ME6012 ME UNIT 1 TO 5 - BY Civildatas.com pec.pdf

SYLLABUS
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.
• 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.
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 off-load
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, slideways, 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. Bhattacharya S.N., “Installation, Servicing and Maintenance”, S. Chand and Co., 1995
REFERENCES:
1. White E.N., “Maintenance Planning”, I Documentation, Gower Press, 1979.
2. Garg M.R., “Industrial Maintenance”, S. Chand & Co., 1986.
3. Higgins L.R., “Maintenance Engineering Hand book”, McGraw Hill, 5th Edition, 1988.
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UNIT I
PRINCIPLES & PRACTICES OF MAINTENANCE PLANNING
Maintenance:
It is the routine and recurring process of keeping a particular machine or asset in its
normal condition o that it can deliver the excepted performance or service without any loss or
damage.
MAINTENANCE PLANNING:
The basic objectives of any planning task are to convert the concepts into workable actions
Types:
1. Long range Planning
2. Short range Planning and
3. Planning for immediate activity
Long Range Planning
 Planning spread over span of five to ten years.
 Goals are set
 Strategies are developed
 Operational programmes are devised for the period of planning.
Short Range Planning
 Prepared by the concerned departments
 Period of time say one to two years
Immediate Activity Planning
 Planning is a routine and is done at the working level as and when required.
Principles of Maintenance Planning
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.
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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 designed targets on time with economic usage of resources.
ii) Production and Maintenance Objectives:
The plant is driven by the production targets. The objective of this maintenance function
is to support these targets.
iii) Information based Decision Making:
The maintenance objectives are successfully achieved by the use of reliable information
system.
iv) Planning of Maintenance Function:
All the maintenance functions are to be carefully executed by a way of proper planning to
ensure the effective utilization of manpower and materials.
v) Manpower for Maintenance:
The manpower requirements of the maintenance system must be carefully evaluated based
on the time and motion study.
vi) 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.
vii) 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.
Important Factors to be considered in Maintenance Planning
o Job Distribution
o Programme
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o Man Power Allocation
o Staffing
o Planning Techniques
o Planning Procedure.
o Maintenance Control
Job Distribution:
The first and foremost task in maintenance planning is the distribution of the pots to the
personnel for preventive and emergence maintenance works.
Programme:
A maintenance programme is a well formulated combination of the available skills and
resources that ensures optimum and appropriate utilization to meet the objective of the
organization.
Man Power Allocation:
It is the most important task of the maintenance management group. The central idea of
man power allocation can be drafted using the information available from maintenance records
and planning the tasks to meet the objectives of the organization.
Staffing:
It is the task of provided the required manpower for the maintenance function. The
advantage of preventive maintenance is that the work can be planned and scheduled properly for
the effective use of resources.
Planning Techniques:
The planning methods are Gantt charts, Critical path method are recently used for
maintenance planning and scheduling.
Maintenance Control:
It is the auditing technique to ensure the effective utilization of the maintenance budget.
This involves the integration of with the system.
Objectives of Planned Maintenance activity
 To achieve product quality and customer satisfaction through adjusted and serviced
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equipment
 Maximize useful life of equipment
 Keep equipment safe and prevent safety hazards
 Minimize frequency and severity of interruptions
 Maximize production capacity – through high utilization of facility
PRINCIPLES OF MAINTENANCE
 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
 Manpower for Maintenance
 Workforce Control
 Role of Spare Parts
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 Training of the Maintenance Workforce
Important and benefits of sound maintenance management system
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.
o Minimization of downtime.
o Improvement in availability of system.
o Extended life of equipment.
o Safety and smooth operation of the process
o Provide adequate back up supply
o Minimization of normal expected wear and tear of equipment.
o Safety of the personal involved in the organization.
o Increased reliability of the system.
o Provide proper working environment.
RELIABILITY IN MAINTENANCE
The concept of reliability has found increased use in industries engineering maintenance
and management.
Need for reliability of Maintenance:
The reliability of a system, equipment and product is very important aspect of quality for
its consistent performance over the expected life span.
Reliability is defined as the probability that ac component / system, when operating under
given condition will perform it intended functions adequate for a specified period of time. It
refers to the like hood that equipment will not fail during its operation. The four important
factors required in the determination of reliability are
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o Reliability expressed as probability
o Adequate performance acquirements
o Duration of adequate performance.
o Environmental or operating conditions.
i) Reliability expressed as probability
It is the ratio of the number of times we can expect an event to occur to the total number
of trail undertaken. A Reliability factor can be expressed as probability. A reliability factor
equal to one means that device performs satisfactorily for the prescribed duration under the
give environmental condition.
ii) Adequate Performance Requiement:
A system may perform satisfactorily even though one or more components may not
be functioning. In reliability analysis there is a need to define the magnitude of satisfactory or
adequate performance of the system.
iii) Duration of Adequate Performance:
The duration of adequate performance is used to state the time up to which the desired
performance of the system is achieved under the given operating conditions.
iv) Environmental or Operating condition:
Environmental conditions indicate the prevailing conditions at which the system is under
operation.
Failure pattern of equipment
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Failure Rate (Z)
Failure rate is the ratio of the number of failures during particular unit interval to the average
population during that interval.
The failure pattern of equipment over its whole life cycle can be represented in the
diagram given below. In phase I, the failure pattern inherent in a new product because of
manufacturing or design defects. Phase II shows the useful life period of an equipment when the
failure rates are normally modulate at the equipment gets set to the working environment. In
Phase III, the failures are excusing due to wear out failure that are caned due to again of the
equipment.
 Reliability (R)
 Maintainability
 Availability
Reliability (R)
Reliability is the probability of a device performing its purpose adequately for the period
intended under the give operating conditions.
Reliability Model:
A basic measurement of the reliability of the product ie its probability of is that of mean
time between failures. Suppose that products are taken at random from a large group and let of
them fail during the time period then the probability of failure during the period “t” is given by
Pt = nt
It is necessary to evaluate the performance of the product over the intended length of time T for
the determination of reliability.
When a large number of products are tested so that the relative frequency becomes a smooth
function f(t) of time. Then reliability expressed by
Rt = 1 –et f (t) dt
Failure rate is approximately constant in that of the practical cases. Then function
assumes the form of the exponential probability function as given by
F (t) = 1/Q e –t/q dt.
Rt = et
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Reliability models:
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Continuous Probability Distribution
 Normal Distribution
 Exponential Distribution and
 Weibull Distribution
NORMAL DISTRIBUTION
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EXPONENTIAL PROBABILITY DISTRIBUTION
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WEIBULL PROBABILITY DISTRIBUTION
 



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
 






 




y
x
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1
PROBABILITY OF FAILURE:
The probability of failure is the ratio of the number of units that failed at specified period of time
to the total population.
Mean Failure Rate (h)
The mean failure rate h is obtained by finding the mean of the failures rates for specified period
of time.
h= (Z1 +Z2 +Z3 +…..+ZT) / T
Where ZT represents failure rates over the specified period of time
Mean Time to Failure (MTTF)
Let tl is the time to failure for the first specimen, t2 is the time to failure for the second specimen
and tn is the time to failure for the Nth specimen. Hence the mean time to failure for N specimens
are
MTTF = (t1+t2+…. +tN) / N
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= 

N
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N 1
1
MTTF IN TERMS OF FAILURE DENSITY
If failure density is given by fd then
fdk = nk / N and
t

fdk = nk / N
t

k is the elapsed time t. Hence the expression for MTTF can be written as
t

MTTF =  

l
dk t
t
k
f
1
)
(
Where the summation is for the period from first interval to the lth interval.
t
 t

Mean time between failures (MTBF)
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.
Mean Time to Repair (MTTR)
Mean Time to Repair (MTTR) 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
Maintenance Action Rate
Maintenance action rate is the number of maintenance action that can be carried out on
equipment per hour.
.
MTTR
1
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
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SERIES RELIABILITY MODEL:
PARALLEL RELIABILITY MODEL
SERIES-PARALLEL RELIABILITY MODEL
Types of Reliability:
Reliability can be generally of two types
Inherent Reliability
It is associated with the quality of the material and design of machine parts
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Achievable Reliability
It depends upon other factor such as maintenance and operation of the equipment.
Maintainability
It is a concept closely related to the characteristics of equipments design and installation.
It is defined as the probability that a unit or system will be restored to specified working
conditions within a given period when maintenance action is taken in accordance with the
prescribed procedures and resources.
Availability
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.
The three types of availability are:
o Inherent availability
o Achieved availability
o 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+MTTF
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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 means of the downtimes including
the supply downtime and administrative downtime.
MAINTENANCE ORGANISATION
The basic objective of the maintenance organization is to ensure that the maintenance
function ae carried out effectively and hence to minimize the production loss due to
maintenance. There has to be a close relationship between the production and maintenance
departments to achieve the desired targets of the industry. Continuous monitoring of planned
preventive maintenance schedules identified for the equipment is required to complete the
maintenance tasks in time.
A maintenance organization can be countered as made up of three basic and necessary
components.
o Resources
o Administration
o Work planning and control system.
Resources
Resources include men, spares and tools involved in the task of maintenance.
Administration
It includes a nearby of authority and responsibility for decision making and plans for the
execution of work.
Work planning and control system
This is the mechanism for planning and scheduling the wok. This also includes the
feedback of information to drive the maintenance effort to its defined objective.
Maintenance of modern equipment and industry requires a healthy, balanced and
rationalized organization, devoted to achieve the goals of maintenance task. The organization
required for any system can be formed after study of the existing continuous and also the future
demands of the industry.
The increasing complexity of present day equipment maintenance management has
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brought into focus two other aspects known as maintainability and availability, both of them are
closely related to reliability.
TASKS OF MAINTENANCE ORGANISATION
The tasks of the maintenance are as follows:
 Identification of organization roles pertaining 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 part
 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.
Maintenance Functions and Activities:
The functions and activities of the maintenance organization are as follows:
 Identifying areas for implementation of preventive maintenance program.
 Making suitable arrangements for maintenance facilities for carrying out the maintenance
works 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
maintenance.
 Standardization of maintenance work.
 Implementing modifications to the existing equipment wherever possible.
 Assisting the purchase department in processing materials.
 Identification of obsdate and surplus equipment for replacement and disposals.
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 Training of maintenance personnel.
 Analysis of future demands and forecast the role of maintenance activities.
 Implementation of safety norms and procedures
 Ensuring safety of personnel and equipment.
Types of maintenance organization
The selections 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 enter unit communication is difficult to get.
In this type of organization the maintenance is difficult to get. In this type of organization, the
maintenance is under the control of chief engineer of production to ensure 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 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 the units are located at far away locations. In this type of organization, the
maintenance personal attached with production unit will carry out the routine maintenance
works. Scheduled maintenance works such as overhauls. Planned maintenance work,
procurement of spare parts is under the control of chief maintenance engineer at the control
office.
There are basically atleast two types of organization are followed in most of the
industries. They are
 Line organization
 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
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carried out in the industry. This kind of structure is an old type maintenance organization.
Line Staff Organization
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 storekeeping 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.
Centrally Controlled Maintenance Organization
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Area Maintenance Organisation
External maintenance service
It is available in two forms contract maintenance service and manufacturers after sale
service.
Advantages of external maintenance service
 It is very economical
 Technically better and specialist are responsible for maintenance activities
 Skill preservation
 Better service
 Updating to modern and existing trends and needs.
Outsourcing in maintenance
The term outsourcing assumed recent importance in the area of computer information
technology and communication due to emergence of business process outsourcing (BPO) is
followed in small industries to hand once the maintenance activities to external agencies.
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This is due to the reason that economy of the industry does not permit to have maintenance
people on their own. It is followed in large industries also ensure maximum control over the
maintenance activities.
Maintenance Economics
Lift cost Analysis:
The factors to be considered in the purchase of equipment for 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.
Life cycle costing is the cost analysis for the equipment in an industry that accounts total cost of
the equipment over a span of time which includes the capital cost, operating cost and
maintenance cost. 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
o Integration of engineering, economics and financial aspects lead to the way of robust
metric for the selection and purchase equipment required for the industry.
o Reduced operating and maintenance cost of equipments due to cost analysis over span of
time.
o 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 of 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
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failures. The words on maintenance history may be useful in determining the cost.
Component of Maintenance Cost
o Fixed cost
o Variable cost
Fixed Cost
This includes the cost of support facilities including the maintenance staff.
Variable Cost
This includes the consumption of spare parts, replacement of components and cost other facilities
required to meet the requirements of maintenance.
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.
Maintenance Budget
The maintenance budget is sued 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 expenditure based on maintenance requirements and
activities.
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Cost Minimization in Maintenance organization
Centralized, planning, scheduling and control.
Grouping of specialized workforce.
Effective later utilization 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 bebricants.
Proper safety education and formulating the safe practice.
Constant appraisal and education to workforce about the objectives, stragies and
modern techniques adopted in the area of maintenance.
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UNIT –II
MAINTENANCE POLICIES – PREVENTIVE MAINTENANCE
CLASSIFICATION OF MAINTENANCE APPROACH
Breakdown Maintenance
In this system the equipment is allowed to function / operate till no failure occurs (i.e) no
maintenance work is carried out in advance to prevent the failure. As 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 repaisir. This approach of maintenance is ineffective and
extremely expensive. The following factors contribute to high maintenance costs.
Poor planning
Incomplete repair
Limitations:
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.
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.
For example when a bearing fails, it leads to production stop. By this approach only the bearing
will be replaced with a nw one, but no attempt will be made to study the cause of failure or to
present a recurrence of this failure. This may seriously affect the reliability of the system.
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Breakdown of an equipment or machine or station in a system will have a significant
effect on the production cost, quality and schedules. For each break down, one or more
operations that are to be performed by that particular machine/ equipment are idled, which in
there delays the completion time of the job. Mean while, parts waiting for this equipment /
machine are to be diverted and assigned to other competing machines are to be diverted and
assigned to other competing machines. Because of this the cost of manufacturing goes up.
Corrective Maintenance
Corrective maintenance is the progress focused on regular planned tasks that will
maintain all critical machinery and system in optimum operating condtions. The effectiveness of
this program is judged on life 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 is to
o Eliminate breakdowns
o Eliminate deviations from optimum operating conditions
o Eliminate unnecessary repair
o Optimize all critical plant systems.
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
 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.
Predictive Maintenance
Predictive maintenance is a management technique that uses regular evaluation of the
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actual operating conditions of plant equipment, production systems and plant management
functions to optimize total plant operation. It is not a solution for all the factors that limit total
plant performance.
Condition Based Maintenance Techniques
o Vibration Monitoring – determines the actual condition of equipments / machines
by studying the noise or vibration produced during functioning.
o Thermography – determines the condition of plant machinery systems etc by studying
the emission of infra red energy (i.e) temperature.
o 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, fessography and wear particle analysis.
o Electrical Motor Analysis – determines the problem within motors and other electrical
equipments.
o Visual inspection - determines the conditions of working elements visually based on the
experience
Reliability 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 how 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 operatious are considered selection of operations is done
based on rational calculation of effectiveness of such operations for achieving required
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maintenance quality, such as reliability, cost etc
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.
Total Productive Maintenance(TPM)
The goal of TPM program is to significant increase the production, at the same time
increasing employee morale and job satisfaction.
The aim of total production maintenance was to maximize plant and equipment
effectiveness to achieve optimum life cycle cost of equipment.
Implementation of TPM
To implement an effective TPM is an organization there are certain stages to be planned and
executed.
Stage I - initialization
Stage II - Introduction on TPM
Stage III - Implementation of TPM
Stage IV – Institutionalization
Stage I Initialization
 Initial education
 Setting up TPM departmental committees.
 Establishing TPM working system and target
 A plan for institutionalizing.
Stage II Introduction
A grand ceremony is to be arranged inviting our customers, affiliated companies, sister
concerns and communicating them that we care for quality.
Stage III – Implementation
There are certain activities which are performed and known as pillars of TPM are carried
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out.
Stage IV Institutionalizing
Once the actions 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.
PILLARS OF TPM
Pillar 1-5s
SEIRI – Sort out.
This means sorting and organizing the items as critical, important, frequently used items, useless,
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 colored tags.
SEISO – SHINE
Their involve cleaning the workplace free of, 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.
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SHITSUKE – 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.
Pillar 2 – JISHU HOZEN
Also known as autonomous maintenance. This 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 – Kaizen
“Kai” means change “Zen means good. Means a continuous improvement will be there.
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.
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 independently 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
 Zero accident
 Zero health damage
 Zero fires.
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TPM & TQM
Maintenance scheduling
It is a joint maintenance operations activity in which maintenance agrees to make the resources
available at a specific time when the unit can also be made available by operations. Resources
include manpower, materials, tools and any special equipment.
The work scheduling should be aimed at to have least adverse effect on normal operating
schedule while optimizing the use of maintenance resources – especially labors.
Stake holders
o Planner
o Scheduler
o Maintenance supervisor
o Craftsmen
o Storeroom personnel
o Operations superintendent
o Operator
REPAIR
Generally, the maintenance scheduling embraces the following activities.
o Inspection
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o Repair
o Overhauling
Repair cycle
To create maintenance scheduling program, the various maintenance activities may be classified
into four categories which are as follows.
o Inspection (I)
o Minor Repair (R)
o Medium or major (R2) and
o Overhauling (O)
The repeated performance of all/ some of the above mentioned activities in sequence between
successive overhauling is termed as Repair cycle. This can be represented o1 – I1 – R11 – R21 –
I 2 – R1 – I3 -R2
LUBRICATION
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 and intern heat and wear of the
surfaces.
o Lubrication also aids to
o Reduction of rust formation
o Reduce oxidation
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o Transmit mechanical power into hydro fluid power systems
o Seal against dust, dirt and water.
Selecting the light and right lubricant, the sight 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.
o Reducing friction by separating mating surfaces.
o To transfer heat (with oil lubrication)
o To protect from correction and with grease lubrication, dirt ingress.
LUBRICANTS
Any materials used to reduce friction with high coefficient of friction, by establishing
low- discus film are called lubricants. Lubricants are available in liquid, solid and gaseous
forms. Solid lubricants (soap, mica, molybdenum disulfide etc) are used for industrial
applications when oil or grease are not suitable. Graphite is used when the loading at contact
points is heavy.
Methods of Lubrication
o Hydrostatic lubrication
o Hydrodynamic or Fluid film lubrication
o Boundary Lubrication
o Elasto hydrodynamic Lubrication (EHD)
o Extreme pressure (EP) lubrication.
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UNIT – III
CONDITION MONITORING
It is one of the maintenance methods which are used to assess the health and conditions
of equipment, machines, systems or process by absorbing, checking, measuring and monitoring
several parameters. This technique is also called as equipment health monitoring (EHM).
Key features of condition Monitoring
The key features of effective condition monitoring system include the following:
(i)Links between cause and effect: A clear relationship mostly exists between the measurement
being taken and the condition of the equipment.
(ii) System with sufficient response: The monitoring system must respond quickly enough to
provide boning of deterioration in machine condition for appropriate action to be taken.
Fundamental steps in Condition Monitoring
 Identifying critical systems
 Selecting suitable techniques for condition monitoring
 Setting baselines / alerts
 Data Collection
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 Data assessment
 Fault diagnosis and repair
 System review
Advantages of Condition Monitoring
 Improved availability of equipment
 Minimized breakdown costs
 Improved morality of the operating personal and safety.
 Improved reliability
 Improved planning
Disadvantages
 Gives only marginal benefits
 Increased running cost
 Sometimes difficult to organize
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Cost comparison with and without condition monitoring.
Instruments used for condition monitoring
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FAULT DIAGNOSIS
Sequential Fault Diagnosis Methods
 Fault location by edge-pin testing
 Generating tests to distinguish faults
 Guided-probe testing
 Fault location by UUT reduction
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Wear Debris Analysis
Sliding adhesive wear particles are found in most lubricating oils. They are an indication
of normal wear. They are produced in large numbers when one metal surface moves across
another. The particles are seen as thin asymmetrical flakes of metals with highly polished
surfaces.
A consequence of periodic stresses with very high local tension in the surface, which
occurs, with the meshing of years. These wear mechanisms give plate particles a rough surface
and an irregular perimeter. Small particles often develop in connection with roller bearings
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UNIT –IV
REPAIR METHODS FOR BASIC MACHINE ELEMENTS
Failures: Even though the meaning of the terms “defect” and failure are identical, defect
is used in border perspective. But in general the term failure refers it malfunctioning, stoppage,
crash and deterioration etc of any equipment or system. As regard to industrial scenario the term
failure may defined as one of the following
Any loss that interrupts the continuity of production
o A loss of asset availability
o The unavailability of equipment
o Any secondary defect
As regard to industries it can be said that the cause of failure of an equipment /system may fall
under any one of the following categories
o Unexpected and unintentional damage-bearing seizure, gear with breakage etc.
o Workmanship-unskilled undivided and rot motivated
o Design- improper design which does not meet the requirement and working
conditions.
o Material- manufacturing defects, mishandling and storage etc.
o Operation-incorrect usage of equipment etc.
Failure models:
It is clear that generally the causes for failure may be predictable and sometimes may not be
possible. So failures are classified as either predictable or unpredictable, in order to select the best
possible maintenance program.
Predictable failure model (age- dependent failures)
Time dependent failures are called age dependent failures. A simplified model of age
dependent model is shown in the graph given below
Unpredictable failure model (purely random failure)
It is experience that most of the components would reach a point of work out failure at the
time of its old age, which a quite common phenomenon similar to age-dependent failure, the
following graph given below that the cause of failure will be random in nature.
Running –in-failure (an early-failure model)
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Suppose if some components/equipments are installed with unnoticed defects, may fail in a
short duration after installation than during its useful life this kind of failure behavior results in
exponential pdf of time-to failure. This by contrast with the negative exponential pdf shows a
single exponential fall off.
Failure analysis methods
FAULT TREE ANALYSIS (FTA or FTD)
Fault tree analysis (FTA) is a top down, deductive failure analysis in which an undesired state of a
system is analyzed using Boolean logic to combine a series of lower-level events. This analysis method is
mainly used in the fields of safety engineering and reliability engineering to understand how systems
can fail, to identify the best ways to reduce risk or to determine (or get a feeling for) event rates of a
safety accident or a particular system level (functional) failure. FTA is used in the aerospace,nuclear
power, chemical and process,pharmaceutical,petrochemical and other high-hazard industries; but is also
used in fields as diverse as risk factor identification relating to social service system failure. FTA is also
used in software engineering for debugging purposes and is closely related to cause-elimination
technique used to detect bugs.
EVENT TREE ANALYSIS (ETA)
Event tree analysis (ETA) is a forward, bottom up, logical modeling technique for both success
and failure that explores responses through a single initiating event and lays a path for assessing
probabilities of the outcomes and overall system analysis.This analysis technique is used to analyze the
effects of functioning or failed systems given that an event has occurred.[ ETA is a powerful tool that will
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identify all consequences of a system that have a probability of occurring after an initiating event that can
be applied to a wide range of systems including: nuclear power plants, spacecraft, and chemical plants.
This Technique may be applied to a system early in the design process to identify potential issues that
may arise rather than correcting the issues after they occur.[With this forward logic process use of ETA as
a tool in risk assessment can help to prevent negative outcomes from occurring by providing a risk
assessor with the probability of occurrence. ETA uses a type of modeling technique called event tree,
which branches events from one single event using Boolean logic.
ROOT CAUSE ANALYSIS (RCA)
Root cause analysis (RCA) is a method of problem solving used for identifying the root
causes of faults or problems. A factor is considered a root cause if removal thereof from the
problem-fault-sequence prevents the final undesirable event from recurring; whereas a causal
factor is one that affects an event's outcome, but is not a root cause. Though removing a causal
factor can benefit an outcome, it does not prevent its recurrence with certainty.
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Repair methods for lathe bed
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Repair methods for lead screws
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UNIT- V
REPAIR METHODS FOR MATERIAL HANDLING EQUIPMENTS
Material handling equipment: It involves the movement of materials, manually or
mechanically within the plant it is a mechanical device for handling of supplies in the greater
ease and economy. The movement may be horizontal, vertical or combination of both.
MHE refers to various materials handling equipments like carts, hand trucks, false lifts,
conveyers and also not limited to self pictures, motorized pullet jacks, track and other specialized
industrial tracks powered by electric motors internal combination engine. Need for maintenance
of material handling equipments: It eases the usage of manual handling and enhances operational
efficiency.
In today’s economic climate of high labour and capital equipment cost, unexpected machine
failures and malfunctions can seriously and relatively impact company profits. The breakdown,
failure or malfunction of material handling equipment can cost a company time and money
material handling maintenance program for MHE will help to maintain the high efficiency and
keep it in running condition this also reduce the cost of expensive repairs as a result of a
breakdown or unnecessary wear, enhanced productivity due to lease machinery downtime and
reduction in the potential for personal injury Maintenance of material handling equipments The
proper maintenance of material handling equipment is extremely essential for preventing the
occurrence of bottle neck or points of congestions production line flow can be maintained only if
the material handling equipments is in proper working order. Out of money maintenance
techniques available preventive maintenance is one of the best maintenance techniques suggested
in case of material handling equipments.
Preventive maintenance helps to keep the material handling equipments always running
conditions there by minimizing the interruption during operation. A periodic inspection and
minor alignments may be adequate to prevent the equipment breakdown. Preventive maintenance
also includes lubrication adjustment and repair. There are three stages of preventive maintenance
and they are
 Inspection
 Repair and
 Overhaul
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Maintenance strategies for hoists and cranes
Portable cranes: The major issues covered in maintenance of portable cranes are:
 It is necessary to keep loads within design limits on portable cranes that are mounted
on wheels or wheeled platforms
 Frequent inspection of crawls, load hosting and lowering mechanism.
 Inspection of boon, base and platform for any sign of store e.g cracks, bends, breaks.
Overhead cranes: The major issues covered in maintenance
 Keep the attachment in overhand crane loaded within the rating capacity.
 Maintain safety factors for replacement pasts according to manufactures
specifications.
 Check welded connection ( e.g main chords and other structural items) for cracks,
bends, abrasion and corrosion
Stages of preventive maintenance cranes
Inspection: All parts, open or covered are infected for wear and tear, worn out or
unworkable components like wire ropes, wheels, hearings, both etc are removed. Breaks are
adjusted and necessary lubrication applied.
Repair: The repairable parts of the system after inspection are corrected for small repairs
and minor defects are rectified. Systems like open gear transmission, coupling, riveted and
looted joints, trolley, breaks, guards etc may be repaired according to the needs.
Overhaul: It involves dismantling the complete mechanism and replacing all damaged
components, crane stratify, buffers, rails, open gear transmission pulley blocks, etc may be
replaced and various sub mechanism may be aligned and adjusted to ensure smooth operation
Maintenance strategies for conveyors:
The major issues covered in maintenance of conveyors are:
 Conveyor system needs to be inspected on a regular basis. The important areas include idlers,
bearings, chains and belts. All of their moving parts are selected to wear and tear.
 Check conveyors detect any belt slippage, dragging or defective welds frequently overlooked
are conveyor rollers, belts, chains regular maintenance procedure. So proper attention is
required for the same.
 Moving equipment parts are subjects to blocks caused by material fatigues loose bearing and
obstructions.
 Checks conveyors regularly to detect any belt slippage dragging a defective rolkers. Control
static electricity through bonding and grounding to minimizing static charges.
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Stages of preventive maintenance for conveyors:
Inspection: Belt or rollers are inspected for tensions, user and tear gear box properly lubricated,
various fasteners are lightened and safety guards are checked.
Repair: Rollers and belts are checked adjusted or repaired couplings, packing, safety guards,
steal structures, gear transmission, learning jolts, threaded components etc are adjusted or
repaired as per their condition and requirements.
Overhaul: The conveyor system is completely dismantled components, wornout and beyond
repair item like belts, bearings, packing, oil, sealers, rollers, drancs, fasteners and and coupling
are replace Structures and safety guards may be repaired as per their conditions.
Typical scheduled conveyor maintanence plan
 Check/lubrication in all bearings, universal joints and pulleys
 Check chain tension, wear and lubricate
 Check sprocket alignment wear and screw set
 Check flat belt tension, wear and lacing
 Check v-belt tension wear share alignment
 Check electrical connections
Forklifts:
The major issues cared in maintenance of forklifts are
 Forklifts require a daily inspection for proper operation. Daily checkd wheels, brakes,
forks, chains, hydraulics, steering horn & fuel.
 Fork lifts with engine should be checked for coolant and engine oil levels.
 Inspect trucks carefully for signs of excessive wear and tear
 Remove accumulations of grease dirt
 Scheduled maintenance based on engine hour or motor hour experience may reduce
malfunctions.
 Give special attension to breaks limit switches, trolley wheels, load hooks, castes and
chairs. These needs to be examined for evidence of wear, malfunction, damage and
proper operation.
 Inspect sheares ruts, bolts, clamps, braces, hooks and scriber parts monthly or more
frequently. Depending upon usage
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Important points in maintenance of MHE:
 Training is the key to safe material handling and the operation of equipment being used
to complete the job.
 Training will help to reduce unnecessary damage to equipment and prevent personal
injury to employes.
 Selecting the right equipment for the jobs is also important task.
 For example selection of proper fork lifts for work inside a closed warehouse.
 The obrious choice would be an electric fall lift to avoid carton monoside explore from
the exhast.
 Another example is selecting a hand truck for rough ground or floor conditions.
 This case with rough ground or floor conditiona hand trucks with lager preumatic wheels
would be the right choice.
 There is no single, complete maintenance program which will fit all your needs.
System approach to maintenance:
The proper operation of on industry requires appropriate strategies in maintenance management.
This is ensured by the effective integration of various phases involved in management.
• Planning
• Scheduling
• Execution
• Reworking and
• Analysis
Six phases of good maintenance management
 Work identification
 Work planning
 Work scheduling
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 Work execution
 History recording
 Analysis
Computerized maintenance management system (CMMs)
There is a need to integrate the decision support tools in maintenance function. Support tools in
maintenance planning and execution for the efficient discharge of the maintenance function.
There is an increasing trend in application of information based decision support systems in
different departments of modern
o Thus computers have become an indispensable requirement in maintenance
management Computer is an efficient and reliable tool for maintenance personal
to plan and implement their programmers.
o The success of CMMS depends on the quality of integration of computer system
in maintenance management.
o Computerized maintenance management system (CMMS) is used to track all
maintenance costs and equipment repairs.
o This tracking is accomplished by the monitoring of work orders.
o This task will provide necessary information to track and plan and maintenance
budgets.
Aspects of CMMS
 Development of a database
 Analysis of available part records
 Development of maintenance schedules
 Availability of maintenance arterials
 Feedback control system
 PEM
 Project management.
Advantages of computerized maintenance management system
The features in the computerized maintenance management system provide the following
advantages to the user:
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Improve maintenance efficiency
Reduce maintenance asks
Reduce the equipment downtime by proper scheduling
Reduce the overtime and ensure optimal utilization of man power
Increase the lift of equipment
Provide historical database to assist in maintenance planning and budgeting
Provide maintenance reports in specific formats depending on the requirements.
Quicker access the plant maintenance statistic
Conformity with health and safety standards
General structure of computerized maintenance management system
Most computerized maintenance management systems accomplish this objective through the
use of four system modules. They are:
 Work order planning and scheduling
 Maintenance store contracts
 Preventive maintenance
 Maintenance reports Work order planning and scheduling:
Computerized work orders are documents that detail maintenance works. The computerized
work orders should contain information such as
i) Work order
ii) Details of equipment for which work is requested
Work order entry
The general work order entry requires the following information to be filled by the user:
 Equipment number that requires maintenance
 Priority and description of the work
 Estimated cost of work
 Information for dependent or associated work tasks for a complex maintenance job
JOB CARDS AND JOB CARD PROCEDURES
Informations provided by JOB CARD
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 Equipment code and shop code
 Job code
 Nature of job & job details
 Initiation time of start and completion time
 Man hours spent
Benefits of job card system
The following are the benefits and advantages of job card system
 information about maintenance history
 knowledge of frequency of maintenance for equipments
 details of equipment which require maintenance resources
 help in job auditing evaluation of costs of maintenance
 information about equipment downtime
 estimation of loss of production
 idea about man power utilization
Equipment records
They are information containing the details of installation service repair, maintenance
activities; conditions, defects, schedules and plans for future implementation equipment records
are to be used to maintain control on maintenance cost, reliability and availability.
Types of equipment records
They are many types of equipment records available in industry catering to various needs. They
are as follows:
 planned work and percentage to planned work achieved
 ratio of planned to planned work
 production delays & downtime
 ratio of preventive work to corrective work
 failure patterns
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 repetitive breakdown
 manuals including operating manual, instruction manual, maintenance manual, job
manual and drawings
 history cards and records
 spall cards
 maintenance requirement records
 performance details
 cost reports
 condition monitoring reports
Maintenance work execution, monitoring and control
A well designed organization should have proper strategies to execute, monitor and control over
the various maintenance tasks
Monitoring:
The role of monitoring in maintenance has the following advantages:
 Gather information about derivation and delay in execution of maintenance may provide
idea about the need to add more resources to complete the maintenance tasks in
scheduled time frames
 Communication of the changes in jobs content to the various follow up agencies.
 Provide information about constraints in technical issues and necessary steps can be
taken to improve the existing techniques
 Provide a lead to implement technical advancement and methodologies in future to
complete the tasks in more efficient manner.
Control:
The system shows the interaction between shop supervisors and maintenance executes.
After the constraints of material or resources met, unfinished maintenance tasks will be executed.
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