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The Seven
Wastes To Be Eliminated |
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Overpoduction
and early production – producing over customer
requirements, producing unnecessary materials / products
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Waiting – time delays, idle time
(time during which value is not added to the product)
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Transportation – multiple handling,
delay in materials handling, unnecessary handling
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Inventory – holding or purchasing
unnecessary raw materials, work in process, and finished goods
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Motion – actions of people or
equipment that do not add value to the product
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Over-processing – unnecessary steps
or work elements / procedures (non added value work)
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Defective units – production of a
part that is scrapped or requires rework.
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Toyota's Holistic Approach To Waste
Elimination
Wastes (muda)
are the
activities and results to be eliminated.
While the elimination of waste may seem like a
clear subject in such environmental concepts as
cleaner production,
it is noticeable that waste is often very conservatively identified. This
then hugely reduces the potential of such an aim.
In
Lean Manufacturing,
waste is any activity that consumes time, resources, or space but does not
add any value to the product or service.
Lean manufacturing is, in its most basic form, the systematic
elimination of 7 wastes – overproduction,
waiting, transportation, inventory, motion, over-processing, defective units
– and the implementation of the concepts of continuous flow and customer
pull.
A finer clarification of waste is key to
establishing distinctions between value-adding activity, waste and
non-value-adding work. Non-value adding work is waste that must be done
under the present work conditions. One key is to measure, or estimate, the
size of these wastes, to demonstrate the effect of the changes achieved and
therefore the movement toward the goal.
The "flow" (or smoothness) based approach aims
to achieve Just -In-Time (JIT), by removing
the variation caused by work scheduling and thereby provide a driver,
rationale or target and priorities for implementation, using a variety of
techniques. The effort to achieve JIT exposes many
quality problems
that are hidden by buffer stocks; by forcing smooth flow of only
value-adding steps, these problems become visible and must be dealt with
explicitly.
Kaizen
Culture: 8 Key Elements
The
Three Broad Types of Waste
The elimination of waste is the goal of
Lean.
Toyota
defined
three broad types of waste: muri, mura and
muda.
The Toyota Way: 14 Principles
Muri is all the unreasonable work that management imposes on
workers and machines because of poor organization, such as carrying heavy
weights, moving things around, dangerous tasks, even working significantly
faster than usual. It is pushing a person or a machine beyond its natural
limits. This may simply be asking a greater level of performance from a
process than it can handle without taking shortcuts and informally modifying
decision criteria. Muri also includes bad working conditions, and it will
often push a resource to work harder than its natural limits. Unreasonable work is almost always a cause of multiple
variations.
Mura is the variation and
inconsistency in quality and volume in both products and human conditions.
Muda is the Japanese word for
waste.
It specifies it specifies any human activity, which absorbs resources, but
does not directly add
customer value.
These non-value-adding
activities and results
– overproduction, waiting, transportation, inventory, motion,
over-processing, defective units –
are to be eliminated.
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