The combination of all technical and administrative actions, including supervision actions,

intended to retain an item in, or restore it to, a state in which it can perform a required function.
Maintenance is a set of organised activities that are carried out in order to keep an item in its best
operational condition with minimum cost acquired.
Problems associated
 Lack of management attention to maintenance.
 Little participation by accounting in analyzing
and reporting costs.
 Difficulties in obtaining time and cost
estimates for maintenance work.
 Difficulties in measuring performance.

economic aspects of maintenance

Maintenance does not directly earn profit. It is represented as an element of cost on the
accounting records of a company. The only way it can contribute to the profitability of a
company is by reduction of the total costs.
Elements of cost influenced my maintenance
1. Downtime cost:
It is made up ofa. Loss of profit for the period that the machine remains
stopped for attention by maintenance.
b. Wages paid to the direct workers while they remain
idle.
c. Depreciation of the machine for the same period of
time.
d. Overheads proportioned for the period of machine
idleness as per the company policy.
e. Loss due to scrapping or reworking of material that
may be spoiled due to maintenance stoppage.
2. Cost of spares and other materials used for repairs.
3. Cost of maintenance labor and overheads of the
maintenance department.
4. Losses due to inefficient operations of the machines.
These losses arise because machines can either not turn
out the requisite quantity or its condition creates
problems relating to quality of products.
5. Capital expenditure required for replacement of
machines.

. Inspection or checkups
• Inspection is an essential function of the maintenance
programme. Crews (stuff) kept for this purpose should be well
trained. These crews carry out both external and internal
inspection.
• External inspection means to watch for and detects from a)
Unusual sound/ vibration b) Unusual heat/ smoke etc. when
machine is in operation.
• Internal inspection means inspection of internal parts such as
gears, bearings etc.
• Frequency of inspection should be decided very carefully, as
too less inspection may cause breakdowns, as defects could
not be traced out and rectified immediately; while too much
inspection means wastage of machine time and labor
productivity.
• For the purpose of inspection, machine can be categorized as:
1. Important Machine: Those machine which can disturb whole
of the production, are delicate and require much time to repair.
More attention should be given for inspection of these
machines and schedule for inspection, cleaning, lubrication
should be followed rigidly.
2. Ordinary Machine: Frequency of inspection can be kept as
low as they do not affect the production.
2. Lubrications
• Mechanical components like gears, bearings and other
frictional surfaces give good performance for long periods,
when they are systematically lubricated.
• Systematic lubrication means the application of right type of
lubricant at the right time, at right place and in right quantity.
• For lubrication, a lubrication schedule should be prepared and
that should be followed strictly.
3. Planning and Scheduling
• Every preventive maintenance work should be pre-planned in
detail on the basis of the analysis done on the past records.
• A scheduled program thus prepared should be followed
strictly.
• Program should be in detail specifying the point requiring
daily, weekly. Monthly, half yearly or yearly attention.

4. Records and Analysis

• Good record keeping is essential for good maintenance, as it
helps in forecasting maintenance. For this purpose following
records are generally maintained-
Operation Manual
Maintenance instruction manual
History cards and history registers
Spares procurement register
Inspection register
Log books
Defects register
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4. Records and Analysis….
• These records helps the plant engineers and General Manger
to take decisions. The analysis made on the basis of these
records help in-
Preventing defects rather than rectifying after breakdowns.
Knowing the machine reliability and thus helps in
production planning.
Deciding life of machine.
Forecasting defects and planning to rectify them before
the failure occurs.
Frequency of inspection and check-ups.
Deciding for the purchase of a machine.
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5. Training of Maintenance Personnel
• For the success of maintenance, a sound training is essential
for the maintenance personnel.
• Hence the technicians and supervisors are trained to carry out
maintenance, inspection and repairs in a systematic way.
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6. Storage of spare parts
• Sometimes machine remain idle for want of spare parts for
considerable time and thus it affects considerable loss of
production.
• Hence it is essential to keep the spare parts so as to avoid loss
of production.
• But the judgment and experience of high order is required for
deciding the number of such parts. As storage of a large
number of parts will mean blocking of capital.
Requirements for good maintenance

For achieving maintenance of high order, following are some of the

essential requirements-
Good supervision and administration of maintenance department.
Proper control of work.
Correct, clear and detailed instructions be given to the maintenance
crew and to the operators.
Well training is essential.
A good lubrication program should be chalked out.
Proper maintenance record should be maintained.
Adequate stock of spares should always be kept.
Surroundings should be dust free and clean with proper ventilation
and illumination.
Manufacturers of the machine tools should be consulted as and
when required.
Maintenance department should remain in contact with planning
and purchasing department in deciding the types of machine tools
to be purchased.
Reactive Maintenance • Reactive maintenance is basically the “run it till it breaks” maintenance mode.
No actions or efforts are taken to maintain the equipment as the designer originally intended to ensure
design life is reached.

the average maintenance programs follows:

• >55% Reactive

• 31% Preventive

• 12% Predictive

• 2% Other.

Advantages
• Low cost.
• Less staff.
Disadvantages
• Increased cost due to unplanned downtime of equipment.
• Increased labor cost, especially if overtime is needed.
• Cost involved with repair or replacement of equipment.
• Possible secondary equipment or process damage from
equipment failure.
• Inefficient use of staff resources.

Preventive maintenance can be defined as

follows:
• Actions performed on a time- or machine-runbased schedule that detect, preclude, or
mitigate degradation of a component or system with the aim of sustaining or extending
its useful life through controlling degradation to an acceptable level.
Advantages
• Cost effective in many capital-intensive processes.
• Flexibility allows for the adjustment of maintenance periodicity.
• Increased component life cycle.
• Energy savings.
• Reduced equipment or process failure.
• Estimated 12% to 18% cost savings over reactive maintenance
program.
Disadvantages
• Catastrophic failures still likely to occur.
• Labor intensive.
• Includes performance of unneeded maintenance.
• Potential for incidental damage to components in conducting
unneeded maintenance.

Predictive maintenance

Measurements that detect the onset of a degradation mechanism, thereby allowing casual stressors to
be eliminated or controlled prior to any significant deterioration in the component physical state.
Results indicate current and future functional capability.

Predictive Maintenance
Advantages
• Increased component operational life/availability.
• Allows for preventive corrective actions.
• Decrease in equipment or process downtime.
• Decrease in costs for parts and labor.
• Better product quality.
• Improved worker and environmental safety.
• Improved worker moral.
• Energy savings.
• Estimated 8% to 12% cost savings.
Disadvantages
• Increased investment in diagnostic equipment.
• Increased investment in staff training.
• Savings potential not readily seen by management

Reliability Centered Maintenance

a process used to determine the maintenance requirements of any physical asset in its operating
context.”

How to Initiate Reliability Centered

Maintenance
The road from a purely reactive program to a RCM program is not an easy one.
The following is a list of some basic steps that will help to get moving down this
path.
1. Develop a Master equipment list identifying the equipment in your facility.
2. Prioritize the listed components based on importance to process.
3. Assign components into logical groupings.
4. Determine the type and number of maintenance activities required and
periodicity using:
a. Manufacturer technical manuals
b. Machinery history
c. Root cause analysis findings - Why did it fail?
d. Good engineering judgment
5. Assess the size of maintenance staff.
6. Identify tasks that may be performed by operations maintenance personnel.
7. Analyze equipment failure modes and effects.
8. Identify effective maintenance tasks or mitigation strategies.
Bath Tub Curve

• Infant / Green / Debugging / Burn-in-period:

Many components fail very soon after they are
put into service. Failures within this period are
caused by defects and poor design that cause an
item to be legitimately bad. These are called
infant mortality failures and the failure rate in this
period is relatively high. Good system vendors
will perform an operation called "burn in" where
they put together and test a system for several
days to try to weed out these types of problems
so the customer doesn't see them.
• Chance failure / Normal Operating Life: If a
component does not fail within its infancy, it
will generally tend to remain trouble-free over
its operating lifetime. The failure rate during
this period is typically quite low. This phase, in
which the failure rate is constant, typically
represents the useful life of the product.
• Wear out / Ageing: After a component reaches
a certain age, it enters the period where it
begins to wear out, and failures start to
increase. The period where failures start to
increase is called the wear out phase of
component life.
Stage Description Characteristics Mitigation
Many components fail very soon
after they are put into service. Good system vendors will
Infant / Failures within this period are perform an operation called
Green / caused by defects and poor design "burn in" where they put
Debugging / that cause an item to be together and test a system for
Burn-in legitimately bad. These are called several days to try to weed out
Period infant mortality failures and the these types of problems so the
failure rate in this period is customer doesn't see them.
relatively high.
The failure rate during this
Chance
If a component does not fail within period is typically quite low.
failure /
its infancy, it will generally tend to This phase, in which the failure
Normal
remain trouble-free over its rate is constant, typically
Operating
operating lifetime. represents the useful life of the
Life
product.
Wear out / After a component reaches a The period where failures start to
Ageing certain age, it enters the period increase is called the wear out
where it begins to wear out, and phase of component life.
 Stage Description Characteristics Mitigation
failures start to increase.

TPM is a maintenance management system for

optimizing the productivity of manufacturing
equipment through systematic equipment
maintenance involving employees at all levels.
• It is a maintenance program which involves a newly
defined concept for maintaining plants and equipment.
The goal of the TPM is to markedly increase
production, while at the same time, increasing
employees’ morale and job satisfaction.
• In TPM, everyone is involved in keeping the equipment
in good working order to minimize production losses
from equipment repairs, set ups etc.

TPM eliminates six big losses which are as listed below

1. Breakdowns which can result in long, expensive
repairs.
2. Set ups and change overs which can take much longer
time than needed.
3. Idling and minor stoppages which are hard to quantify
and add up to losses.
4. Reduced equipment speed which results in gradual
deterioration of equipment cycle times.
5. Defects and reworks which results in quality losses
and unhappy customers.
6. Start-up losses which can take much time to get to
steady state after a change.

Benefits of TPM
• Increased equipment productivity.
• Reduced equipment downtime.
• Increased plant capacity.
• Lower maintenance and production cost.
• Approaching zero equipment-caused defects.
• Improved return on investment.
• Rectified customer complaints.
• Reduced accidents.
• Ensuring pollution control measures.
• Better Understanding of the performance of equipment.
• Better understanding of critical equipment and the worth of deploying
improvement effort for potential benefits.
• Improved teamwork and a less adversarial approach between production
and maintenance.
• Improved procedures for changeovers and set ups, better training of the
operators and maintainers, which all lead to reduced costs and better
service.
• Generaly increased involvement of the work force.

Equipment maintenance techniques

• TPM uses four equipment maintenance techniques
1. Preventive maintenance: Involves cleaning, inspection,
oiling and re-tightening of the parts which help to retain
the healthy condition of the equipment and prevents
failures through the prevention of deterioration, periodic
inspection or condition diagnosis to measure data about
deterioration.
Preventive maintenance is further classified into Periodic
maintenance (Time based maintenance, TBM) and
predictive maintenance.
• Time based maintenance consists of periodically
inspecting, servicing and cleaning equipment and
replacing parts to prevent failure and process
problems.
• The predictive maintenance is condition based
maintenance which manages trend values by
measuring and analyzing data about
deterioration and employs surveillance system
which is designed to monitor conditions through
an on-line system.
2. Corrective Maintenance: It is to modify or
improve an equipment for increased reliability and
easier maintenance. This means that the
equipment with design weaknesses are redesigned
to improve reliability or maintainability.
3. Maintenance Prevention: It is to design and
install new equipment that are maintenance-free
based on the study of the weaknesses of the
current equipment.
4. Breakdown Maintenance: It is to repair
equipment quickly after they breakdown.
The 8 Pillars of Total Productive Maintenance (TPM)
Pillar Description

Focuses on designing and installing equipment to ensure it operates

Early Equipment
reliably. Input from operators and maintainers helps reduce future
Maintenance
failures and ease maintenance activities.

Jishu Hozen Empowers operators to take ownership of their equipment by

(Autonomous performing regular checks, cleaning, and basic maintenance, ensuring
Maintenance) the equipment runs smoothly.

Kaizen (Continuous Encourages small, incremental changes to processes and equipment to

Improvement) improve productivity, efficiency, and eliminate waste.

Establishes a schedule for regular maintenance activities based on

Planned Maintenance
equipment usage and condition, minimizing unexpected breakdowns.

Focuses on preventing defects and ensuring equipment operates

Quality Maintenance consistently to produce high-quality products. Involves measures like
root cause analysis and standardization.

Equips operators and maintenance personnel with the skills and

Training knowledge needed to handle equipment effectively and contribute to
TPM initiatives.

Applies TPM principles to administrative and office processes to

Office TPM
improve efficiency and eliminate bottlenecks in support functions.

Safety, Health, and Ensures the workplace is safe, environmentally friendly, and
Environment conducive to employees’ well-being, reducing accidents and hazards.
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