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These are the best conditions for the operation and the maintenance
of the equipment’s capabilities or features to achieve World Class Maintenance, in such a way that the equipment
can be reliable for an optimal period of time.
There are necessary conditions: those that are the minimum
requirements for the operation of the equipment.
There are desirable conditions, those that surpass the standard
levels of operation. These last ones are also known as optimal, although
they are not indispensable.
This reasoning can help us to define the optimal
conditions:
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The
dimensional precision. Were the parts or components measured and manufactured
with accuracy?
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External
appearance. What is it the visible external condition of the parts and unit as a
whole?
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Precision
of assembly. Are all the parts and components correct? Are they well tightened
or adjusted?
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Precision
of installation. Is the machine firm in its place?
Is it well-leveled?
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Operational
Precision. Is the reality comparable to the optimal? Is the result good and
repetitive when operating the machine?
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Functional
parts. Are they compatible with the equipment or system? Are they well-adjusted?
Are the hydraulic seals compatible with the oil that is being used?
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Environment.
Is it acceptable for the equipment? Humidity,
temperature, exposure to the dirt, powders, rain, ventilation, pollutants…? Do
specifications exist?... if not, get them!
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Strength.
Quality or characteristic of the materials. Is the material appropriate? Is
there some more durable? Is there insufficient, excessive or appropriate
hardness?
The optimal conditions should be known to discover the faulty conditions
where improvements are needed. The basic conditions are shown in manuals,
drawings and technical information, sometimes in parts lists, assembly
instructions and installation manuals. It
is vital to preserve these documentation pieces in a secure place accessible so
that copies of all them are provided to the operators and maintenance personnel.
In some cases, it will be necessary to educate and train personnel for the
appropriate interpretation of that information. According to the new
disciplines, this kind of information should no longer be a secret, as it was in
the past.
In order to define the optimal conditions and to establish certain limits,
it will sometimes be necessary to apply the trial and error procedure, or to
simulate conditions to expose hidden defects. (What would happen if...?)
Obviously, safety measures should be carried to an extreme when doing
this.
Among
the main expenses in the maintenance of industrial plants are the
small/recurrent defects. They seldom cause failure by themselves, but they
certainly contribute to other failures. Dust, dirt, vibration, minimum leaks
fall into this category. Therefore the importance of the periodic process of:
cleaning, lubrication and inspection.
The
objective of focusing on these minimal defects is preventing the bigger problem
of them accumulating, since they can end up causing serious failures.
No
analysis or speculation guarantees the identification of which defects can cause
which problems. The solution is to eliminate all the possible defects. It is
necessary to follow two principles:
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Evaluate the
relationship between the nature of the equipment and the minimal defects from a
logical point of view, and to review the related factors and the basic
principles.
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Don’t get
distracted and keep in mind that the probability that a simple defect
contributes to a serious problem tends to be minimized. Any defect, even small,
should be eliminated as soon as it is detected.
The
root cause analysis is a technique developed to promote the complete and
systematic elimination of the defects that contribute to losses from chronic
failures. By means of this process, all the components that contribute to the
failures and chronic losses are identified and eliminated, following a simple
procedure that has been described by several experts in diverse publications and
even some computer programs:
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1. Clarify the problem.
Carefully investigate the problems and compare
their appearance, conditions, and affected parts with those of similar
equipment. This way we make sure that the problem is the same one in all the
cases (typical) or it is isolated. Ask the operators about what they have seen,
listened, smelled or felt previous to the problem. That information can help
avoid its recurrence. Definitively, in these cases the benefit of the basic
training of the operators in the knowledge of the equipment will be evident.
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2. Physical Analysis of the problem.
Consider how the physical
conditions such as: lack of cleanliness, obstructions, contamination can be
causing the observed problem. Review all apparent basic causes, as well as
actions that have been taken in previous occurrences of the problem. Developing
a diagram can in certain cases be very practical. Let us keep in mind that
almost always a cause can be the effect of another cause. This process forces us
to continue deeper until finding the true original cause or Root Cause.
It is good investment of time. We all learn more. Always invite the operators to
participate in this investigation.
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3. Register
each possible action or condition that can be related with the problem.
Consider what conditions should be present for the problem or abnormality to
take place or to reproduce. Maybe it only happens during the last hours of the
shift, or only on third shift. Also in some occasions it happens only in a
certain time of the year. The causes can be related with the climate, the
operation style, temperature or humidity and many other variables.
See diagram of causes...
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4. Evaluate the equipment,
the materials and the process. Consider conditions identified in the step 3,
have direct relationship with the equipment, tools used, material that are being
worked and the processes or methods involved. List among them the factors that
influenced the problem.
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5. Plan the investigation.
Carefully plan the action and investigate each
factor. Decide what should be measured, how to measure it and select how to take
advantage of the obtained measurements.
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6. Investigate the operation failures.
All that was planned in
the step 5 should be totally investigated. Have in mind the good conditions to
be confirmed and the influence of light defects. Make sure they are included in
the daily inspection list.
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7. Formulate improvement plans.
Based on the investigations, plan and develop the
improvement strategies for each case. Include in these plans the priority of the
proposals that the operators and the maintenance technicians may have.
There
may be as many causes per level and as many levels as necessary, eliminating one by one, until arriving to
the correct Root Cause. It should be documented, because the possibility exists
that it may happen in another similar piece of equipment. An inspection should
be scheduled for those other machines or pieces of equipment.
The most important: Follow-up
and thorough training to users and maintenance techs should be given so that the cause doesn't repeat.
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