RAMCO INSTITUTE OF TECHNOLOGY
Assistant Professor (Senior Grade)
Department of Mechanical Engineering
MAINTENANCE POLICIES –
Maintenance categories – Comparative merits of
each category – Preventive maintenance,
maintenance schedules, repair cycle - Principles
and methods of lubrication – TPM.
Breakdown / Reactive Maintenance
• The equipment is allowed to operate till no
failure occurs. No maintenance work is
carried out in advance to prevent the failure.
• The people wait till equipment fails and
• Its ineffective and extremely expensive.
• Poor planning and incomplete repair will be
contributed for high maintenance cost.
Limitations of Reactive Maintenance
• Most repairs are poorly planned due to time
constraint caused by production and plant
• This approach focus only on repair or the
symptoms of failure and not on the root
cause of failure.
• Corrective Maintenance:
Its focused on regular planned tasks that will
maintain all critical machinery and system
in optimum operating conditions.
1. Eliminate breakdowns
2. Eliminate deviations from optimum
3. Eliminate unnecessary repairs
4. Optimize all critical plant systems.
• Corrective maintenance can be defined as
a maintenance task performed to identify,
isolate, and rectify a fault so that the failed
equipment, machine, or asset can be
restored to an operational condition within
• Corrective maintenance is maintenance
which is carried out after failure detection
and is aimed at restoring an asset to a
condition in which it can perform its
• It is the maintenance program which is
committed to the elimination or prevention of
corrective and break down maintenance.
• It involves periodical evaluation of critical
equipment, machinery to detect problem and
schedule maintenance task to avoid
degradation in operating conditions.
• Its designed for day to day maintenance like
cleaning, inspection, lubricating, retightening
etc., to retain the healthy condition of
Benefits of Preventive Maintenance
• It maintains the equipment in good
condition to preventing them from bigger
• Prolongs the effective life of the equipment.
• Detect the problem at earlier stages.
• Minimize / eliminates the rework.
• Reduces unplanned downtime.
• It is a management technique that uses
regular evaluation of the actual operating
conditions of plant equipment, production
systems and total plant operation.
• Predictive maintenance as regard to
maintenance management, based on need,
will provide necessary data for scheduling
of preventive and corrective maintenance
• Predictive maintenance (PdM) techniques are
designed to help determine the condition of in-
service equipment in order to predict when
maintenance should be performed. This approach
promises cost savings over routine or time-based
preventive maintenance, because tasks are
performed only when warranted.
Its helps to improve/increase,
• The production capacity
• Product quality
• Overall effectiveness of production function.
Benefits of predictive Maintenance:
• Reduced breakdown losses
• Reduction of Quality defects
• Increased net operating profit
• Reduced maintenance cost
Condition Based Maintenance
• Condition-based maintenance (CBM),
shortly described, is maintenance when
need arises. This maintenance is performed
after one or more indicators show that
equipment is going to fail or that equipment
performance is deteriorating.
Condition Based Maintenance Techniques
• Vibration Monitoring:
Determines the actual condition of
equipment/machines by studying the noise or
vibration produced during functioning.
Determines the condition of plant machinery,
system etc. by studying the emission of infra
red energy ( Temperature)
Determines the dynamic condition of bearing
lubrication, rotor support structure of
machinery etc. by adopting any one of the
techniques like lubricating oil analysis and
wear particle analysis.
• Electrical motor Analysis
Determines the problem within motors and
• Visual inspection:
Determines the conditions of working
elements visually based on the experience.
Reliability Centered Maintenance (RCM)
• RCM is one of the well established
systematic and a step by step instructional
tool for selecting applicable and appropriate
maintenance operation types.
• It helps in how to analyze all failure modes
in a system and define how to prevent or
find those failures early.
The rough process of RCM is as follows:
• Target products or systems of maintenance
should be clearly identified, and necessary
data should be collected.
• All possible failures and their effect on
target products or systems are
Applications of RCM
• When designing, selecting and installing
new systems in a plant
• When setting up preventive maintenance for
complex equipment and systems for which
are not clear on how they work.
Total Productive Maintenance (TPM)
• In industry, total productive maintenance
(TPM) is a system of maintaining and
improving the integrity of production and
quality systems through the machines,
equipment, processes, and employees that
add business value to an organization.
• It’s a maintenance program which involves a
newly defined concept of maintaining plants
• To increase the production, at the same time
increasing employee morale and job
• To maximize plant and equipment
effectiveness to achieve optimum life cycle
cost of equipment.
Goal of TPM
Evolution of TPM
• Dr.W.Edward Deming – Japanese Industry
• Nippon Denso of Toyoto groups – Quality
circle, Involving employees participation
Implementation of TPM
Introduction on TPM
(Take off phase)
Stage I Initialization
• Discussions with workers union
• Establish basic TPM policies and goals –
Analyze the existing condition
• Preparation and formulation of master plan
Stage II Introduction on TPM
(Take off phase)
• Formal presentation by top executive with
all employees attending.
• To get the full support of all employees.
• Also invite our external customers,
suppliers, contractors and affiliated
companies to get their supports.
Stage III Implementation
• 5’S Principle
• Autonomous Maintenance (JISHU HOZEN)
• Planned Maintenance
• Quality Maintenance
• Office TPM
• Safety, Health and Environment
Stage IV Institutionalization
• Once TPM has been implemented, it should
be properly monitored and evaluated and
some reward system can be introduced for
• The Japanese institute for productive
maintenance runs an annual PM Excellence
Benefits of TPM
• Enhanced/ improved productivity and
• Reduction of manufacturing cost.
• Customer satisfaction by delivering right
quantity at right time with expected quality.
• Minimization of accidents.
• High confidence level among employees.
Category TQM TPM
Objective To have quality
To have reliable
Means of achieving Through
Target Minimized defective
Major losses in an organization
• Equipment efficiency based losses
1. Failure/Breakdown losses
2. Setup/adjustment losses
3. Minor stoppage/ idling loss
4. Speed loss-Operating at low speeds
5. Defect/Rework loss
6. Scheduled downtime loss
• Human work efficiency based losses
1. Management loss
2. Operating motion loss
3. Line organization loss
4. Measurement and Adjustment loss
• Effective use of Production Resources
1. Energy loss
2. Die, Jig and Tool breakage loss
3. Yield loss
Pillar -5: Quality Maintenance(QM)
1. Its aimed towards customer delight by
getting them the highest quality through
defect free manufacturing.
2. Its focused on eliminating non
conformances in a systematic manner.
3. Understanding of what parts of the
equipment affect product quality and begin
to move potential quality
Pillar -6: Training
Its aimed to have multi skilled employees
whose morale is high and who are eager to
work and perform all the required
functions independently and effectively.
Its not sufficient to know only “Know-How”
but they should also learn “Know-Why”.
Achieve and sustain downtime at zero on
Achieve and sustain zero losses due to lack
Aim for 100% participation in suggestion
Pillar -7: Office TPM
• To improve productivity, efficiency in the
administrative functions and identify-
• Analyzing processes and procedures
towards increased office automation.
Office TPM Major Losses
• Processing loss.
• Cost loss (Accounts, Marketing, Sales)
• Communication loss
• Idle loss
• Set-up loss
• Accuracy loss
• Office equipment breakdown
• Communication channel breakdown(Telephone,
• Non availability of correct on line stock status
• Customer complaints due to logistics
Benefits of Office TPM
• Involvement of all people in support functions for
focusing on better plant performance.
• Better utilized work area
• Reduce repetitive work
• Reduced inventory levels in all parts of the supply
• Reduced administrative cost
• Reduction in number of files
• Reduced manpower
• Clean and pleasant work environment
• Maintenance scheduling is a joint maintenance
operations activity in which maintenance agrees to
make the resources available at a specific time
when the unit can also be made available by
He/She should ensure that the work is properly
planned with respect to customer requirements,
Stores material, directly purchased materials, etc.
also work to be carried out with line of safety
requirements should be described.
He/She should ensure that,
• Trades are available to conduct the work
during the schedule duration.
• Materials and service availability.
• Communicating the details of the above to
person involved in maintenance and
3. Maintenance Supervisor
He/She will be responsible for the day to day
activities comprised in weekly schedule and
also determine the business availability.
He/She execute the assigned task and keep
informing the maintenance team, the outcome
as well as any practical difficulty in their part,
for any further analysis.
5. Storeroom personnel:
They maintain the records of receipt of goods
and notify if any damage exists.
6. Operation Superintendent:
He must be kept informed in advance about
the equipment condition.
He is the person responsible for securing the
equipment and report back to maintenance
personnel if any deviation is observed.
• To reduce wear and heat between contacting
surfaces in relative motion.
• Coefficient of friction could be reduced and inturn
heat and wear of the surfaces.
• Lubrication also aids to
1. Reduce oxidation and rust formation
2. Transmit mechanical power in hydro fluid
3. Seal against dust, dirt and water.
• Any materials used to reduce friction between
wearing surfaces with high coefficient of
friction, by establishing low viscous film are
Methods of Lubrication:
• Hydrostatic Lubrication
• Hydrodynamic/ Fluid film Lubrication
• Boundary Lubrication
• Elasto hydrodynamic Lubrication (EHD)
• Extreme pressure Lubrication (EPL)
Method of lubrication is based on:
Mean fluid film thickness
R is less than or equal to 1 for Boundary/Hydrostatic
R is in between 5 and less than or equal to 100 for
mixed lubrication or EHD/EPL
R is between 1 and 5 for fluid film lubrication
1. Hydrostatic Lubrication
A thin film of lubrication is created between
the journal and the bearing by supplying
lubricant under pressure with an external
source like pump.
2. Hydrodynamic/ Fluid film Lubrication
In heavy loaded bearing such a thrust
bearings and horizontal journal bearings
apart from viscosity of fluid, higher fluid
pressure is also required to support the
In hydrodynamic lubrication a fluid wedge is
formed by the relative surface motion of the
journals over their bearing surfaces.
3. Boundary Lubrication
When a full fluid film is not developed
between rubbing surfaces, the thickness of
film may be reduced so that dry contact is
formed at high points of mating surfaces.
Ex: Gear Teeth
4. Elasto hydrodynamic Lubrication (EHD)
• The lubrication principle is applicable to
rolling bodies such as ball or roller bearings.
• Elastic deformation of the contacting bodies
under load and hydrodynamic effects
forcing the lubricant to separate the
contacting surfaces while the pressure of
the load is deforming them.
• Ex: Ball bearings
5. Extreme pressure Lubrication (EPL)
In heavy loading applications, oil temperature
raises beyond the anti wear protection.
Under this situation lubricants containing
additives that protect against extreme
pressure (EP) lubricants are used.
EPL can be achieved by chemical compounds
of boron, phosphorus, sulphur, chloride or
combination of these.