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ME6012 MAINTENANCE ENGINEERING L T P C 3 0 0 3
OBJECTIVES:
To enable the student to understand the principles, functions and practices adapted
in industry for the successful management of maintenance activities.
UNIT I PRINCIPLES AND PRACTICES OF MAINTENANCE PLANNING 9
Basic Principles of maintenance planning – Objectives and principles of planned
maintenance activity – Importance and benefits of sound Maintenance systems –
Reliability and machine availability – MTBF, MTTR and MWT – Factors of availability
–Maintenance organization – Maintenance economics.
UNIT II MAINTENANCE POLICIES – PREVENTIVE MAINTENANCE 9
Maintenance categories – Comparative merits of each category – Preventive
maintenance, maintenance schedules, repair cycle - Principles and methods of lubrication
– TPM.
UNIT III CONDITION MONITORING 9
Condition Monitoring – Cost comparison with and without CM – On-load testing and
offload testing – Methods and instruments for CM – Temperature sensitive tapes – Pistol
thermometers – wear-debris analysis
UNIT IV REPAIR METHODS FOR BASIC MACHINE ELEMENTS 10
Repair methods for beds, slide ways, spindles, gears, lead screws and bearings – Failure
analysis – Failures and their development – Logical fault location methods – Sequential
fault location.
UNIT V REPAIR METHODS FOR MATERIAL HANDLING EQUIPMENT 8
Repair methods for Material handling equipment - Equipment records –Job order systems
-Use of computers in maintenance.
TOTAL: 45 PERIODS
TEXT BOOKS:
1. Srivastava S.K., “Industrial Maintenance Management”, S. Chand and Co., 1981
2. Venkataraman .K “Maintancence Engineering and Management”, PHI Learning, Pvt.
Ltd.,2007
REFERENCES:
1. Bhattacharya S.N., “Installation, Servicing and Maintenance”, S. Chand and Co., 1995
2. White E.N., “Maintenance Planning”, I Documentation, Gower Press, 1979.
3. Garg M.R., “Industrial Maintenance”, S. Chand & Co., 1986.
4. Higgins L.R., “Maintenance Engineering Hand book”, 5th Edition, McGraw Hill,
1988.
5. Armstrong, “Condition Monitoring”, BSIRSA, 1988.
6. Davies, “Handbook of Condition Monitoring”, Chapman & Hall, 1996.
7. “Advances in Plant Engineering and Management”, Seminar Proceedings - IIPE, 1996.

3
TABLE OF CONTENTS
S.NO TOPIC P.NO
1 Aim and objective of the subject 4
2 Detailed Lesson Plan 5
Unit-I-PRINCIPLES AND PRACTICES OF MAINTENANCE PLANNING
3 Part - A (2marks Q &A) 7
4 Part - B (16marks Q &A) 8
Unit-II-MAINTENANCE POLICIES – PREVENTIVE MAINTENANCE
Unit-III-CONDITION MONITORING
Unit-IV-REPAIR METHODS FOR BASIC MACHINE ELEMENTS
Unit-V-REPAIR METHODS FOR MATERIAL HANDLING EQUIPMENT
ANNA UNIVERSITY PREVIOUS YEAR QUESTION PAPER
13 UQ-APRIL/MAY 2017 84
14 UQ-NOV/DEC 2016 86
15 UQ-APRIL 2016 88
16 UQ-NOV/DEC 2015 90
17 UQ-APRIL/MAY 2015 92
18 UQ-NOV/DEC 2014 94
19 UQ-APRIL 2014 96
20 UQ-NOV/DEC 2013 98
21 UQ-MAY/JUNE 2013 100

4
ME 6012 MAINTENANCE ENGINEERING L T P C 3 0 0 3
1. Aim and objective of the subject:
 To introduce the students to discipline and profession of applying engineering
concept to the optimization of equipment procedure and department budgets to
achieve better maintainability reliability and availability of equipment..
 At the completion of the course, the student should be aware of the industrial
maintenance
2. Need and importance for study of the subject:
 To enable the student to understand the principles, functions and practices adapted
in industry for the successful management of maintenance activities.
 To explain the different maintenance categories like Preventive maintenance
condition monitoring and repair of machine elements.
 To illustrate some of the simple instruments used for condition monitoring in
industry.
3. Industry connectivity:
 The students having knowledge in maintenance engineering can be found
employed in almost all fields of industries.

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DETAILED LESSON PLAN
Name of the Subject : ME 6012- MAINTENANCE ENGINEERING
TEXT BOOKS:
1. Srivastava S.K., “Industrial Maintenance Management”, S. Chand and Co., 1981
2. Venkataraman .K “Maintancence Engineering and Management”, PHI Learning, Pvt.
Ltd.,2007
REFERENCES:
1. Bhattacharya S.N., “Installation, Servicing and Maintenance”, S. Chand and Co., 1995
2. White E.N., “Maintenance Planning”, I Documentation, Gower Press, 1979.
3. Garg M.R., “Industrial Maintenance”, S. Chand & Co., 1986.
4. Higgins L.R., “Maintenance Engineering Hand book”, 5th Edition, McGraw Hill,1988.
5. Armstrong, “Condition Monitoring”, BSIRSA, 1988.
6. Davies, “Handbook of Condition Monitoring”, Chapman & Hall, 1996.
7. “Advances in Plant Engineering and Management”, Seminar Proceedings - IIPE, 1996.
Sl.
No
Unit Topic / Portions to be Covered
Hours
Required
/
Planned
Cumulative
Hours
Books
Referred
PRINCIPLES AND PRACTICES OF MAINTENANCE PLANNING
1
1
Basic Principles of maintenance
planning
1 1 T1,R3
2
Objectives and principles of
planned
maintenance activity
1 2 T1,R3
3
Importance and benefits of sound
Maintenance systems
1 3 T1,R3
4 Reliability and machine availability 1 4 T1,R3
5 MTBF, MTTR and MWT 2 6 T1,R1
6 Factors of availability 1 7 T1,R1
7 Maintenance organization 1 8 T1,R3
8 Maintenance economics 1 9 T1,R1

6
MAINTENANCE POLICIES-PREVENTIVE MAINTENANCE
9
2
Maintenance categories 1 10 T1,R3
10
Comparative merits of each
category
1 11 T1,R1
11
Preventive maintenance,
maintenance schedules, repair cycle
3 14 T1,R3
12
Principles and methods of
lubrication
2 16 T1,R3
13 TPM 2 18 T1,R1
CONDITION MONITORING
14
3
Condition Monitoring 1 19 R1,R3
15
Cost comparison with and without
CM
1 20 R1,R3
16 On-load testing and off load testing 2 22 R1,R3
17
Methods and instruments for CM –
Temperature sensitive tapes
3 25 R1,R3
18 Pistol thermometers 1 26 R1,R3
19 wear-debris analysis 1 27 R1,R3
REPAIR METHODS FOR BASIC MACHINE ELEMENTS
20
4
Repair methods for beds, slide
ways, spindles, gears, lead screws
and bearings
3 30 R1,R3
21
Failure analysis - Failures and their
development
3 33 R1,R3
22 Logical fault location methods 2 35 R1,R3
23 Sequential fault location. 2 37 T1,R3,R1
REPAIR METHODS FOR MATERIAL HANDLING EQUIPMENT
24
5
Repair methods for Material
handling equipment
2 39 T1,R1
25 Equipment records 2 41 T1,R3
26 Job order systems 2 43 T1,R1
27 Use of computers in maintenance. 2 45 T1,R1,R3

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UNIT-I
PRINCIPLES AND PRACTICES OF MAINTENANCE PLANNING
PART – A
1. What are the objectives of Maintenance? (APR/MAY 2014)
The most important objective of the maintenance is the maximization of
availability of equipments and facilities so as to help in achieving the ultimate goals of the
organisation. To achieve minimum breakdown and to keep the plant in good working
condition at the lowest possible cost.
2. Define the term MWT. (APRIL 2016, MAY/JUNE 2012)
Mean Waiting Time for an object in a system is a mathematical term for the
amount of time an object is expected to spend in a system before leaving the system for good.
3. What is the sound Maintenance system? (APRIL 2016)
The profit of any industry depends only on the return of the investment. The
capital cost and operating cost are the major factors involved in any industrial investment. The
life of the equipment and maintenance schedule information provided by manufacturer may
not be realized in practice to make the need for having a sound management system.
4. State the principles of Maintenance planning. (MAY/JUNE 2012)
Plant Management in Maintenance work, Production and Maintenance objectives,
Establishment of work order and recording system, Information based decision making,
Adherence to planned maintenance strategy, Planning of maintenance functions.
5. Define maintenance? (MAY/JUNE2015)
Maintenance is the routine and recurring process of keeping a particular machine or
asset in its normal operating conditions So that it can deliver the expected performance or
service without any loss or damage.
6. Define reliability? (NOV/DEC 2015, MAY/JUNE2014, NOV/DEC 2013, NOV/DEC 2009)
Reliability is defined as the probability that a component/system, when operating
under given condition, will perform its intended functions adequately for a specified period of
time. It refers to the like hood that equipment will not fail during its operation.
7. What is Mean Failure Rate? (NOV/DEC 2014)
The mean failure rate h is obtained by finding the mean of the failure rates for
specified period of time.
H = (Z1 +Z2 + Z3 + . ... + ZT) / T
Where ZT represents failure rates over the specified period of time.

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8. What is Mean Time between Failures (MTBF)? (MAY/JUNE2015, NOV/DEC 2013
NOV/DEC 2009)
Mean Time between Failures (MTBF) is the mean or average time between
successive failures of a product. Mean time between failures refers to the average time of
breakdown until the device is beyond repair.
9. Define MTTR. (MAY/JUNE 2015)
Mean Time to Repair is the arithmetic mean of the time required to perform
maintenance action. MTTR is defined as the Ratio of total maintenance time and number of
maintenance action.
MTTR = Total maintenance time / Number of maintenance action.
10. Define Maintenance Action Rate? (NOV/DEC 2014)
Maintenance action rate is the number of maintenance action that can be carried out on
equipment per hour.
µ = 1 / MTTR
PART-B
1. (i). State the various objectives and principles of maintenance planning (NOV/DEC
2015, APR 15, MAY 12,NOV/DEC 2009) (8)
Objectives:
The most important objective of the maintenance is the maximization of
availability of equipments and facilities so as to help in achieving the ultimate goals of the
organisation. The following are the objectives of planned maintenance activity:
 To achieve minimum breakdown and to keep the plant in good
working condition at the lowest possible cost.
 To ensure the availability of the machines and services in an
optimum working condition.
 To keep the machines and other facilities in a condition to be used to
achieve the maximum profit without any interruption or hindrance.
 To keep the time schedule of delivery to the customers or to the
sections for further processing.
 To meet the availability requirements for critical equipments.
 To keep the maintenance costs as low as possible for non critical
equipments.
 To control the cost of maintenance related activities

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 To provide effective and trained supervision.
 To meet the quality requirements of the product.
 To increase the profits of production systems.
Principles:
Maintenance principles are followed in a system to guide the staff to work
efficiently and effectively to achieve the overall objectives of the maintenance system.
(i) Plant Management in Maintenance work
The main role of the maintenance function is to provide safe and effective
operation of the equipment to achieve the desired targets on time with
economic usage of resource.
(ii) Production and Maintenance objectives
The plant operation is driven by the production targets. The objective of
maintenance function is to support these targets. The achievement of
desired goals of the production system is to be supported by both the
production and maintenance department to ensure smooth and successful
operation of the industry.
(iii) Establishment of Work order and Recording system
The maintenance system should have proper work order and recording
system. The work order for the maintenance function indicates the nature of
work to be performed and the series of operations to be followed to execute
a particular job. It is necessary to maintain proper records and entries to
monitor the maintenance functions. This record is useful in formulating the
future maintenance plans and scheduling to meet the desired objectives of
the organization.
(iv) Information Based Decision Making
The maintenance objectives are successfully achieved by the use of reliable
information system. This information is used to meet the manpower and
spare parts requirements of the industry.
(v) Adherence to Planned Maintenance Strategy
A sound maintenance management should adheere to the planned
maintenance strategy. This also includes the use of manufacturer’s
information on the life and maintenance schedules of the equipment and
other materials.

10
(vi) Planning of Maintenance Functions
All the maintenance functions are to be carefully executed by a way of
proper planning to ensure the effective utilization of manpower and
materials.
(vii) Manpower for Maintenance
The manpower requirements of the maintenance system must be carefully
evaluated based on the time and motion study. The requirements should
also satisfies the need arising in cases of overhauls, component
replacement, emergency and unscheduled repairs.
(viii) Workforce Control
Determination of exact workforce required to meet the maintenance
objectives of the system is difficult task due to the element of uncertainty.
Hence the proper control and monitoring of workforce are needs to be
ensured.
(ix) Role of Spare Parts
A good maintenance management system requires appropriate tools. So the
system should have good quality tools and that too available in required
quantities to ensure the proper function of the maintenance works.
(x) Training of the Maintenance Workforce
Training of the workforce must be integral part of any good maintenance
management system. Training helps the workforce to learn about the
modern techniques, recent trends in maintenance, knowledge of
sophisticated instruments and to chalk out a strategy to meet the growing
demands of the industry.
(ii) Derive the expression for determining Mean Time to Failure (MTTF) (NOV/DEC
2015, NOV/DEC 2009) (8)
Let t, is the time to failure for the first specimen, t is the time to failure for
the second specimen and tn is the time to failure for the N specimen. Hence the
mean time to failure for N specimens are
HTTF = (t1+t2+.......tn) /n
= 1/N
It is difficult to record the failure for each component when the numbers of
specimens tested are large. Instead, we can record the number which fails

11
during the specific intervals of time.
If n1 is the number of specimens that failed during the first hour, n2 is the number
that failed during the second hour and nk is the number that failed during the kth hour.
Then the mean time to failure for N specimens is
MTTF = (n1 + 2n2 + 3n3 +....knk) / N
It is better to represent the time as interval of the time as such as. Hence the time interval
is ∆t instead of one hour.
Then MTTF is calculated as
MTTF = (n1 ∆t +2n2 ∆t +. ... + knk∆t +..... + lnl ∆t) /N
MTTF = (n1 ∆t +2n2 ∆t +. ... + knk∆t +..... + rnr ∆t) /N
MTTF = 1/N ∑ knk∆t (k = 1 to r)
Where n1 is the number of specimens that failed during the first interval, n2 is the number
of specimens that failed during the second interval and nk is the number of specimens that
failed during the kth
time interval and so on.
2. What are the objectives of maintenance organization and what are the different
types of organizations?(APR 14) (16)
Objectives of Maintenance Organization:
 Identification of organization roles pertaining to maintenance function.
 Determination of maintenance workload.
 Uniform distribution of total maintenance work to all the personal in the
department.
 Identification and assignment of essential works to the various sections of
the maintenance department.
 Proper knowledge about the technical expertise/experience of the workers
deputed for the particular job.
 Proper training of the staff of maintenance to meet the growing demands of
the industry and to catch up with the modern trends in maintenance.
 Designing the policies and procedures at an early stage to help the
maintenance department to achieve the goals of the industry.

12
Types of maintenance organization:
The selection of a type of maintenance system will largely depend on the structure
of an industry. Maintenance organization can be broadly classified into three types as
follows,
(i) Decentralized
This is suitable for large sized plants where inter unit communication is difficult to
get. In this type of organization, the maintenance is under the control of chief engineer of
production to ensure better understanding between the production and maintenance
department.
(ii)Centralized
This is suitable for small units where unit communication is feasible. In this
type of organization, the maintenance is under the control of chief maintenance engineer.
The responsibilities and accountability is with the concerned department heads.
(iii)Partially Centralized
This is the modified version of centralized maintenance organization and suitable
for the industry where units are located at far away locations. In this type of organization,
the maintenance person attached with production unit will carryout the routine
maintenance works. Scheduled maintenance works such as overhauls, planned
maintenance work, procurement of spare parts are under the control of chief maintenance
engineer at the central office.
There are basically two at least two types of organization are followed in most of
the industries. They are,
a. Line organization
b. Line staff organization
Line Organization:
Line organization consists of a general foreman and a number of
specialist foremen with their under them is shown below.
The specialist foreman executes maintenance work in their respective areas while the
general foreman supervises the total work under his control and the various maintenance
tasks carried out in the industry. This kind of structure is an old type maintenance
organization.

13
Line staff organisation:
A few more staff members such as storekeeper and clerk are added to the line
organization to form the line organization structure as given below. The advantage lies in
separating the maintenance work from the store keeping and the role of clerk is to record
the maintenance activities. The recording of maintenance related activities helps the
organization to restructure the strategies adopted to achieve the objectives of
maintenance.
3. (i) Define availability and method of measuring availability. (8)
(Or) What is equipment availability and describe the three basic approaches in detail.
Availability: (APR 16, NOV/DEC 2014)
It is the ratio of the time at which the equipment is available for the designated
operation service to the total time of operation and maintenance of the equipment. It is
also defined as the ration of equipments uptime to the equipment uptime and down time
over a specified period of time.

14
The uptime of a machine / equipment is the time for which it is in actually
available to complete the desired function. The downtime or outage of a machine is the
period of time during which it is not in an acceptable working condition.
The three types of availability are
(i) Inherent availability
(ii) Achieved availability
(iii) Operational availability
Inherent availability:
It is the probability that a system or equipment shall operate satisfactorily
when used under prescribed conditions in a ideal support environment without
any scheduled or preventive maintenance at any given time.
Inherent availability = MTBM/ MTBM+MTTR
Achieved availability:
It is the probability that a system or equipment shall operate satisfactorily
when used under prescribed conditions in an ideal support environment with
periodic preventive and corrective maintenance at any given time.
Achieved availability = MTBM/ MTBM+M
Operational Availability:
In industrial system a certain amount of delay will always caused by time
element such as supply downtime and administrative downtime.
Operational availability = MTBM/ MTBM+MDT
Where MDT is the mean downtime is the satisfied mean of the downtimes
including the supply downtime and administrative downtime.
In general availability of a system is a complex function of reliability,
maintainability and supply effectiveness.
As = f (Rs, Ms, Se)
(ii) Explain maintenance economics. (APR 16, APR/may 14, MAY/JUNE 2012)
Life cycle cost analysis: (8)
The factors to be considered in the purchase of equipment of industries include the
cost, quality, performance and maintenance requirements. Some balance is to be made
between the capital cost and operating cost of the equipment in finding the suitability of
the equipment. The evaluation of any equipment for purchase should be made by keeping

15
into considerations that total cost incurred by the equipment over a span of time say ten
years. Life cycle costing is the cost analysis for the equipment in an industry that
accounts the total cost of the equipment over a span of time which includes the capital
cost, operating cost and maintenance costs. This analysis is the integration of
engineering, economic and financial strategies in relation to the equipment to be
purchased. The aim of life cycle costing is to ascertain the total cost of equipment over
the span of its entire life period.
Advantages of life cycle costing:
Integration of engineering, economics and financial aspects lead to the way of
robust metric for the selection and purchase equipment required for the
industry.
Reduced operating and maintenance cost of equipments due to cost
analysis over span of time.
It leads to the selection of proper and economically viable equipment.
Estimation of economic life of equipment:
The economic life of equipment depends on the maintenance and repair costs,
availability and operational efficiency. A plot of cumulative efficiency and maintenance
and repair cost per cumulative hours Vs operating hours of the equipment to find the
economic life of the equipment.
Maintenance Cost:
Budgets are allocated for all the activities in planning stage itself which includes
the maintenance cost. The cost of maintenance is difficult to measure due to random
nature of failures.

16
The records on maintenance history may be useful in determining the cost. The analysis
of maintenance cost is helpful in taking a decision regarding replacement of a machine or
any of its components.
Maintenance Budget:
The maintenance budget is used to set aside certain amount of money to meet the
expenditures incurred in achieving the objectives of maintenance. The following are the
types of maintenance budget,
(i) Appropriation Budget
Budget used to allocate money for each activity independently.
(ii) Fixed Budget
Fixed used to allocate money for a specified period of time.
(iii) Variable Budget
Dynamic allocation of expendure based on maintenance requirements and
activities.
The evaluation of maintenance cost should consider the following factors:
 The evaluation of maintenance cost should consider the following
factors.
 Cost of maintenance from the recorded data.
 Level and requirements of maintenance.
 Cost of replacement of components and assemblies subjected to wear
and tear.
 Accounting the number of break downs with their levels
 Downtime of the equipment for want of maintenance repair.
 Penalty cost due to loss of production.
 Cost of manpower involved.
 Cost of additional manpower requirement for emergency breakdown
and maintenance.
Cost minimization in maintenance organization:
Centralized planning, scheduling and control
Grouping of specialized workforce
Effective labour utilization strategies

17
Budgetary control and proper check mechanism to implement the cost control
strategies.
Proper and effective use of contract maintenance system to reduce the overhead
costs on equipment and manpower.
Purchase of reliable equipment and spares.
Use of skilled and trained workforce.
Proper selection of suitable type of spares, materials and lubricating.
Proper safety education and formulating the safe practice.
Constant appraisal and education to workforce about the objectives, strategies and
modern techniques adopted in the area of maintenance.
4. (i) State the benefits of a sound maintenance management system (8)
(NOV/DEC 2009)
The profit of any industry depends only on the return of the investment.
The capital cost and operating cost are the major factors involved in any industrial
investment. The life of the equipment and maintenance schedule information provided by
manufacturer may not be realized in practice to make the need for having a sound
management system.
The following are the benefits of sound maintenance management system.
Minimization of colour time.
Improvement in availability of system.
Extended life of equipment.
Safety and smooth operation of the process
Provide adequate back up supply
Minimization of normal expected wear and tear of equipment.
Safety of the personal involved in the organization.
Increased reliability of the system.
Provide proper working environment.
Cost effective maintenance boost the profit of the production system.

18
(ii) Explain the Maintenance Organization structure in detail. (8)
(APR/MAY 2015)
Identifying areas for implementation of preventive maintenance program.
Making suitable arrangements for maintenance facilities for carrying out the
maintenance work properly.
Planning and scheduling the total maintenance work.
Ensuring proper and timely supply of spare parts.
Managing proper inventory control of materials spares and tools required for the
maintenance.
Standardization of maintenance work.
Implementing modifications to the existing equipment whenever possible.
Assisting the purchase department in procuring materials disbursement of services
such as water, electricity, steam, compressed air and other amenities required to
carry out the maintenance.
Identification of obsolete and surplus equipment for replacement and disposal.
Designing the systematic way for disposal of equipment and for maintaining floor
space.
Training of maintenance personnel.
Analysis of future demands and forecast the role of maintenance activities.
Implementation safety norms and procedures.
Ensuring safety of personnel and equipment.
5. (i). State the steps necessary to reduce the maintenance cost in an industry. (8)
(NOV/DEC 2009)
Maintenance should be one of the key strategies to keeping the plant's assets
healthy. While equipment upkeep and parts replacements are necessary, there are
steps that can reduce maintenance costs without decreasing industry processing
facility's operational efficiencies.
a) Examine the necessary things to do and not:
 When first purchasing the equipment in an industry, ensure the review
its maintenance requirements with the manufacturers and the subject
matter experts, whether those are engineers or senior maintenance
professionals.

19
 It should confirm that all of the suggested maintenance is actually
needed, as unnecessary maintenance can actually induce equipment
failure.
 For example, at one of the plant, pumps were undergoing preventive
maintenance every quarter to prevent pump failures. This maintenance
was actually inducing premature failure.
 After engineering performed a detailed root-cause analysis, a different
pump was specified and preventive maintenance was moved to a yearly
event, leading to better system performance and reduced maintenance
costs.
 Benefits: Decreased labour costs, Reduced parts purchases, Increased
the efficiency and overall uptime of the system
b) Select a suitable measurement system:
 Take a compressor, for example. Some companies may think they need
to rebuild a compressor every three years. But what if that compressor
runs only one month out of every four months? You're basing your
preventive maintenance on a calendar year, not on the compressor's
running hours.
 Preventive maintenance should be performed based on the most
applicable measurement system for the equipment.
c) Pick the optimal time to perform maintenance:
 Preventive maintenance should be scheduled maintenance, tuned to the
specific needs of the production schedule.
 This way, processing plant can take assets out of service at a time that
allows maximizing the uptime or efficiency.
 Most companies complete their preventive maintenance in the cooler
months of the year.
 Compressor and evaporator rebuilds are easier to perform in the winter
because the temperatures are not as hot, requiring less of a refrigeration
load. This offsets labour costs, too.

20
d) Maximize the efficiency of the industry staff :
 By training production workers to provide preventive maintenance
assistance on a daily or weekly basis, have to maximize the efficiency of
processing plant staff and take the preventive maintenance burden off of
the senior professionals.
 Preventive maintenance tasks that production workers can complete
include:
Cleaning up the equipment
Inspecting specific items
Watching particular equipment characteristics
 However, once a monitored characteristic is showing signs of needing
preventive maintenance, you need to bring in a subject matter expert to
complete the work or provide additional planning.
e) Develop an overall maintenance strategy:
 Preventive maintenance is only one type of maintenance that should be
part of the overall strategy, including: Preventive maintenance,
Predictive maintenance, Reactive maintenance.
 If preventive maintenance in conjunction with a predictive and reactive
maintenance strategy, maintenance costs can control while managing
downtime and maximizing uptime.
ii) Briefly describe the Accelerated Testing. (ALT) (NOV/DEC 2013) (8)
 Accelerated Life Testing is a method for stress testing of manufactured
products that attempts to duplicate the normal wear and tear that would
normally be experienced over the usable lifetime of the product in a
shorter time period.
 Accelerate cause (something) to happen sooner, Life is the period of
duration, usefulness, or popularity of something, testing means by which
the presence, quality, or genuineness of anything is determined
by means of trial.

21
 Goals of ALT Accelerated Life Testing: Most Important goals of Up
Front Product Life Testing (In-house or Beta Sites) & Data analyses are
to gain information for Fundamental Improvements and Proactive
reliability improvement before Product Release.
 Purpose of ALT: Reliability estimation at user level and dominant
failures mechanism identification.
 Types of accelerated tests: a) ESS and burn-in. b) Qualitative tests, c)
Quantitative tests
 Environmental Stress Screening (ESS):
A process involving the application of environmental stimuli to
products. The goal of ESS is to expose, identify and eliminate latent
defects which cannot be detected by visual inspection or electrical
testing but which will cause failures in the field. ESS is performed on
the entire population and does not involve sampling.
 Burn-in:
Burn-in can be regarded as special case of ESS. It is a test performed for
the purpose of screening or eliminating marginal devices. These devices
are those with inherent defects or defects resulting from manufacturing
aberrations which cause time and stress dependent failures. As with
ESS, burn-in is performed on the entire population.
 Qualitative tests:
An accelerated test that yields failure information or failure modes only
is commonly called a qualitative test or elephant test. Over stressing of
products to “quickly” obtain failures is perhaps the oldest form of
reliability testing. It increases reliability by revealing probable failure
modes.
 Quantitative tests:
Quantitative accelerated life testing, unlike Qualitative testing, is
designed to provide reliability information on the product, component or
system. Data needed in quantitative test is time to failure, such as hours,
days, cycles, miles, actuations etc.
 Common form of ALT is continuous use acceleration. Estimate the life
distribution of the product in a shorter time.

22
UNIT-2
MAINTENANCE POLICIES
PART-A
1. Write the types of maintenance system? (APR 2016)
Basically there are two types of maintenance tasks. They are
I. Break Down (Reactive) Maintenance
II. Planned Maintenance
Planned maintenance may further be classified into
1. Preventive Maintenance
2. Corrective Maintenance
3. Predictive Maintenance
4. Condition Based Maintenance
5. Reliability Centered Maintenance
2. What is meant by Emergency Maintenance? (APR 2016)
It is carried out as fast as possible in order to bring a failed machine or facility to a
safe and operationally efficient condition.
3. What is meant by reliability centered maintenance (RCM)? (DEC 2015)
Reliability centered maintenance 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.
4. What is meant by Breakdown maintenance approach? (DEC 2014)
It is a type of maintenance approach in which equipment is allowed to function/
operate till no failure occurs that no maintenance work is carried out in advance to
prevent failure.
5. Define Corrective maintenance approach and its objectives. (DEC 2014)
Corrective maintenance is the program focused on regular planed tasks that will
maintain all critical machinery and system in optimum operation conditions.
The main objectives are:

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Eliminate breakdowns
Eliminate unnecessary repairs
Optimise all critical plant systems
Eliminate deviations from optimum operation conditions
6. What is meant by planned maintenance approach? (APR 2014)
It is also called Scheduled maintenance. Planned maintenance is a scheduled service
carried out to ensure that equipment is operating correctly and to therefore avoid
any unscheduled breakdown and downtime.
7. Define preventive maintenance? What is the reason it is to be adapted in the
present times. (APR 2015)
It is a maintenance program which is committed to the elimination or
prevention of corrective and breakdown maintenance. It is designed for day to
day maintenance like cleaning, inspection, lubricating, retightening etc. to
retain the healthy condition of equipments.
8. What is complete overhaul? (APR 2016)
Process of restoring and maintaining an equipment, machine, or system in a
serviceable condition. Overhaul involves
(1) Partial or complete disassembly of the item,
(2) Inspection to detect damaged, defective, or worn parts,
(3) Repair or replacement of such parts, and
(4) Reassembly, testing, and trial-run prior to full operating level.
9. Why do you need lubrication? Or what is the use of lubrication? (APR2014)
The primary objective of lubrication is to reduce wear and heat between
contacting surfaces in relative motion. By means of lubrication co-efficient of
friction (which depends on area of contact and amount of load acting) could be
reduced. Lubrication also aids to reduction of rust formation.
10.Define the term Total Productive Maintenance (TPM)? (APR 2015)
Productive maintenance is where the operating personnel are involved in
maintenance of their equipment also. When this concept is extended to all the
employees of the plant shop including materials men, quality men and others and
all the employees work accordingly under consent, it is called “Total Productive
Maintenance"

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PART-B
1. Discuss the different types of maintenance system in detail. (16)
(DEC 2015)
Classification of Maintenance Approach:
Basically there are two types of maintenance tasks. They are
I. Break Down Maintenance
II. Planned Maintenance
Planned maintenance may further be classified into
A) Preventive Maintenance
B) Corrective Maintenance
C) Predictive Maintenance
D) Condition Based Maintenance
E) Reliability Centered Maintenance
BREAK DOWN MAINTENANCE OR REACTIVE MAINTENANCE
 In this category, less attention is given to the operating condition of
critical machinery, equipment or system. Here the equipment is allowed

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to function till no failure occurs no long as the equipment is functioning
at a minimum acceptable level, it is assumed to be effective. This means
the people wait till the equipment fails and repair. This approach of
maintenance is ineffective and extremely expensive. The following
factors contribute to high maintenance costs.
i) Poor planning
ii) Incomplete repair
Limitations:
a) Most repairs are poorly planned due to time constraint caused by production
and plant management. This will cost three to four times than the same repair
when it is well planned.
b) This approach focus only on repair or the symptoms of failure and not on the
root cause of failure. This results only in increase in the frequency of repair
and correspondingly the maintenance costs.
PREVENTIVE MAINTENANCE
 It is a maintenance program which is committed to the elimination or
prevention of corrective and breakdown maintenance. A comprehensive
preventive maintenance program involves periodical evaluation of
critical equipment, machinery to detect problem and schedule
maintenance task to avoid degradation in operating conditions.
Benefits of Preventive Maintenance:
In general the cost incurred towards breakdown maintenance is usually higher than
the cost incurred on preventive maintenance.
It maintains the equipment in good condition to preventing them from bigger
problems.
Prolongs the effective life of the equipments.
Detects the problem at earlier stages.
Minimizes / eliminates the rewash/ scrap and help in reducing the process
variability.
Significantly reduces unplanned downtime.

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CORRECTIVE MAINTENANCE
 Corrective Maintenance is the program focused on regular planned tasks
that will maintain all critical machinery and system in optimum
operating conditions. The effectiveness of this program is judged on the
cycle cost of critical equipment rather than on how quickly the broken
machines are restored to working conditions. It is proactive approach
towards maintenance management.
The main objectives of this program are to
i) Eliminate breakdowns
ii) Eliminate deviations from optimum operating conditions.
iii) Eliminate unnecessary repairs.
iv) Optimize all critical plant systems.
As per this program, all the repairs are well planned and implemented by properly
trained people and the equipment or system is verified and returned to service.
PREREQUISITES OF CORRECTIVE MAINTENANCE:
(i) Existence of trained full time maintenance planners for accurate
identification of roof cause of all incipient problems.
(ii) Properly trained craftsmen with necessary skill to complete the repair of
each incipient problem.
(iii) Standard maintenance procedure for recurring repairs and maintenance
task.
(iv) Allowing sufficient time to maintenance amidst tight production schedules
and management constraints.
(v) A thorough verification process to ensure the completion of repair.
PREDICTIVE MAINTENANCE
 Predictive maintenance is a management technique that uses regular
evaluation of the actual operating conditions of plant equipment,
production systems and plant management functions to optimize total

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plant operation. It is not a solution for all the factors that limit total plant
performance.
CONDITION BASED MAINTENANCE
The various techniques are
Vibration Monitoring –determines the actual condition of equipments / machines
by studying the noise or vibration produced during functioning.
Thermography –determines the condition of plant machinery systems etc by
studying the emission of infra red energy ie temperature.
Tribology –determines the dynamic condition of bearing lubrication, rotor support
structure of machinery etc by adopting any one of the techniques like lubricating
oil analysis, spectrographic analysis, ferrography and wear particle analysis.
Electrical Motor Analysis –determines the problem within motors and other
electrical equipments.
Visual inspection -determines the conditions of working elements visually based
on the experience.
REALIBILITY CENTERED MAINTENANCE (RCM)
 It 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 hw to analyze all failure modes in a system
and define how to prevent or find those failures early. The rough process
of a CM 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 produced or systems are
systematically analyzed.
 Preventive or corrective maintenance operations are considered
selection of operations is done based on rational calculation of
effectiveness of such operations for achieving required maintenance
quality, such as reliability, cost etc.

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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 we are not clear on how they work.
 When teaching people the basics of reliability it helps to explain the matters in a
detailed fashion using RCM.
2. i) Describe the benefits and steps of preventive maintenance.
(DEC 2015) (8)
(a) PREVENTIVE MAINTENANCE
 It is a maintenance program which is committed to the elimination or prevention
of corrective and breakdown maintenance. A comprehensive preventive
maintenance program involves periodical evaluation of critical equipment,
machinery to detect problem and schedule maintenance task to avoid degradation
in operating conditions.
Benefits of Preventive Maintenance:
In general the cost incurred towards breakdown maintenance is usually higher than
the cost incurred on preventive maintenance.
It maintains the equipment in good condition to preventing them from bigger
problems.
Prolongs the effective life of the equipments.
Detects the problem at earlier stages.
Minimizes / eliminates the rewash/ scrap and help in reducing the process
variability.
Significantly reduces unplanned downtime.
STEPS FOR ESTABLISHING A PREVENTIVE MAINTENANCE (PM)
PROGRAM
 There are a number of steps involved in developing a PM program. The figure
presents six steps for establishing a highly effective PM program in a short period.

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Each step is discussed below.
1. Identify and choose the areas:
Identify and selection of one or two important areas to concentrate the initial PM effort.
These areas should be crucial to the success of overall plant operations and may be
experiencing a high degree of maintenance actions. The main objective of this step is to
obtain immediate results in highly visible areas, as well as to win concerned management
support.
2. Identify the PM needs:
Define the PM requirements. Then, establish a schedule of two types of tasks: daily PM
inspections and periodic PM assignments. The daily PM inspections could be conducted
by either maintenance or production personnel. An example of a daily PM inspection is
to check the waste water settle able solids concentration. Periodic PM assignments
usually are performed by the maintenance workers. Examples of such assignments are
replacing throwaway filters, replacing drive belts, and cleaning steam traps and
permanent filters.
3. Establish assignment frequency:
Establish the frequency of the assignments. This involves reviewing the equipment
condition and records. Normally, the basis for establishing the frequency is the
experience of those familiar with the equipment and the recommendations of vendors and
engineering. It must be remembered that vendor recommendations are generally based on
the typical usage of items under consideration.
4. Prepare the PM assignments:
Daily and periodic assignments are identified and described in detail, then submitted for
approval.
5. Schedule the PM assignments on annual basis:
The defined PM assignments are scheduled on the basis of a twelve-month period.
6. Expand the PM program as necessary:
After the implementation of all PM daily inspections and periodic assignments in the
initially selected areas, the PM can be expanded to other areas. Experience gained from
the pilot PM projects is instrumental to expanding the program.

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Figure. Six steps for developing a PM program
ii) Write short notes on RCM and its process. (APR 2016) (8)
(b) RCM (REALIBILITY CENTERED MAINTENANCE) PROCESS
The basic RCM process is composed of the following steps:
1. Identify important items with respect to maintenance:
Usually, maintenance important items are identified using techniques such as failure,
mode, effects, and criticality analysis (FMECA) and fault tree analysis (FTA).
2. Obtain appropriate failure data:
In determining occurrence probabilities and assessing criticality, the availability of
data on part failure rate, operator error probability, and inspection efficiency is essential.
These types of data come from field experience, generic failure databanks, etc.

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3. Develop fault tree analysis data:
Probabilities of occurrence of fault events basic, intermediate, and top events are
calculated as per combinatorial properties of the logic elements in the fault tree.
4. Apply decision logic to critical failure modes:
The decision logic is designed to lead, by asking standard assessment questions, to
the most desirable preventive maintenance task combinations. The same logic is applied
to each crucial mode of failure of each maintenance-important item.
5. Classify maintenance requirements:
Maintenance requirements are categorized into three classifications: on-condition
maintenance requirements, condition-monitoring maintenance requirements, and hard-
time maintenance requirements.
6. Implement RCM decisions:
Task frequencies and intervals are set/enacted as part of the overall maintenance
strategy or plan.
7. Apply sustaining-engineering on the basis of field experience:
Once the system/equipment start operating, the real-life data begin to accumulate.
At that time, one of the most urgent steps is to re-evaluate all RCM-associated default
decisions.
3. Explain the principles and methods of lubrication in detail. (APR 2016) (16)
 In industrial equipments, the surface of the mechanical parts will have physical
contact on the neighbouring parts to establish a relative motion between them.
During operation of the equipments, those contacting surfaces are subjected to
friction which depends on the area of material, properties of material etc which is
undesirable.
 This leads to progressive damage resulting in material loss which is defined as
wear. Friction and wear also generate heat and responsible for the overall loss in
system efficiency. All these contribute to significant economic costs due to
equipment failure, cost for replacement and down time.
 The primary objective of lubrication is to reduce wear and heat between
contacting surfaces in relative motion. By means of lubrication coefficient of

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friction could be reduced and in turn heat and wear of the surfaces. Lubrication
also aids to
(i) reduce oxidation and rust formation
(ii) provide insulation in transformer application
(iii) transmit mechanical power in hydro fluid power systems
(iv) seal against dust, dirt and water.
 Selecting the right lubricant, the right amount of lubricant and the correct
application of the lubricant are essential to the successful performance of
any bearing because bearing lubricants serve three purposes:
(i) To reduce friction by separating mating surfaces.
(ii) To transfer heat (with oil lubrication)
(iii) To product from corrosion and with grease lubrication, dirt ingress
 The success of these three factors depends heavily on the film thickness on
the raceway and at the rib/roller end contact.
Lubricants:
 Any material used to reduce friction between wearing surfaces with high
coefficient of friction, by establishing low-viscous film are called
lubricants. Lubricants are available in liquid, solid and gaseous forms. Solid
lubricants are used for industrial applications when oil or grease are not
suitable. Graphite is used when the loading at the contact points is heavy.
Methods of Lubrication:
The following are the various methods of lubrication normally used for industrial
applications
a) Hydrostatic Lubrication
b) Hydrodynamic or Fluid film lubrication
c) Boundary lubrication
d) Elastic hydrodynamic lubrication (EHD)
e) Extreme pressure (EP) Lubrication

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 In general, the method of lubrication is characterized by the friction and
wears characteristics of wearing surface. Based on the value of ‘R’ which is
defined as follows, the method of lubrication is chosen.
R = Mean fluid film thickness / Surface Roughness (CLA)
Where, R is less than or equal to 1 for boundary lubrication
R is in between 5 and less than or equal to 100 for fluid film lubrication
R is between 1 and 5 for mixed lubrication.
1. Hydrostatic Lubrication:
 In hydrostatic lubrication systems, a thin film of lubrication is created
between the journal and the bearing by supplying lubricant under pressure
with an external source like pump. Since the lubricant is supplied under
pressure, this type of bearing is called externally pressurized bearing.
 Compared to hydrostatic bearing, hydrodynamic bearings are simple in
construction, easy to maintain and lower in initial as well as maintenance.
2. Hydrodynamic or Fluid Film Lubrication:
 In heavily loaded bearings such a thrust bearings and horizontal journal
bearings apart from viscosity of fluid, higher fluid pressure is also required
to support the load until the film is established.

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 If the pressure is generated externally it is called as hydrostatic lubrication
and if generated internally within the bearing by dynamic action, it is
referred to as hydrodynamic lubrication. In hydrodynamic lubrication, a
fluid wedge is formed by the relative surface motion of the journals or the
thrust runners over their bearing surfaces.
(a) Thrust bearings:
 In hydrodynamic lubrication, the wearing surfaces are completely separated
by a film of oil. This type of lubrication is similar to motorized speed
moving on water.
 When not moving the boat begins to move, it experiences a resistance due
to the viscosity of water. This causes a slight lift of leading edge of the boat
and allows a small amount of water between it and supporting water film
increases until a constant velocity is reached.
 When the velocity is constant the amount of water entering the leading edge
equals the amount passing outward from the trailing edge. For the boat to
remain above the supporting surface there should exist a upward pressure
equals to the load. The same principle can be applied to sliding surface.
 The operation of thrust bearing is an example of hydrodynamic lubrication.
Thrust bearing assembly used in hydropower industries are also called tilt
pad bearings. The pads of these bearings are designed to lift and to tilt to
provide enough area for lifting the load of generator.
 As the thrust runner moves over the thrust shoe, fluid adhering to the runner
is drawn between the runner and shoe forming a wedge of oil. As the
velocity of thrust runner increases, the pressure of oil wedge and the runner
is lifted as full fluid film lubrication takes place. When the load is high the
pressure pumps are used to provide initial oil film.
(b) Journal Bearing:
 The operation of a journal or sleeve bearing is also an example of
hydrodynamic lubrication. When the journal is at rest its weight squeezes
out the oil film so that the journal directly rests on the bearing surface

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.
 During operation, the journal has the tendency is drawn into contact area
and when the speed increase an oil wedge increase until the journal is lifted
up vertically but also pushed to the side by pressure of oil wedge. When the
journal is rotating at a constant velocity, film thickness will exist only at the
left centre and not at the bottom of the bearing.
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 or asperities of mating surfaces. This condition is a characteristic of
boundary lubrication.
 This situation arises when anyone of the full film thickness forming factors
are missing. The common examples of this type we experience during
starting and stopping of bearings in equipments. E.g. reciprocating
equipments-compressor pistons, turbine wicket gates, gear teeth contact
etc.
4. Extreme Pressure Lubrication
 Anti wear agents which are normally used in boundary lubrication will not
be effective beyond certain temperature (250 degree Celsius). In heavy
loading applications, oil temperature raises beyond the anti wear protection.

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Under this situation lubricants containing additives that protect against
extreme pressure called EP lubricants are used.
 EP lubrication can be achieved by chemical compounds of boron,
phosphorus, sulphur, chloride or combination of these. These are activated
by high temperature resulting from extreme pressure. At these temperatures
EP molecules become reactive and release derivatives of phosphorous
chloride or sulphur. These derivatives form a solid protective coating that
fills the asperities of the exposed surfaces.
5. Elasto-hydrodynamic (EHD) Lubrication
 The lubrication principle is applicable to rolling bodies such as ball or roller
bearings, is known as Elasto-hydrodynamic (EHD) Lubrication. The
formation of the lubricant film between the mating bearing surfaces is
called the elasto-hydrodynamic (EHD) mechanism of lubrication.
 The two major considerations in EHD lubrication are the elastic
deformation of the contacting bodies under load and the hydrodynamic
effects forcing the lubricant to separate the contacting surfaces while the
pressure of the load is deforming them.
 The contact between the large end of the roller and the inner race rib is
called elasto-hydrodynamic contact or a hydrodynamic contact. As the rib
loads are much lower than the roller loads, the film at the rib end contact is
usually twice as thick as on the roller contact.
 However, scoring and welding may still occur in severe conditions,
including high speeds, viscosity, load or inadequate lubrication. In these
conditions, a lubricant with EP additives is to be used to prevent bearing
damage. Even though the lubrication principle of rolling object is different
from sliding objects, the principle of hydrodynamic lubrication can be
applied up to certain limits. An oil wedge similar to hydrodynamic
lubrication exists at lower leading edge of bearings.
 Adhesion of oil to the sliding element and supporting surface increases
pressure and creates an oil film between two surfaces. Since the area of

37
contact is extremely small in a roller bearing or ball bearing, the force per
unit area will be extremely high. Under this pressure, it would appear that
the oil could be squeezed from between the surfaces. However, the
viscosity increase and prevents the oil from being entirely squeezed out.
4. Discuss the various stages involved in implementation of TPM. (16)
(DEC 2009)
To implement an effective TPM in an organization, the following stages are to be
planned and executed.
STAGE I:
Step-1: Announcement by Management about TPM
Top level management people should attend awareness programs on TPM to have
proper understanding, commitment and active involvement. Then all matters about TPM
should be communicated to others in the company by publishing in the magazine, putting
up in the notice board and by other possible means. In this step a TPM coordinator is
hired or appointed.
Step-2: Initial Education
In this step through educational program is arranged for workforce and is just not
a month program, may even prolong for a year or more.
Step-3: Setting up TPM departmental committees
Since TPM includes improvement, autonomous maintenance and quality
maintenance an action team is formed with people who directly have impact on the
problem being addressed. Operators, maintenance personnel, shift supervisors, schedulers
and top management might be the members of force. This action team should take care of
all those needs.
Step-4: Establishing TPM working system and target
The action team will be assigned with the responsibility of identifying problem
area and detailing course of corrective action and initializing the corrective process. In

38
this step by observing and comparing TPM in other companies a benchmark is set and the
team starts working towards achieving that.
Step-5: A plan for institutionalizing
A master plan leading to institutionalizing, where in TPM becomes an
organizational culture.
STAGE-II - INTRODUCTION STAGE:
A grand ceremony is to be arranged inviting vendors out customers, affiliated
companies, sister concerns and communicating them all that “We care for Quality”.
STAGE-III-IMPLEMENTATION STAGE:
The following activities which are familiarly called as pillars of TPM are carried
out.
 5’S Principle
 Autonomous Maintenance (JISHU HOZEN)
 Planned Maintenance
 Quality Maintenance
 Training
 Office TPM
 Safety, Health and Environment
Stage-I-Intialization
Stage-II-Introduction on TPM
Stage-III-Implementation of TPM
Stage-IV-Institutionalization

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STAGE-IV-INSTITUTIONALIZING STAGE:
Once the action teams are familiar with the TPM process and have experienced
success with small level problems and then with high and complicated problems, the
company can apply for PM award.
5. i) Explain about the repair cycle. (APR 2014) (8)
Repair cycle
 The repetitive performance of all maintenance activities in between two
over hauling is termed as repair cycle.
 The time period for a repair cycle dependent on the time intervals in
between two activities.
The various maintenance activities may be classified into four categories which
are as follows.
Inspection (I)
Minor Repair (R1)
Medium or major (R2) and
Overhauling (O)
 It is clear that first an inspection activity is scheduled followed by minor/
major repair activities.
 Then an inspection takes place followed by a major repair. Again a second
inspection is followed by major repair.
 Like this is goes and completes one repair cycle. The set of these activities
between two consecutive overhauling is defined as a repair cycle.
 This typical repair cycle covers three inspection and two minor and major
repair activities.
 This can be represented O1 –I1 –R11 –R21 –I2 –R1 –I3 R2.
From the above it is understood that the repair cycle is mainly time dependent
between activities.
 An index number generally known as repair completely number is used to denote
the complexity repairing equipments. More the complexity number more will be
the activities involved and in turn more staffing requires completing the repair
cycle.

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ii) Compare TQM and TPM. (DEC 2009) (8)
PILLARS OF (TPM )Total Productive Maintenance:
TPM starts with 5, s principle. Problems cannot be clearly seen when the
workplace is unorganized. Cleaning and organizing the workplace helps the tem to
uncover problems.
5s Seiri –Sort out. This means sorting and organizing the items as critical,
important, frequently used items, useless, or ileins that are not need as of now. Seiton –
Organize Each item has a place and only one place.. the items can be identified early by
writing name plates and coloured tags. `
SEISO –SHINE Their involve cleaning the workplace free of turss, grease, oil,
waste, scrap etc. no loosely hanging wires or oil leakage from machines.
SEIKETSU –Standardization Employees have to discuss together and decide on
standards for keeping the workplace/ machines/ pathways neat and clean. These
standards are implemented for whole organization and are inspected randomly.
SHIFTSUKE –Self Discipline This is to bring about self discipline among
employees of the organization. This includes weaving badges, following work
procedures, punctuality, dedication to the organization etc.
Piller 2 –JISHU HOZEN
Also known as autonomous maintenance. The pillar aims at developing operators
capable of taking care of small maintenance tasks themselves, thus freeing up the skilled
maintenance people to expend time on more value added activity and technical repairs.
Pillar 3 –Kaigen “Kai” means change “Zen means good. Means a continuous
improvement will be there. The above graph shows the continuous improvement.
Pillar 4 –Planned Maintenance It is aimed to have trouble free machines and
equipments producing defect free products for total customer satisfaction. This
maintenance classified into four “families or groups” which were defined earlier.
Pillar 5 –Quality Maintenance It is aimed towards customer delight by getting
them from the highest quality through defect free manufacturing. Focus is on eliminating
non- conformances in a systematic manner. We gain understanding of what parts of the
equipment affect product quality and being to eliminate current quality concerns and then
more to potential quality concerns.

41
Pillar 6 –Training It is aimed to have multi-skilled employees whose morale is
high and who are eager to work and perform all the required functions independent and
effectively.
Pillar 7 –Office TPM It must be followed to improve, productivity, efficiency in
the administrative functions and identify and eliminate losses. This includes analyzing
processes and procedures towards increased office automation. Office TPM addresses
twelve major losses.
Pillar 8 –Safety Health and Environment This pillar aims at achieving i) Zero
accident ii) Zero health damage iii) Zero fires.
1. TPM focuses of equipment which is the input or cause side whereas TQM focuses
mainly on quality & process which are the output or result side of the company.
2. In TQM the small group activities or quality circles are voluntary but in TPM the small
group activities are company led and are integral parts of work-place and organization.
TPM & TQM Similarities:
In many of the aspects, TPM is found to have similarity with the total quality
management (TQM) program.
The following are the similarities between them.
 Empowerment of employees to initiate corrective action, bench marking and
documentation.
 Top level management committed to the program.
 Long range outlook perspective.
The main objectives are to achieving zero defects zero accidents and zero breakdowns in
all functional areas of an organization. Also the objectives include creating different team
of people to have active participation aiming at minimization of defects and to inculcate
autonomous policy.
Dissimilarities:
Category Total quality Management (TQM) TotalProductive
Maintenance (TPM)
Objective To have quality To have reliable equipment
Means of achieving Through systematized Through active participation
of management employees
Target Minimized defective Elimination losses and
Preventive maintenance

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UNIT-3
CONDITION MONITORING
PART-A
1. What are the three types of condition monitoring? (NOV/DEC 2009)
i) Subjective condition monitoring
ii) Aided Subjective condition monitoring
iii)Objective condition monitoring
2. Name the types of pyrometers. (NOV/DEC 2014)
i) Total radiation pyrometers
ii) Infra red pyrometers
iii) Optical pyrometers
3. List down the features of Resistance Temperature Detectors (RTD). (APRIL 2016)
i) High degree of accuracy.
ii) Resistance thermometer is interchangeable in a process without compensation
or recalibration.
iii) It is normally designed for fast response as well as accuracy to provide close
control of processes.
4. What is wear debris analysis? (APR 16, NOV/DEC 2013 )
Concentration and characterization of wear metals and other contaminants,
suspended in used oil, mainly from the machine components, through which the oil
interfaces and generates some wear metals and wear particles.
Contaminants (wear debris or wear particles) generated due to interaction between the
various components / parts of the machine and carried away by the lubricant to sumps,
these are known as Wear Debris Analysis or Contaminant Analysis or Wear Particle
Analysis.
5. Name any four instrument commonly used for condition monitoring methods.
(MAY/JUNE 2012)
i) Visual Inspection
ii) Vibration Monitoring

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iii) Temperature Monitoring
iv) Crack Monitoring
6. What is meant by Thermography? (APR/MAY 2015)
A Thermography technique uses the distribution of surface temperatures to assess
the structure or behaviour of what is under the surface.
Types of Thermography:
i) Passive Thermography
ii) Active Thermography
7. List down the advantages of condition monitoring. (NOV/DEC 2017)
Links between cause and effect
Systems with sufficient response
Mechanisms for objective data assessment
Benefits out weighing cost
Data storage and review facilities.
8.What is shock pulse meter?(May/June 2013)
The meter is used to monitor both oil film thickness and bearing disorder in a bearing
and the conditions to support and maintain oil film thickness.
9.What are the five types of wear?(May/June 2015)
Rubbing wear, Cutting wear, rolling fatigue, combined rolling and sliding wear, Sever
sliding wear.
10. What are the functions of Temperature Sensitive Tapes? (Nov 2017)
A tape having four of five 20 mm diameter dots of special paints, each of which
changes its colour at a particular temperature is stuck to the heat prone parts of the
equipment.
PART-B
1. Describe the various types of Non-destructive testing techniques for condition
monitoring.(APR 15)

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 Various condition monitoring methods have been developed for the past
35years and are in use. A number of strategies and techniques exist for
collecting condition data and interpreting it for taking corrective action.
 The success of condition monitoring depends in the efficiency of
identifying the deteriorating trend in the machine components. For this
purpose, it is essential to recognize the source or cause of failure. There is
variety of technologies that can and should be used as part of a condition
monitoring program. The extensive range of monitoring techniques
available is listed in table.
Type Method On/off line Comments
1.Visual
Inspection
Human eye On/off
Off
Closed circuit
television
(CCTV)
Covers a wide range of highly
effective condition checking and
surface inspection methods.
Can be used for internal inspection of
machines, good for detecting surface
corrosion, wear and severe defects like
cracks.
Permits detailed inspection of
inaccessible environment machine
parts. Image recording and high
resolution analysis is a post-processing
possibility.
2.Vibration
monitoring
Overall
vibration level
Frequency
(spectrum)
Analysis
On
On
Represents the vibration of a rotating
or reciprocating machine as a single,
number which can be trended and used
as a basis for the detection of common
machine faults, but fault diagnosis is
not possible and detection capability
can be compromised.
Represents the vibration of a rotating
or reciprocating machine as a
frequency spectrum which reveals the
discrete frequency component content

45
Shock pulse
monitoring On
(SPM), Spike
energy and
Kurtosis
Structural
monitoring
On
Off
of the vibration. Provides the basis for
fault detection, diagnosis and severity
assessment.
All of these techniques use high
frequency vibration signals to detect
and diagnosis a range of faults
including rolling element bearing
damage, lubrication failure and leak
detection.
A variety of vibration-based
techniques exists for the detection and
location of structural faults. The
majority of such techniques involve
imparting a known vibration into the
structure and analysing the resulting
response.
3.Temperature
Monitoring
Temperature
crayons, paints
and taps
Thermometers,
thermocouples
Infra-red meter
On
On
On
Simple and effective aids to visual
inspection. Can resolve body
temperature to perform from a distance
at a glance.
Range from stick-on thermometric
strips to permanently installed
thermocouple sensors. Can give visual
temperature readout or an electrical
input to a hard-wired monitoring
system.
Non-contacting device which measures
radiated body heat to estimate the
surface temperature of a component.

46
Infra-red
camera
On
Covers a wide range of temperature
but acts only on a small area.
As above but can cover a much wider
surface area. Can provide a detailed
surface temperature picture and can be
calibrated to give quantitative
measurement.
4.Lubrication
analysis
Magnetic plugs
and filters
Ferrography
Spectroscopy
On/Off
N/A
N/A
Analysis of debris picked up by plugs
or filter in an oil washed systems.
Mainly large debris picked up, 100-
1000microns.
Analytical technique used to separate
ferrous debris by size to enable
microscopic examination. Non-ferrous
debris can also be separated but not
graded. A wide range of debris size
can be analysed from 3-100 A
contact service is usually available.
Analytical technique is used to
determine the chemical composition of
the oil and debris. Generally, for small
debris size 0-10 microns. A contract
service usually available.
5.Crack
monitoring
Dye penetrant
Magnetic flux
Electrical
On/Off
On/Off
On/Off
Detects cracks which break the surface
of the material.
Detects cracks at/near the surface of
ferrous materials.
Detects cracks at/near the surface and

47
resistance
Eddy current
Ultrasonic
Radiography
On/Off
On/Off
Off
can be used to estimate depth of crack.
Detects cracks near to surface. Also
useful detection of inclusions and
hardness changes.
Detects cracks anywhere in a
component.
Suffers from directional sensitivity,
meaning that general searches can be
lengthy. Often used to back up other
NDT techniques.
Detects cracks and inclusions
anywhere in a component, although
access to both sides of component is
necessary. Involves a radiation hazard.
6.Corrosion
monitoring
Weight loss
coupons
Incremental
bore holes
Electrical
resistance
Polarization
Off
On
On
On
Coupons are weighed and weight loss
is equated to material thickness loss
due to corrosion.
A series of fine plugged holes of
incremental depths which are
periodically unplugged and scrutinized
for leakage.
Electrical element and potentiometer
are used to assess resistance change
due to material loss. Capable of
detecting material thickness reduction
of loss than 1mm.

48
resistance A good indicator of corrosion but is
unreliable as a means of estimating
material loss rate.
2. i) Explain the principle and working of pistol thermometer. (APR/MAY’ 15,
MAY/JUNE 2012) (8)
 Temperature is the measure of velocity of fluid particles. It is a property which is
used to determine the degree of hotness and coldness or level of heat intensity of a
body.
 Instrument used to measure ordinary temperature – Thermometer.
 Instrument used to measure high temperature – Pyrometer.
 Since pressure, volume, electrical resistance, expansion co efficient are all related to
temperature through fundamental molecular structure, they change with temperature
which can be used to measure temperature.
 Temperature is created when wear, friction, slippage, impact and others occur
between equipments.
 The difference between the ambient temperature and the equipment temperature is
proportional to the defect, which can be detected using the following devices.
Temperature crayons, optical pyrometer, softening cones, bimetallic strips,
thermisters, Thermo transistor, Thermisters, infrared thermograph.
Pistol thermometer (optical pyrometer)
 Thermometers are use to measure the temperature of smaller ranges.
 The range of thermometers is increased to certain limits by using infrared
thermometers.
 Ideal as a professional diagnostic tool for maintenance professionals, the high-end
fluke 576 non-contact, pistol-grip thermometer enables the capture of a simultaneous,
time-stamped digital photographic image as a temperature reading is taken. The logged
results and images from up to 100 locations can be uploaded via a USB connection to a
PC using the windows-based software that comes with the thermometer.
 Thus, the temperature can be stored, presented graphically and analysed, and the
photographic images can be displayed on screen for improved documentation and
maintenance follow-up.

49
 The fluke 576 measures surface temperatures, helping to quickly locate lubrication
problems, overloads, short-circuits or misaligned and overheated equipment
 Reducing work and follow-up time, and improving performance.
 The fluke 576 precision IR thermometer, featuring a true dimension laser sighting
system for precise targeting, is one of the most advanced of its type on the market for
accurate condition monitoring and analysis.
 It measures temperatures between -30 and +900C to a 0.1C resolution with a very
fast response time and a distance to spot ratio of 60:1.
 Features include max/min readings, difference and average readings, and audible
alarms for high and low readings in comparison to 30 preset levels. A bar graph on the
backlit LCD screen displays the last 10 readings.
Pistol thermometer Diagram:

50
ii) How system approach to condition monitoring can be useful? Explain. (MAY 13,
APR 16) (8)
In traditional or holistic approach of condition monitoring, the components of a
equipment are monitored independently. A complete system consists of sub-assemblies
formed of these components. Monitoring of individual components involves recording of
information for result oriented operational control, which is not efficient. This approach
clearly identifies key maintenance and reliability activities, explains their interactions and
how they can be integrated into the whole management process. It enables the
organization of the whole maintenance process rather than focusing on individual
elements or jobs. A good maintenance management process can be considered as having
the following six phases:
 Work identification
 Work planning
 Work scheduling
 Work execution
 History recording
 Analysis
In system approach to maintenance, monitoring of a equipment is done by
considering it as a system. For proper identification and communication of all of the
above six phases, a system approach is developed , it includes proper cataloguing,
codification and computerization of all the actions/activities, assets and materials related
to maintenance of all the departments and work areas and integrating them into one
system. This approach provides an enterprise database that enables to capture and analyze
data about current and historical maintenance work. It also helps keep track of the cost of
maintaining any piece of equipment, work orders and labour time, and key performance
indicators and benchmarks throughout the maintenance operation.
In system approach, a separate sensor is to be used independently, to measure each
characteristics of a component for example, bearings. When this approach is employed,
the output of one sensor can give information, on more than one sub-assembly.
Therefore, monitoring at sub-assembly level reduces the number of sensors, which is the
concept of system condition monitoring technique.

51
3. Explain how cost comparison is done in condition monitoring?(Nov/Dec 2009)
 The cost in maintenance department includes wages, spares, overheads, instrument
and so on. It is difficult to allocate accurate proportion of total cost to individual
maintenance components.
 The spares, labour cost raises and equipment deteriorate with usage, as shown in
figure the there is steady raise in maintenance cost as plant usage increases.

52
 The above diagram represents expenses against savings and final break down
point. The aggregate graph for the cost of the current maintenance situation and
plotted along the expected costs after installing condition monitoring, The area
between two represents potential savings.
 The cost of installation of CM is high in the starting and operation cost becomes
low, but steady during the life of Condition monitoring equipment.
 Introducing Condition monitoring includes both capital and running cost.
Capital cost (Installation):
 The cost includes creative access, installing foundation, covering or protecting,
power supply, service acceptance etc. Consulting cost before and after installation
is also included. The cost of training the operator is also included.
Operating cost:
 The major cost is man power, fuelling, consumables needed.
 Initial cost and saving should result in an early cash outflow for equipment and
training, but soon crosses the breakeven point within acceptable period.

53
 It should then level off into steady profit, it represent satisfying routine on the
initial investment as reduced maintenance cost and improved equipment
performance with overall financial gain.
These are represented in the graph below.
Some of the examples, show the finanical benefits to be gained by implementing
condition monitoring techniques,are as follows:
i) A 25 year old flour mill implemented a planned and condition monitoring and achieved
a 43% saving within 12 months,
ii) An esimated benefit of Rs.160 million has been reported by imperial chemical
industries after implementing permanent vibration monitoring systems at a number of
sites.
iii)The successful implementation of an overall condition monitoring plan by British
Petroleum on one site alone has saved a considerable amount of money.
iv) Taxaco’s Pembrock refinery saved nearly Rs.40,000,000 perpendicular year by
implementing an effective energy monitoring and management programme.

54
4. Discuss the benefits from condition based maintenance.(MAY/JUNE 13)
1. Safety:
The injury and fatal accidents can possibly be reduced by adopting the safety
measures in equipment and system. So, the condition based maintenance enables the
system by indicating the future failure in the form of giving signal to the operator.
2. Extended useful life:
The continuous monitoring enables the system to avoid sudden failures which is
not unscheduled. It extends the life of the equipment considerably.
3. Enhanced availability:
The breakdowns are minimized through proper maintenance which leads to
increase the availability. It is achieved by reducing the down time.
4. Reduction in maintenance time:
The repair time and fault correction time can be reduced by condition based
maintenance.
5. Improved output:
The output of the process is directly linked with the availability, enabled life of the
equipment, reduced maintenance time. The condition based maintenance improves these
three factors which lead to improve the quality of products.
6. Quality product:
The better quality products could be ensured through condition based maintenance
with healthy equipment in the process line. The quality of the products will satisfy the
customer expectation.
7. Improved reliability:
Since the condition monitoring can predict the possible failures, it is possible to
remove or replace a piece of equipment before any series consequences arises and
hence, the reliability of the equipment can be improved.
8. Improved planning:
Condition monitoring also helps in improving maintenance and production
planning. This is due to the fact that the ability to predict the onset of failure
ensures that the organisation of materials and staffing can be carried out in
advance, and fitted into any existing schedules. The reduction in unexpected
failures should reduce the need to reschedule or cancel the existing work.

55
5. What is wear debris analysis? What are the wear debris analysis techniques
commonly used and compare their performance and uses?(NOV/DEC 2015, APR
14)
 Wear debris analysis (WDA) is related to oil analysis only in that the
particles to be studied are collected through drawing a sample of lubricating
oil, wear debris analysis provides direct information about the wearing
condition of the machine train, where as the lubricating oil analysis
determines the actual condition of the oil sample.
 Particles in the lubricant of a machine can provide significant information
about the condition of the machine. This information is obtained from the
study of particle shape, composition, size and quantity.
 Wear debris analysis is normally conducted in two stages. The first method
is routine monitoring and trending of the solid content of the machine
lubricant. The continuous trending of wear rate monitors the performance
of machine and provides early warning and diagnosis.
 In simple terms, the quantity, composition, and size of particulate matter in
the lubricating oil are indicative of the mechanical condition of the
machine. A normal machine will contain low levels of solids with a size
less than 10 micrometers.
 Different mechanical systems have different life and minimum component
wear. International organization for standardization (ISO) set up cleanliness
codes for proper lubricating analysis defined as the number of particles per
millilitre greater than 5,15,25,50 and 100 microns.
 The second method involves analysis of the particulate matter in each
lubricating oil sample is run through a particle counter. The counter passes
the lubricant stream through a beam that measures the number and sizes of
the solid particle contained in the fluid.
 If the wear debris concentration indicates that are too many particles in a
given size range, then further investigation is required. The solid
components are then inspected under a microscope. The results of this test
include particle identification, possible sources, suggestions on corrections,
and picture of the particles.

56
 Five basic types of wear can be identified according to the classification of
particles: rubbing wear, cutting wear, rolling fatigue wear, combined rolling
and sliding wear, and severe sliding wear. The following table summarises
the different types of wear and its description.
SI. No Types of wear Description
1. Rubbing wear Particles<20 micron chord dimension and =1
micron thick. Results from flaking of pieces
from mixed shear layer mainly benign.
2. Cutting wear Swarf like chips of fine wire coils. Caused by
abrasive cutting tool action.
3. Rolling fatigue Chunky, several micron thick from, e.g. gear
wear, 20-50 micron chord width, primary result
of rolling contact bearing failure.
4. Combined rolling and
sliding wear
Typically ferrous, 1 to >10 micron diameter
generated when micro cracks occur under rolling
contact fatigue condition.
5. Severe sliding wear Large>50micron chord width, several microns
thick. Surfaces heavily striated with long straight
edges. Typically, found in gear wear, caused by
excessive loads or heat in the gear system.
WEAR DEBRIS ANALYSIS METHODS
 A wide variety of basic techniques are used in the detection, and evaluation,
of the wear debris present in a lubrication system. The monitoring
equipment which has evolved from these techniques may be used on-line or
off-line. The various basic techniques used are briefly described as follows:
(a) Optical methods:
There are three techniques used by applying optical method.
i) Light of obstruction technique
This technique uses the change in light intensity which occurs when
particle debris pass though a light beam. The intensity change is detected using a
photodiode and the output is calibrated to give the particle size for the flow conditions.

57
Any change in flow conditions and particle properties requires a recalibration of the
instrument.
ii) Time of transition technique
This technique uses a scanning laser beam and is based on the principle that
the time of interaction of a particle within the beam depends directly on the particle size.
The technique is independent of the type of fluid used and therefore does not require
calibration.
iii)Forward reflectance technique
This technique is based upon the reflectance of light at a very shallow angle of
incidence. The light is reflected forward in a narrow angle band, and occurs at an
intensity depending upon the surface area which is impinged by the light beam. This in
turn depends upon the particle size.
(b) Filler blockage:
This technique depends upon the change in the pressure characteristics which
occur when an orifice is blocked by debris within the liquid passing though that orifice.
In practice, screen or mesh is used which consists of a number of same-sized orifices.
Any particles in the fluid which are larger than the orifice size will cause a blockage,
thereby decreasing the flow rate through the mesh.
(c) Magnetic attraction:
This technique uses the magnetic susceptibility of ferrous contaminants to separate
the debris from the carrying fluid. The separation is brought about by a variety of
methods such as the use of a permanent magnet or a magnetic filter. Those instruments
which separate the debris in a manner suitable for further examination and analysis are
generally offline monitors. Magnetic plug method is an on-line debris collector. This
technique collects the ferrous debris from the passing fluid by using magnetized sensing
heads. The debris is allowed to build up over a specified period of time, and the wear rate
is calculated from the weight collected or the change in magnetic flux. The debris is
released back into the system at the end of each measuring cycle by demagnetizing the
collecting zone.
(d) Wear:
This is a technique whereby the electrical resistance of an wear debris contained
within the flowing fluid are allowed to impinges upon the sensor, causing a wearing away
of the sensor material, and hence increasing its electrical resistance. The change in

58
resistance depends upon the rate change in sensor wear and therefore, upon the hardness,
sharpness and frequency of the particles striking the sensor.
(e) Ultrasound:
This technique uses a pulsed ultrasonic acoustical beam focused into a fluid, such
that it will sense the presence of particulate matter within that liquid. Maximum
sensitivity is achieved at the focus of the acoustic beam. Hence, any passing debris will
interrupt the beam and cause a change in the strength of the reflected pulse signal, as seen
by the receiver. The rate of change in the strength of the reflected pulse can be used to
quantify and size the particles present in the fluid stream.
(f) Radioactivity:
This technique involves the monitoring of irradiated wear particles which have
resulted from the wear of an irradiated component. The method is carried out by either,
monitoring the particles using gamma ray detection units within the vicinity of the
irradiated work part, or by monitoring the decrease in radioactivity of the component
itself.
(g) Electrical conductance:
A technique which depends upon the electrical conductivity of the debris within a
non-conducting fluid. The capture of conductive particles between two electrical
terminals results in bridging the gap between them, and this causes a short circuit which
indicates their presence. The capture is brought about by using a magnetic plug
arrangement and therefore the debris must be ferromagnetic.
(h) Image analysis:
Basically a technique involving the computer analysis of video camera images of
dried and cleaned particles extracted from a carrier fluid. The particles are first extracted
using filtration or magnetic separation etc. Onto a substrate for viewing by means of an
optical microscope. The microscope image is translated into an electronic digital picture
through a video camera and an image processing system. The electronic image is then
analysed using computer software techniques to produce information with respect to size,
shape, texture, colour etc.

59
UNIT-4
REPAIR METHODS FOR BASIC MACHINE ELEMENTS
PART-A
1. What is fault or failure analysis? (MAY / JUNE 2013)
Defect analysis or failure analysis is the process by which information / data about
failure occurring in equipments / systems are collected and analyzed to find the root
cause of failures and the causes are addressed to prevent recurrence of failures
2. List the design considerations of guide ways. (NOV/DEC 2009)
The shape of the guide ways is designed based on:
i) Load to be carried by it and direction in which to carry.
ii) Position of transmission element
iii) Characteristics of wear
iv) Ease of chip disposal
3. Differentiate between fault tree diagrams and reliability block diagrams (NOV /
DEC 2009, APR 16)
Sl.
No.
Fault Tree Diagrams Reliability Block Diagrams
1 Fault tree works in the failure space
and looks at system failure
combinations
RBD works in the success space and
thus looks at system successes
combinations.
2 It is used to access fixed probabilities
(i.e. each event that comprises the
tree has a fixed probability of
occurring)
It includes time varying distributions for
the success (reliability equation) and
other properties such as repair /
restoration distributions.
4. How the bearings are repaired? (NOV / DEC 2012)
1. Grinding and polishing of journal surfaces. 2. Periodical change of oil and
filters as recommended. 3. Maintaining a dirt free environment. 4. Shafts and bore

60
produced to exact dimension and geometry. 5. Proper assembly and mounting of
bearings.
5. Discuss the preventive maintenance for bearing. (NOV / DEC 2012)
Lubricant Supply:
The lubricant is the key component of the system which determines bearing life.
Reduced to simplest terms, if a sleeve bearing is provided with an adequate flow of the
proper clean lubricant, long life should be realized.
6.Write down the basic method of repair of gears.(Nov 2017)
Recertification, Reconditioning and Remanufacturing.
7. Define FMEA? (MAY/ JUNE 2013)
FMEA is methodology for analyzing potential reliability problems early in the
development cycle where it is easier to take actions to overcome the issues, thereby
enhancing reliability through design.
8. What are called age-dependent failures? (APR/MAY 2014)
Time dependent failures are called age dependent failures
9. Define Fault tree diagrams (APR/MAY 2014)
Fault tree diagrams are logic block diagrams that display the state of a system in
terms of the states of its components.
10. Write down the capabilities of Fault Tree Diagram. (NOV/DEC 2009)
Fault tree analysis and failure modes and effects analysis,
Design for reliability
Design for safety
11. Define Event tree Analysis (NOV/DEC 2014)
An event tree is a visual representation of all the events which can occur in a
system. As the number of events increases, the pictures fans out like the branches of a
tree.
12. What is meant by Logical Fault Location method? (Nov 2017)
Logical Fault Location method deals with locating the fault in systematic and orderly manner so
as to have a thorough study on cause of fault.

61
PART-B
1. Discuss the repair methods of bearing.( APR 15, NOV/DEC 2009)
Failure Condition Cause Solution
Flaking Raceway surface is
flaked and look
very rough
Rolling fatigue,
overload, poor shaft or
housing accuracy,
installation error,
rusting
Avoid installation error
increasing viscosity of
lubricant and adequate
lubrication.
Peeling Is a cluster of small
spalls
Occur in roller
bearings, if mating
surface is rough and
poor lubrication.
Controlling surface
roughness and dust,
proper selection of
lubricant
Spalling Scratches in
spinning direction
on raceway surface
and rolling contact
surfaces
Poor mounting and
removing practice,
slippage of rolling
elements, oil film
discontinuation
Adopting improved
mounting and removing
procedures, correction of
preload, proper selection
of lubricant and
lubricating systems.
Smearing Surface is
roughened an tiny
particles adhere
Slippage of rolling
elements due to poor
lubricant
characteristics
By making sound oil film,
using extreme pressure
lubricant, precautious on
radial clearance and pre-
load to avoid slippage.
Stepped wear
Worn surfaces and
reduced dimensions
compared to other
portions, mostly
roughed and
scored.
Ingress of solid
foreign objects, poor
lubrication and
skewing of rollers.
Selecting optimum
lubricant and lubrication
system filtering
lubricating oil avoiding
misalignment.
Speckles and Clusters of tiny Poor lubrication, Speckles: Improving

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