many times that one hour lost
in a bottleneck process is one hour lost to the entire factory’s output, which
can never be recovered. Linking processes together so that one feeds directly
into the next can dramatically reduce waiting. 3. Transporting Transporting
product between processes is a cost incursion which adds no value to the
product. Excessive movement and handling cause damage and are an opportunity for
quality to deteriorate. Material handlers must be used to transport the
materials, resulting in another organizational cost that adds no customer
value. Transportation can be difficult to reduce due to the perceived costs of
moving equipment and processes closer together. Furthermore, it is often hard to
determine which processes should be next to each other. Mapping product flows
can make this easier to visualize. 4. Inappropriate
Processing Often
termed as “using a sledgehammer to crack a nut,” many organizations use expensive high precision equipment where
simpler tools would be sufficient. This often results in poor plant layout
because preceding or subsequent operations are located far apart. In addition
they encourage high asset utilization (over-production with minimal changeovers)
in order to recover the high cost of this equipment. Toyota is famous for their
use of low-cost automation, combined with immaculately maintained, often older
machines. Investing in smaller, more flexible equipment where possible; creating
manufacturing cells; and combining steps will greatly reduce the waste of
inappropriate processing. 5.
Unnecessary
Inventory Work
in Progress (WIP) is a direct result of overproduction and waiting.
Excess inventory tends to hide problems on the plant floor, which must be
identified and resolved in order to improve operating performance. Excess
inventory increases lead times, consumes productive floor space, delays the
identification of problems, and inhibits communication. By achieving a seamless
flow between work centers, many manufacturers have been able to improve customer
service and slash inventories and their associated costs. 6. Unnecessary
/ Excess Motion This
waste is related to ergonomics and is seen in all instances of bending,
stretching, walking, lifting, and reaching. These are also health and safety
issues, which in today’s litigious society are becoming more of a problem for
organizations. Jobs with excessive motion should be analyzed and redesigned for
improvement with the involvement of plant personnel. 7. Defects Having a direct impact to the bottom line, quality defects resulting in rework or scrap are a tremendous cost to organizations. Associated costs include quarantining inventory, re-inspecting, rescheduling, and capacity loss. In many organizations the total cost of defects is often a significant percentage of total manufacturing cost. Through employee involvement and Continuous Process Improvement (CPI), there is a huge opportunity to reduce defects at many facilities. In the latest edition of the
Lean Manufacturing classic Lean Thinking, Underutilization of
Employees has been added as an eighth waste to Ohno’s original seven
wastes. Organizations employ their staff for their nimble fingers and
strong muscles but forget they come to work everyday with a free brain. It is
only by capitalizing on employees' creativity that organizations can
eliminate the other seven wastes and continuously improve their performance. Many changes over recent years have driven organizations to become world class organizations or Lean Enterprises. The first step in achieving that goal is to identify and attack the seven wastes. As Toyota and other world-class organizations have come to realize, customers will pay for value added work, but never for waste. Click here to subscribe to our free e-newsletter Learning to Lean and receive three articles like this one each month. About
the Author David McBride is co-founder of EMS Consulting Group (http://www.emsstrategies.com), a Carlsbad, CA based engineering and management consulting firm. David has a BS in Mechanical Engineering from Ohio State University. He has a successful track record in the development and implementation of FMEA and Design for Manufacturability programs at several organizations and has greatly reduced Manufacturing costs through the utilization of Lean Manufacturing, Kaizen Events, and Manufacturing System Analysis. He has also been highly successful at developing and executing New Product Introduction processes, and Staffing and Capital Equipment Plans. | ||||||||||||||
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