Maintenance is required to ensure equipment continuously performs its intended function. There are two main categories of maintenance - machine/equipment maintenance and building maintenance. The goals of maintenance are to keep production systems functioning with minimal costs and avoid disruptions. Over time, maintenance philosophies have evolved from breakdown-based to more proactive approaches like preventive maintenance, predictive maintenance, and total productive maintenance. Considering life cycle costs is important for accurately assessing the cost effectiveness of assets from acquisition through operation and maintenance to disposal.

1. Unit 1
MAINTENANCE

2. Maintenance
• Maintenance is the activity carried out on an
asset in order to ensure that the asset
continuously perform its intended function.
• Or to repair an equipment that has failed, or to
keep the equipment running , or to restore to
its favorable operating condition.
• It improves system’s overall reliability,
availability, and consequently higher
production efficiency.

3. Two Basic categories
• Machine & equipment maintenance
• Building maintenance

4. Goal of Maintenance
• To keep production systems in good working order
at minimal cost
• Reasons for maintenance
• To avoid production or service disruptions
• To avoid missed delivery dates
• To keep resource in good working condition
• To maximize useful life of equipment
• To minimize operating cost
• To minimize breakdowns
• To enhance safety of manpower

5. Benefits of Maintenance
• Increased safety
• Reduce downtime
• Trouble free service and output at rated
capacity
• Reduced cost of operations
• Real time product delivery

6. Evolution of maintenance
philosophy
• First generation(1930-40): fix it when broke
(Breakdown maintenance)
• Second generation (1950-70): scheduled
overhauls (Preventive maintenance)
• Third generation -after1980- condition
based, failure data analysis, reliability
centered maintenance, Total Productive
Maintenance

7. How Machines/equipment fails?
• There is a definite pattern of life span of a
machine/equipment
1. Infant mortality: due to presence of weak or
substandard components, design inadequacy,
2. Second stage –more useful ,less failure if there
then they are unpredictable
3. Might fail: reasons are abrupt changes in stress
distribution in the components, fatigue due to
flaws in the molecular structure of the metals
or plastics involved, sheer quality deficiency

8. Maintenance cost
• Breakdown of machine makes the workers and
machine idle resulting in loss of production, delay in
schedules and expensive emergency repairs.
• Down time (idle time)
• Cost of spares
• Cost of maintenance labor
• Losses due to inefficient operation of machine
• Capital requirements required for replacement

9. Maintenance policy
• Reactive maintenance
• Proactive maintenance
• Predictive maintenance
• Total Productive Maintenance

10. Reactive vs Proactive
Reactive Maintenance:
• Breakdown maintenance
• Reactive approach; dealing with breakdowns or
problems when they occur
Proactive Maintenance:
• Preventive maintenance
• Proactive approach; reducing breakdowns
through a program of lubrication, adjustment,
cleaning, inspection, and replacement of worn
parts

11. Breakdown maintenance
• It is emergency based policy in which plant
operates until it fails.
• The maintenance staff locate any
mechanical, electrical and any other fault to
correct it immediately

12. Preventive maintenance
• It prevents the probable breakdown and it
ensures smooth and uninterrupted
production by anticipating breakdowns and
taking corrective actions
• Preventive maintenance policy has four
forms
(1) Time based (2) Work based (3)
Opportunity based (4) Condition based

13. Two aspects of preventive
maintenance
• Inspection
• Servicing

14. Preventive V/S Breakdown
Maintenance
• PM is a routine inspection designed to
detect potential failure condition and make
minor adjustments and repairs that will help
prevent major operating problem
• BM is the emergency repair and it involves
higher cost of facilities and equipment that
have been used until they fail to operate

15. Continue……
• An effective PM requires properly trained
personnel, regular inspection and have to
maintain regular records
• PM is planned in such a way that it will not
disturb the normal operation
• BM stops normal activities and the machine
and the operators are rendered idle till
equipment is brought back to normal
condition of working

16. 15S-16
Total Maintenance Cost
Breakdown and
repair cost
Optimum Amount of
preventive maintenance
Cost
Total Cost
Preventive
maintenance cost
Table 15S.1

17. Total Productive Maintenance
• Now a days manufacturing has become
automated and in such situation quality
depends on reliability of equipment
• Though operation have been automated,
maintenance still depends on human input
• TPM is a company wide equipment
maintenance system that organizes all
employees from top management to production
line worker and can support highly
sophisticated and advance equipment.

18. TPM continue……
• TPM has two objectives
• Zero Breakdowns
• Zero Defects
• When breakdown and defects are eliminated
the equipment utilization will improve

19. • “TPM is defined as productive maintenance
involving total participation.”
• The word total in TPM refers to
• Total effectiveness
• Total maintenance including maintenance
prevention and corrective maintenance
• Total participation of employees

20. TPM tries to eliminate three big losses that
are obstacles to equipment effectiveness:
(1)Downtime: equipment failure from
breakdown and set up & adjustment
(2)Speed losses: minor stoppages, reduced
speed
(3)Defect: process defects (due to scrap),
reduced yields

21. TPM development program
• Basically there are 3 stages and 12 steps of
TPM development program
• Preparation stage: a suitable environment
is created by establishing a plan for
introduction
• Preliminary Implementation stage: here
goals are set and also a time frame is
mapped in order to boost the morale of
employee
• Implementation stage: company measures
the actual result achieved against TPM
targets

22. Predictive Maintenance
• Predictive maintenance
• An attempt to determine when best to perform
preventive maintenance activities

23. Maintenance performance
• Productivity of Maintenance=
Output/Maintenance cost
• Downtime index= downtime
hoursX100/Production hours
• Maintenance cost index= maintenance
costX100/Capital cost

24. Life Cycle Costing

25. • Cost effectiveness of a system can be
simply defined as the measure of a system
in terms of mission fulfillment (system
effectiveness) and total life cycle costs'.
• Cost effectiveness, (which is similar to the
standard cost benefit analysis in industrial
and business parlance) can be expressed in
various terms, depending upon the specific
mission or system parameters, that one
wishes to measure.
• Thus, Cost Effectiveness figure of Merit=
System Effectiveness / Life Cycle Cost
(LCC)

26. • It therefore flows out that, while evaluating
any equipment, life cycle costs have to be
considered to arrive at the cost
effectiveness, else we will be evaluating the
equipment only on 'System Effectiveness'
parameter.

27. Life Cycle- Womb to tomb approach
• Any equipment which is in use in the armed
forces, had been introduced at a particular
time after the need had been felt, operated
and used by the concerned agencies and
discarded when it no more fulfilled the
mission assigned to it.
• This in effect is the Life Cycle Concept of
an equipment and can be defined as the
period since an equipment is conceived,
developed, produced or procured, operated
and maintained and finally discarded.

28. Phases of Life Cycle.
• Need or Requirement Phase. In this phase, based on the threat
perception, operational plans, technological development necessities, the
need for a particular equipment is established. After the feasibility study,
the equipment is undertaken by R&D wing for development.
• “ Design and Development Phase. In this phase, R&D wing designs the
equipment as per the norms laid down. After the prototypes have been
developed, technical trials are conducted.
• “ Evaluation and Trials. After the technical trials, the equipment is
subjected to extensive user and environmental trials to validate the
performance In case of imported equipment, study teams may visit foreign
countries to identify and evaluate an equipment before it is imported for
trials.

29. • “ Manufacture or Procurement After the decision to
introduce an equipment is taken, it is either manufactured
or procured from trusted vendors.
• “ Operation and Maintenance. Equipment is issued to
units for training, equipping and usage. It is operated and
maintained. Periodic repairs and overhauls are carried out
and modification and modernisation programmes are
implemented as applicable.
• “ Disposal. Once the equipment has outlived its
physical/ operational/economic life, or has technologically
become obsolete, it is discarded and disposed off.

30. Economic life of an Equipment
• Useful economic life of an equipment can be defined as the
period for which the equipment fulfils its mission as per the
laid down qualitative requirements at the desired
costs. Besides the physical life, this period is affected by
operational, economic, environmental and other
conditions. Factors affecting the useful economic life of an
equipment are as under:
• “ Operational Obsolescence. The equipment must fulfil
the task in the contemporary operational environment
Operational obsolescence will set in, due to its non-
effectiveness in the present operational scenario. This will
curtail the fife of equipment.
• “ Technological Obsolescence. In the present environment
of rapid technological advancement, equipment may become
technologically obsolescent and lose its effectiveness thus
curtailing its life.

31. • “ Economic Factor. Operation and maintenance of the
equipment must remain within the Emits of cost
effectiveness. If the cost of operation and maintenance
becomes very heavy, the equipment may be phased out earlier
thus reducing its life.
• “ Obsolescence of Support System. If the support
requirements like spares needed for functioning of equipment
are not available, the equipment ceases to function and is
hence discarded.
• “ Stretch Potential. Life of equipment can be enhanced by
way of modifications and modernisation to maintain its
reliability and functioning at the desired level. Greater the
amenability to modernisation and modification greater the
stretch potential and longer is the life of the equipment

32. Assessment of Life of an Equipment
• It is of utmost importance that life of equipment be
accurately assessed by scientific methods.
• This is to avoid gaps in planning and to forecast the
replacements, modernisation and formulate realistic
acquisition policies.
• In the past, when equipment and weapons systems were
not as sophisticated and complex as they are today, life of
equipment was assessed mainly by past performances in
an empirical manner. This was not a reliable
method. However, with introduction of the state-of-the-
art equipment various tests have been - evolved to assess
the Time between Overhauls (TBO) and total useful life
more realistically- various methods for predicting life of
equipment are in vogue today. Some of the important
ones are:

33. • Technological Forecasting. At the time of
introduction, it is necessary that anticipated
technological advancement and future
operational environment be predicted.
• Accelerated Life Testing. The present day
technology has made it Possible to test the
equipment scientifically and predict the
life. For example, by firing limited number
of shells from a gun and measuring the wear
and tear, scientific estimate of the life of the
barrel is made. Even if the absolute cost is
high, the overall savings could be
phenomenal.

34. • Destructive Trials. The equipment is operated till it ceases to
function. Though this is a costly method, it not only helps in
assessment of in service life period but also in evaluation of its
maintenance, repairs and overhauls requirements.
• Fatigue Life Testing. This method of testing is used extensively
for components that are subjected to continuous vibrations or
undergo continuous reversal of stresses like main rotor blades of a
helicopter. Components are subjected to this test for a specific
duration after which computerised analysis of inter-crystalline
molecular structure is made to determine the TBO and useful life.
• Calendar Life Testing. The life of some components is limited to
a calendar life instead of the actual usage in turns of Kms or
hours. Usually such components are rubber parts or other similar
items that deteriorate with age or environmental conditions like
humidity, temperature, salinity etc. Methods like Simulated
Environment Chamber tests are used to determine life of such
components.

35. LCC
• Cost Breakdown Structure
• Description of all the categories.

36. Life Cycle Costing
• Packing charges.
• Insurance charges.
• Exchange rates.
• Payment schedule - payment and delivery -
penalties and interests.
• Any advance payments.
• Credit facilities.
• Transportation charges.