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 Total
Productive Maintenance is often presented as a series of pillars
supporting Lean Manufacturing and resting on a foundation of
education and training. Below this is the attitude of
environmental responsibility and safety. Figure 5 illustrates. This representation is
adequate as a starting point. However, TPM, like Lean itself, is a
dynamical system and cannot be fully understood with a static model.
Supporting Lean
Maintenance enables and supports Lean efforts in at
least three major ways: Quality, Setup Reduction (SMED) and
predictability. In turn, other Lean elements support TPM through
Workcells, Teamwork and Problem-solving.
The Foundations
Education & Training-- Education, training and investments in people
characterize all aspects of Lean. In the maintenance area, they are
even more important because of the specialized knowledge required on
typical manufacturing equipment. This is one of the foundation
stones of TPM. Without it, the pillars of TPM will have limited
impact.
Safety/Environment-- Underlying even the training and education piece are
the more fundamental values of responsibility to the
environment and safety for employees. One important reason is simple: it is the right thing to do.
A more pragmatic reason involves motivation. Most people want to be a part of something larger than
themselves; appeals to higher motivation bring involvement and
commitment. It is difficult to argue against safety and a common
commitment to safety can be a bond that brings people together
on other issues.
Figure 5 the Pillars of TPM
Autonomous Maintenance
Autonomous maintenance is the concept that the
people
who operate a machine should maintain the machine. The degree of
autonomous maintenance depends on the level of training and the
abilities of operators. It often starts with basic lubrication,
cleaning and inspection and then graduates to minor or even major
repairs.
For example, in the foundry where this author worked,
machinists repaired and overhauled their own machine tools. A
trained and competent machinist is certainly capable of overhauling
a gearbox. And, as the users, they tended to know the equipment
intimately. In the military, everyone cleans their own weapon. When
their life depends on proper functioning, people take more
care.
Autonomous maintenance frees resources in the
maintenance department for the other activities such as equipment
improvement or major overhauls. It amplifies the maintenance efforts
and involves the operators who then take better care of the
equipment.
Planned Maintenance
Figure 6 Planned Maintenance
 Planned maintenance is the
deliberate
planning and scheduling of maintenance activities as opposed to reacting to
breakdowns and emergencies. A maintenance department that uses TPM
effectively generally devotes less than 10% of its labor hours to
such unplanned activities.
 Without TPM it is not unusual for 80%-90%
of the labor to be unplanned. Unplanned maintenance is a strong indicator that
prevention and improvement programs are non-existent or
ineffective. In addition, high percentages of
unplanned
maintenance creates problems. For eaxample:
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Huge inefficiencies in maintenance labor.
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Confusion and disturbance in scheduling, production and other areas.
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Morale problems.
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Equipment Improvement
Improving equipment
constantly is a major part of TPM.
This author witnessed an outstanding example of this some years ago
at Toyota's Kamigo Engine plant. Toyota was using the same type of
American equipment that I had seen at Ford Motor Company years
earlier. However, Toyota's equipment was so reliable that it ran
with far fewer people and far better quality. For more on this see
Kamigo engine Plant, 1985.
Most production equipment has not had the extensive
design, testing and development common in mass-produced products
such as automobiles. Accordingly, there are many deficiencies that
may not be evident when the equipment first goes into service. In
addition, each manufacturing plant and its products tends to be
different and can benefit by design changes that adapt the machines
better to their individual situations.
Older equipment does not necessarily have to be
replaced. In many cases, it can be upgraded and overhauled and made
better than new. In our steel foundry, we did this with fourteen of
our overhead cranes. Some were upgraded and re-rated for heavier
capacity. All were fitted with new controls, structural deficiencies
were fixed and the cranes made better than new. Several of these
cranes were over 45 years old.
Figure 7 Rebuilt & Improved Overhead Crane
New Equipment Management
New equipment management is related somewhat to
equipment improvement. It refers to the careful design, selection and
testing of equipment. The purpose is to ensure a smooth
commissioning process with minimal design defects and problems. New equipment management includes vendor selection,
evaluating options for maintainability, training personnel in
advance and other common-sense techniques.
Figure 8 Startup Of No-Bake
Foundry
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Debugging Rollover |
First Pour |
Process Quality Management
In TPM making
the equipment run is only part of Maintenance's job. Ensuring that the equipment is capable of
producing parts well within the tolerance range
(process capability)
is also a primary responsibility.
Worn bearings and ways, undo vibration, bent shafts
and multiple other maintenance problems contribute to the gradual
deterioration of process capability. With constant use, machines
still run but become "finicky." For example, a particular machine
shop lathe that the author recalls could only be run by a particular
operator. He was the only one who knew exactly where the ways were
worn and how to compensate.
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