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There are three distinct forms of maintenance,
these fit broadly into the following categories:
- Breakdown maintenance
- Periodic shutdown maintenance
- Condition based maintenance
Each strategy has its own merits but as shown below some are
potentially more costly than others.
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# 1 : Breakdown maintenance |
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Breakdown maintenance
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This form of maintenance is
simply “run to failure,” it allows no intervention
in plant operation, plant is maintained only when forced by
breakdown. This option certainly has the lowest capital outlay
on systems, it is, however, the most costly form of long term
plant maintenance.
Plant benefits
- Takes advantage of entire machine lifetime
Disadvantages
- Extensive resulting machine damage
- Fire fighting 24 hours - 7 days per week
- Large stock holding of expensive of spares is needed
- Long unplanned shutdowns necessary
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# 2 : Periodic shut down maintenance |
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Periodic shut down maintenance
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| This maintenance practice was once the industry
norm, every plant had a periodic shut down, machines were overhauled
and new components fitted irrespective of operating condition.
Plant benefits
- minor resulting damage to ancillary plant
- planned shut downs when convenient to the production
process
Disadvantages
- machine lifetime not fully used
- machines repaired to death
- parts replaced that do not need it
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# 3 : Condition based maintenance |
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Condition based maintenance
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| This is the most cost effective form of plant maintenance;
plant is monitored or repaired only according to diagnosed condition.
Plant benefits
- spare parts and repair according to condition - not
because it is scheduled
- no resulting machine damage to ancillary equipment
- uses entire machine life time
- service according to condition
- planned shutdowns
- production certainty
Disadvantages
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The high number of benefits shown for condition based maintenance
is not creative licence by Pruftechnik. Way back in 1988 the
DTI in a Boardroom report on maintenance practice in the UK
stated...
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"Industry
spends some £14 Billion per annum on plant maintenance
in the UK, money that is necessary but non-the-less a
drain on UK industry competitiveness.”
They found that...
"Companies who have implemented
a CM program on their plant on average spend 25% less
on maintenance of the plant than companies who have
no CM program.”
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