|
Dupont
analysis suggests that if companies focus on planning
only they will improve their uptime by 0.5%.
If they focus only on maintenance scheduling,
uptime will improve by 0.8%.
If they focus on preventive and predictive
maintenance only, uptime will actually get worse by
2.4%. If
organizations focus on all of these three aspects,
they will receive a 5.1% improvement in availability.
These
results may well sound appealing in their own right,
but Dupont (Ledet 1994)has found that by adding defect
elimination to the initiatives undertaken, then a
14.8% improvement in availability may be achieved in
their plants. This
information is provided in the table at Figure 2.
|
Strategy
|
Change
%
|
Uptime
%
|
|
Reactive
|
|
83.5%
|
|
Planning
Only
Scheduling
Only
Preventive
/ Predictive Only
|
+
0.5%
+0.8%
-2.4%
|
|
|
All
Three Strategies
|
+5.1%
|
88.6%
|
|
Plus
Defect Elimination
|
+14.8%
|
98.3%
|
Figure
2
Table showing the effect of different
reliability engineering activities on plant
availability taken from the Manufacturing
Game® – (Ledet 1994)
Problems
with most PM Programs
The
common problem with mature maintenance programs that
were never designed correctly in the first place, is
that between 40% and 60% of the PM tasks serve very
little purpose (Moubray, 1997).
The findings of many PMO reviews are that:
·
Many
tasks duplicate other tasks.
·
Some
tasks are done too often (and some too late).
·
Some
tasks serve no purpose whatsoever.
·
Many
tasks will be intrusive and overhaul based whereas
they should be condition based.
·
There
are many costly preventable failures happening.
This
poses a significant issue for improving productivity
as no amount of perfect planning and scheduling will
make up for the inefficiencies of the maintenance
program itself. Achieving
100% compliance with a program that is 50% useful and
50% wasteful can not be good asset management!
The
Dupont analysis indicates that a process must be
implemented that:
·
Can
define the appropriate mix of preventive and
predictive maintenance,
·
Can
produce a maintenance program where the servicing
intervals and the tasks themselves are sound and value
adding in every case, and
· Where
defects which can not be maintained out of the plant
can be eliminated through other means.
What
is suggested, as a fundamental building block in
adopting all these strategies, is to ensure all work
undertaken is based on RCM decision logic.
PMO is a means of rationalizing all the
Preventive Maintenance work to ensure that all the
work adds value and there are no duplications of
effort. Figure
3
illustrates this.
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