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.

1. RAMCO INSTITUTE OF TECHNOLOGY
Mr.M.LAKSHMANAN
Assistant Professor (Senior Grade)
Department of Mechanical Engineering

3. UNIT I
PRINCIPLES AND PRACTICES OF
MAINTENANCE PLANNING
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.

4. UNIT II
MAINTENANCE POLICIES –
PREVENTIVE MAINTENANCE
Maintenance categories – Comparative merits
of each category – Preventive maintenance,
maintenance schedules, repair cycle -
Principles and methods of lubrication – TPM.

5. UNIT III
CONDITION MONITORING
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

6. UNIT IV
REPAIR METHODS FOR BASIC
MACHINE ELEMENTS
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.

7. UNIT V
REPAIR METHODS FOR MATERIAL
HANDLING EQUIPMENT
Repair methods for Material handling
equipment - Equipment records –Job order
systems -Use of computers in maintenance.

8. Course Objectives
1. To learn the principles and practices of
maintenance planning
2. To understand the maintenance policies –
preventive maintenance
3. To familiarize the condition monitoring
4. To study the repair methods for basic machine
elements
5. To identify the repair methods for material
handling equipment

9. Course Outcomes
After completion of the course,
1. Describe the basic principles in maintenance.
2. Identify the role of preventive maintenance
3. Summarize the various processes involved in
condition monitoring
4. Explain the influence of failure analysis in basic
machine elements
5. Compute the principles of material handling
equipment and the use of computers in
maintenance

10. UNIT I
PRINCIPLES AND PRACTICES OF
MAINTENANCE PLANNING

11. Definition of Maintenance
Maintenance is the routine and recurring process
of keeping a particular machine or asset in its
normal operating condition so that it can deliver
the expected performance or service without any
loss or damage.
The responsibility of the maintenance function
should be to ensure that production
equipment/facilities are available for use for
maximum time at minimum cost within
stipulated period.

13. Maintenance Engineering
Maintenance Engineering is the discipline
and profession of
applying engineering concepts to the
optimization of equipment, procedures, and
departmental budgets to achieve
better maintainability, reliability, and
availability of equipment.

14. Concept of Planning
Planning ensures the smooth operation
system. For effective working of any system, it
is necessary to plan and schedule its activities.
• Long range planning
• Short range planning
• Planning for immediate activity

15. Maintenance Planning
• It’s the task of organizing resources to
carryout a job satisfactorily at reasonable
cost within a specified period of time.
• Its able to tackle the emergency
maintenance as well as to ensure that
maintenance workforce is fully utilized.

16. Objectives of Maintenance Planning
• 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 time schedule of delivery to the
customers.
• To control the cost of maintenance related
activities.
• To increase the profits of production systems.

17. Principles of Maintenance
1. 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 resources.
2. Production and Maintenance Objectives
The plant operation is driven by the production
targets. The objective of maintenance function is to
support these targets. To ensure production and
maintenance departments are supporting for
successful operation of the industry.

18. 3. Establishment of 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.
4. Information Based Decision Making
Information system is used to meet the
manpower and spare parts requirements of
the industry.

19. 5. Manpower for Maintenance
The manpower requirements of the
maintenance system must be carefully
evaluated based on the time and motion study.
6. Workforce Control
Determination of exact workforce required to
meet the maintenance objectives of the
system is difficult task due to element of
uncertainty.

20. 7. 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.

21. Important Factors to be considered in
Maintenance Planning
• Job Distribution
• Maintenance Programme
– Selection of Activities
– Determination of Frequency of Maintenance
– Decision on the cost effective methodology
• Manpower Allocation
• Staffing
• Planning Techniques
• Planning Procedure
• Estimation of Maintenance Works
• Maintenance Control

22. Importance and Benefits of Sound
Maintenance Management System
• Minimization of downtime.
• 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

23. Reliability
• 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.
• The ability of an apparatus, machine, or system
to consistently perform its intended or
required function or mission, on demand and
without degradation or failure.

24. Failure pattern of Equipment
Equipment Life Cycle

25. Failure Density
• Failure Density is the ratio of the number of
failures during a given unit interval of time
to the total number of times at the very
beginning of the test.
• Let n1 be the number of components that
fail during the first unit interval and so on.
• N - Population

27. Failure Rate (Z)
• Failure rate is the ratio of the number of
failures during particular unit interval to the
average population during that interval.
• This failure rate is also known as hazard
rate and instantaneous failure rate.

28. Reliability (R)
• Reliability is the probability of a device
performing its purpose adequately for the
intended under the given operating
conditions.
• Reliability is the ratio of the survivors at any
given time to the total initial population.

29. Reliability Model
The probability of failure during the period t is given
by

31. Common modes of Failures in industries

34. Continuous Probability Distribution
A Probability distribution of the variable data
is known as Continuous Probability
Distribution. The Commonly Used are
• Normal Distribution
• Exponential Distribution
• Weibull Distribution

35. Normal Distribution
µ Average Population
σ Standard Deviation

38. Exponential Distribution

40. Weibull Distribution

42. 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)
MFR h is obtained by finding the mean of the
failures rates for specified of time.
Where ZT represents failure rates over the
specified period of time T.

43. Mean Time to Failure (MTTF)
Mean time to failure for N Specimens are

45. Mean Time Between Failures(MTBF)
MTBF is the mean or average time between
successive failures of a product. MTBF refers
to the average time of breakdown until the
device is beyond repair.

46. Mean Time to Repair (MTTR)
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

48. Maintenance Action Rate
Number of maintenance action that can be
carried out on equipment per hour.
µ = 1
MTTR

49. Types of Reliability
• Inherent Reliability:
It is associated with the quality of the material
and design of machine parts
• Achievable Reliability:
It depends upon other factors such as
maintenance and operation of the equipment.

50. Maintainability
• Maintainability is a concept closely related to
the characteristics of equipment design and
installation.
• Maintainability is defined as the probability of
performing a successful repair action within a
given time.
• Maintainability 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.

52. Availability
• Availability is the ratio of the time at which
equipment is available for the designed
operation/ Service to the total time of
operation and maintenance of the
equipment.
• Its also defined as the ratio of equipment
uptime to the equipment uptime and
downtime over a specified period of time.

53. Types of Availability
• Inherent Availability
It’s the probability that a system or equipment
shall operate satisfactorily when used under
prescribed conditions in an ideal support
environment without any scheduled or
preventive maintenance at any given time.
Inherent Availability = MTBM
MTBM + MTTR

54. • Achieved Availability
Achieved availability 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’
Where M’ is the mean active maintenance
downtime resulting from preventive and
corrective maintenance.

55. • Operational Availability
Operational Availability is the probability that
a system or equipment shall operate
satisfactorily when used under prescribed
conditions in an actual supply environment
without any scheduled or preventive
maintenance at any given time.
Operational Availability = MTBM
MTBM + MDT
Where MDT is the Mean Down Time is the
statistical mean of the downtimes including
the supply downtime and administrative
downtime.

56. 1. Calculate the failure rate of a components
from the following data:
Number of component tested = 750
Period of Time = 1000 hrs
No. of failures reported for the given period of
time = 5
ANS:
λ = 6.67x10-6 Failures/hr
R = 99.34%
F = 0.66%

57. 2. In a process plant, it is desired to have a
reliability of at least 0.980 for a specified
period of 5000hrs for the successful
operation of a machine. Calculate the mean
life or mean time between failures (MTBF)
of the equipment.
ANS:
Θ = 247432.88 hrs

58. TASKS OF MAINTENANCE ORGANIZATION
• 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
experience of the workers deputed for the
job.

59. • 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.

60. Types of Maintenance Organization
• Decentralized
• Centralized
• Partially Centralized
Basic Types
1. Line Organization
2. Line Staff Organization

61. Line Organization

62. Line Staff Organization

63. Maintenance Functional Organization

64. Centrally Controlled Maintenance
Organization

65. Area Maintenance Organization

66. General Organization Structure of
Maintenance Department

67. External Maintenance Services
• It is very economical.
• Technically better and specialist are
responsible for maintenance activities.
• Better service
• Updating to modern and existing trends and
needs.

68. Advantages Outsourcing in Maintenance
• Cost of maintenance is minimized
• No need for having maintenance as a
department
• Better quality of service achieved through
employing specialists
• Better maintenance practices

69. Maintenance Economics
• Life Cycle cost Analysis:
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.

70. 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.

71. Estimation of Economic Life of
Equipment

72. Maintenance Cost
• The cost of maintenance is difficult to measure due
to random nature of failures.
• The analysis of maintenance cost is helpful in
taking a decision regarding replacement of a
machine or any of its components.

73. Component of Maintenance cost
• Fixed Cost
• Variable Cost

74. Factors considered for evaluation of
Maintenance Cost
• Cost of maintenance from the recorded data
(Past experience)
• Cost of spare parts and materials
• Cost of replacement of components and
assemblies in wear and tear.
• Accounting the number of breakdowns with
their levels
• Cost of manpower involved
• Cost of additional manpower requirements for
emergency breakdown and maintenance.

75. Maintenance Budgets
• Appropriation Budget
• Fixed Budget
• Variable Budget
Factors to be considered in preparation of
Maintenance Budget
• Proper judgment of repair or replacement
• Comparison between inhouse maintenance and
hired maintenance.
• Equipment Overhaul periods.
• Cost of obsolescence.

76. Cost Minimization in Maintenance
Organization
• Centralized planning, scheduling and control
• Effective labour utilization strategies
• Purchase of reliable equipment and spares.
• Proper selection of suitable type of spares,
materials and lubricants.
• Proper safety education and formulating the safe
practice.

77. • Mechanical maintenance engineer skills and
specifications
https://www.youtube.com/watch?v=wTvkO9Rym3
A
• Mod-01 Lec-02 Maintenance Principles
https://www.youtube.com/watch?v=f58SW0Hwcf0