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JAINAM MEHTA, PUNIT RUGHANI,VIRENDRA
▶ Maintenance is defined as that function of production management
concerned with the day to day problem of keeping the physical plant in
good operating condition.
▶ Plant maintenance usually refers to the methods, strategies, and
practices used to keep an industrial factory running efficiently. This can
include anything from regular checks of equipment to make sure they are
functioning properly, to cleaning garbage bins and toilets. The general aim
of plant maintenance is to create a productive working environment that
is also safe for workers.
Plant maintenance is concerned with actions taken
by the plant user to maintain an existing system and
facilities or to restore it to an operating condition.
▶ Maintenance of plant, building,
machinery and equipments plays an
important part in determining the
life expectancy of physical assets.
The actual service lives may be
lengthened considerably by a good
The purpose of plant maintenance is usually secondary, however to the need
for keeping industrial building and their equipment and good working order.
Therefore, the objectives of maintenance are twofold:
a) To keep the plant in working conditions.
b) To arrest depreciation and forestall obsolescence.
“Maintenance in the industrial plant is the upkeep, repair,
renewal and replacement of worn, damaged or obsolete parts
of building, machinery and equipments.”
▶ Maintenance may be preventive. Preventive maintenance implies frequent
inspection to detect minor faults and the early correction of them, so that
the possibility of a major breakdown is almost entirely eliminated.
▶ Corrective maintenance implies that action is taken only when the need for
it becomes obvious and, therefore, gives no assurance that a major
breakdown will not occur.
▶ Most plants use both types of
maintenance, where a major defect
in one of the building, or in a vital
machine, would be seriously
reduced or completely stop
production, or preventive
maintenance program is indicated.
▶ Since there are many different types of plants and factories, the
ways to maintain these facilities often vary. For example, a steel
mill will have different machinery than a food processing plant. This
means that each place of business generally has its own maintenance
plan, tailored to its particularities. A maintenance plan can include
scheduling times for equipment checkups, trouble-shooting, and
Continue.. ▶Most plants employ their own maintenance
staff. This can include workers such as on-site
engineers, whose job is to make sure that
machines continue to operate effectively. This
is an especially important for plants that use
equipment designed for assembly lines, since a
stoppage of the line can be financially
▶ Is concerned with those actions taken by a
system and facilities during development so that
the system or facilities when installed and
operated can be maintained with ease.
▶ Maintainability means design for ease of
maintenance. It is the characteristic of system
design which determines the ability of a system
to be retained in or restored to an effective
operational condition. It is concerned with the
system’s down time. It include aspects such as:
▶ Incorporation of fail safe features
▶ Tolerance which allows for wear through machine life
▶ Selection of materials that ensure minimum failure due
to fatigue and friction
▶ Reliability is defined as the probability of a
plant to give satisfactory performance in a
particular period of time under specified
conditions. The time between failures is
▶ Availability is the percentage of time the
machine will be available for operation
▶ Availability = Mean Time Between
MTBF + Mean Time for
▶ Plant protection ( including fire fighting)
▶ Waste disposal
▶ Pollution and noise reduction
▶ Sanitorial services
▶ Storekeeping, accounting etc.
▶ Breakdown Maintenance ( Corrective
▶ Preventive maintenance(PM)
▶ Lubrication & Inspection
▶ Predictive maintenance ( Condition
▶ Is a form of PM
▶ by tracing the performance of the
machine over its operating life,
deterioration that can occur at various
intervals of time is predicted. Early
symptoms of failure are identified and
proper maintenance measures
▶ Is repairing of the machine at planned intervals so that sudden
breakdowns could be prevented and costly downtime avoided.
This work is generally done when the shop can spare the
machine for repairs, generally during off shift hours, Sundays
▶ Lubrication and Inspection are two constituents of PM
Advantages of PM
▶ Greater safety to workers
▶ Reduction in production down time
▶ Lesser expenditure on repairs due to fewer repetitive and large scale repairs
▶ Less spare parts
▶ Prolongs the life of the machine
▶ Maintains quality and continuity of production
Disadvantages of PM
▶ High control on records and analysis, planning & scheduling
▶ Monitoring of parameters like temperature, lubrication, noise, corrosion
,leaks etc are high. The equipments to do that also are costly.
▶ Optimum PM is required, hence correct judgement is needed. Too much or
too little is not good.