1. Maintenance Engineering (ME6012)By
Karthikeyan.I
Asst.Professor
Department of Mechanical Engineering
Sri Ramakrishna Engineering College,Cbe

2. 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.

3. OUTCOMES
Upon completion of the programme, the students can able to implement the maintenance function and different practices in industries for the successful management of maintenance activities
To identify the different maintenance categories like Preventive maintenance, condition monitoring and repair of machine elements

4. TEXT BOOKS: 1. Srivastava S. K
TEXT BOOKS: 1. Srivastava S.K., “Industrial Maintenance Management”, S. Chand and Co., Venkataraman .K “Maintancence Engineering and Management”, PHI Learning, Pvt. Ltd., 2007 REFERENCES: 1. Bhattacharya S.N., “Installation, Servicing and Maintenance”, S. Chand and Co., White E.N., “Maintenance Planning”, I Documentation, Gower Press, Garg M.R., “Industrial Maintenance”, S. Chand & Co., Higgins L.R., “Maintenance Engineering Hand book”, 5th Edition, McGraw Hill, Armstrong, “Condition Monitoring”, BSIRSA, Davies, “Handbook of Condition Monitoring”, Chapman & Hall, “Advances in Plant Engineering and Management”, Seminar Proceedings - IIPE, 1996.

5. Unit 1-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

6. Maintenance Engineering
It is the art that is intended to retain an machine or an equipment or restore it to, a state in which it can perform a required function or an operation.
It is the discipline and profession of applying engineering concepts to the optimization of equipments, procedures to achieve better reliability and availability of equipments.
It is the art, science and philosophy that aides in increased productivity and has become the most important component of plant maintenance.

7. In general,
All actions necessary for retaining an item, or restoring to it, a serviceable condition, include servicing, repair, modification, overhaul, inspection and condition verification.
Increase availability of a system.
Keep system’s equipment in working order are the main role of maintenance Engineering.

8. It’s purpose
The main purpose of maintenance in an industrial perspective is to reduce the business risks.
Production capacity, productivity and business profit mainly depends on maintenance operations.
Its main purpose is to support ,configure, diagnose , repair, update and mange a equipment throughout it’s life cycle.
In general maintaining all equipments at its full functionality and helping productivity is the main function of maintenance engineering.
Attempt to maximize performance of production equipment efficiently and regularly.
Prevent breakdown or failures.
Minimize production loss from failures.
Increase reliability of the operating systems.

9. With the increased complexity, Sophistication and automation of the equipments and systems , a heavy burden falls on maintenance engineers regarding the quality and quantity of maintenance , maintenance aids, documentation etc.,
The current scenario is that today’s jobs and problems cannot be solved with yesterday’s tools and techniques. So continuous development is needed in maintenance areas to tackle today’s need and also anticipated need of tomorrow.

10. Principle Objectives in Maintenance
To achieve product quality and customer satisfaction through adjusted and serviced equipment.
Maximize useful life of equipments.
Keep equipments safe and prevent from hazards.
Minimize frequency and severity of interruptions.
Maximize production capacity – through high utilization of facility.

11. MAINTENANCE FACTS AND FIGURES
Some of the important facts and figures directly or indirectly associated with engineering maintenance are as follows:
Each year over $300 billion are spent on plant maintenance and operations by U.S. industry, and it is estimated that approximately 80% of this is spent to correct the chronic failure of machines, systems, and people.
In 1970, a British Ministry of Technology Working Party report estimated that maintenance cost the United Kingdom (UK) was approximately £3000 million annually.

12. Annually, the cost of maintaining a military jet aircraft is around $1
Annually, the cost of maintaining a military jet aircraft is around $1.6 million; approximately 11% of the total operating cost for an aircraft is spent on maintenance activities.
The typical size of a plant maintenance group in a manufacturing organization varied from 5 to 10% of the total operating force: in 1969, 1 to 17 persons, and in 1981, 1 to 12 persons.
The U.S. Department of Defense is the steward of the world’s largest dedicated infrastructure, with a physical plant valued at approximately $570 billion on approximately 42,000 square miles of land, i.e., roughly the size of the state of Virginia.

13. The operation and maintenance budget request of the U. S
The operation and maintenance budget request of the U.S. Department of Defense for fiscal year 1997 was on the order of $79 billion.
Annually, the U.S. Department of Defense spends around $12 billion for depot maintenance of weapon systems and equipment: Navy (59%), Air Force (27%), Army (13%), and others (1%).
In 1968, it was estimated that better maintenance practices in the U.K. could have saved approximately £300 million annually of lost production due to equipment unavailability.

15. 1.Maintenance Planning
Maintenance planning consists of set of tasks of organizing resources to carry out a job satisfactorily at reasonable cost within a specified period of time.
It involves
Assignment of jobs to the crew on the basis of job scheduling.
Also ensures methods to tackle emergency maintenance
It ensures smooth operation of the system.

16. Main classification of planning in engineering system are as follows,
Long range planning
Short range planning
Planning for immediate activity
1. Long Range planning : for a period of five years at least. Involves capital budgeting, strategies and operational programmers.
2. Short range: up to one year. Made to achieve short term goals.
3. Immediate Activity Planning : it is done frequently whenever required.

17. Objectives of maintenance planning
Some important objectives are
Maximising production or increasing facilities availability at the lowest cost and at the highest quality and safety standards.
Reducing breakdowns and emergency shutdowns.
Optimising resources utilisation.
Reducing downtime.
Improving spares stock control.
To keep time schedule of delivery to the customers.
To control the cost of maintenance related activities.

18. Improving equipment efficiency and reducing scrap rate.
Minimising energy usage.
Optimising the useful life of equipment.
Identifying and implementing cost reductions.
To provide effective and trained supervision.

20. Principles of Maintenance :
They are followed in a system to guide the staff to work efficiently and effectively to achieve the overall objectives of the maintenance system,
Main areas of work governed by this principles are
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 .
Manpower for Maintenance
Planning for maintenance functions
Role of Spare parts
Training.

21. Sound maintenance system-importance
Profit depends mainly on return on the investments.
Higher investments- possible –machineries and equipments in proper working condition.
Some benefits of sound maintenance are,
Minimization of downtime
Provide Adequate back up supply
Extended life of equipment
Increased reliability of the system
Safety of the personal involved.

22. 2.Machine Failures

23. Reliability Reliability may be defined in several ways:
The idea that an item is fit for a purpose with respect to time.
In the most practical sense: "Items that do not fail in use are reliable" and "Items that do fail in use are not reliable".
The capacity of a designed, produced or maintained item to perform as required over time.
The resistance to failure of an item over time.

24. The probability of an item to perform a required function under stated conditions for a specified period of time.
In line with the creation of safety cases for safety, the goal is to provide a robust set of qualitative and quantitative evidence that an item or system will not contain unacceptable risk.
The basic sorts of steps to take are to:
First thoroughly identify as many as possible reliability hazards (e.g. relevant System Failure Scenarios item Failure modes, the basic Failure mechanisms and root causes) by specific analysis or tests.
Assess the Risk associated with them by analysis and testing.

25. Propose mitigations by which the risks may be lowered and controlled to an acceptable level.
Select the best mitigations and get agreement on final (accepted) Risk Levels, possible based on cost-benefit analysis.
RELIABILITY THEORY
Reliability is defined as the probability that a device will perform its intended function during a specified period of time under stated conditions.
Mathematically, this may be expressed as,
Where is the failure probability density function and is the length of the
period of time (which is assumed to start from time zero).

26. MEAN TIME BETWEEN FAILURES
Mean time between failures (MTBF) is the predicted elapsed time between inherent failures of a system during operation. MTBF can be calculated as the arithmetic mean (average) time between failures of a system.

27. The MTBF is often denoted by the Greek letter θ, or
The MTBF can be defined in terms of the expected value of the density function ƒ(t)
where ƒ is the density function of time until failure – satisfying the standard requirement of density functions

29. MTBF value prediction is an important element in the development of products. Reliability engineers / design engineers, often utilize Reliability Software to calculate products' MTBF according to various methods/standards (MIL-HDBK-217F, Telcordia SR332, Siemens Norm, FIDES,UTE (RDF2000), etc.).

30. MTTR
The M can stand for any of minimum, mean or maximum, and the R can stand for any of recovery, repair, respond, or restore.
The most common, mean, is also subject to interpretation, as there are many different ways in which a mean can be calculated.
Mean time to repair
Mean time to recovery/Mean time to restore
Mean time to respond
Mean time to replace

31. Mean time to repair (MTTR) is the average time required to troubleshoot and repair failed equipment and return it to normal operating conditions.
It is a basic technical measure of the maintainability of equipment and repairable parts.
Maintenance time is defined as the time between the start of the incident and the moment the system is returned to production (i.e. how long the equipment is out of production).

32. This includes notification time, diagnostic time, fix time, wait time (cool down), reassembly, alignment, calibration, test time, back to production, etc..
Mean time to repair ultimately reflects how well an organization can respond to a problem and repair it.

33. Expressed mathematically, it is the total maintenance time divided by the total number of maintenance actions over a specific period.
Over the lifetime of an asset, each failure will vary depending on the severity of the issue.
Some issues will require a simple parts swap, while others could take days to diagnose and repair.
Prediction of the number of hours that a system or component will be unavailable whilst undergoing maintenance is of vital importance in reliability and availability studies.
Mean time to repair yields a lot of information that can help reliability engineers make informed decisions such as repair or replace, hire, optimize maintenance schedules, 

34. Mean Waiting Time The mean waiting period for a actual repair to begin is known as mean waiting time. Maintenance Action Rate It is the number of maintenance action that can be carried out on an equipment per hour. µ = 1÷MTTR

35. 3. Maintainability , Availability:
It is can be defined as the probability that a system or a unit will be restored to specific working conditions within a given period, when maintenance action is taking place.
As per accordance with prescribed procedures and resources.
It includes minimum cost as well as accuracy.

36. 4.Availability
It is the ratio of the time at which equipment is available for the designated operations to the total time of operation and maintenance of the equipment.
Ratio of equipment uptime to downtime over a specified period of time.
Availability Classifications
Instantaneous (or Point) Availability
Average Uptime Availability (or Mean Availability)
Steady State Availability
Inherent Availability
Achieved Availability
Operational Availability

37. Instantaneous or Point Availability, A(t)
Instantaneous (or point) availability is the probability that a system (or component) will be operational (up and running) at a specific time, t.
This classification is typically used in the military, as it is sometimes necessary to estimate the availability of a system at a specific time of interest (e.g., when a certain mission is to happen).

38. Average Uptime Availability (or Mean Availability), 
The mean availability is the proportion of time during a mission or time period that the system is available for use. It represents the mean value of the instantaneous availability function over the period (0, T) and is given by:

39. Steady State Availability, A(∞) 
The steady state availability of the system is the limit of the availability function as time tends to infinity. Steady state availability is also called the long-run or asymptotic availability. A common equation for the steady state availability found in literature is:

40. Inherent Availability : It is the probability that a system or equipment will operate satisfactorily when used under a prescribed conditions 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 will operate satisfactorily when used under a prescribed conditions with any scheduled or preventive maintenance at any given time. Achieved Availability = MTBM/MTBM+M

41. Operational Availability : In industry, a certain downtime always take place due to supplies or administrative works etc., It is the probability that a system or equipment will operate satisfactorily when used under a prescribed conditions in an actual environment without any scheduled or preventive maintenance at any given time. Operational Availability= MTBM/MTBM+MDT

43. 4. Maintenance Organisation
It’s Classification are
DeCentralized Maintenance:
 This model is the most common.
Here, you have a self-standing facility management organization and structure for each of the major business groups:
The Central Plant, which handles major heating and cooling, electrical, and possibly the roads, grounds, and sidewalks;
A Central Facility Group, which handles classroom and office buildings, including electrical, HVAC, plumbing, and structures,
These individual groups often have separate capital programs, purchasing and supply systems, fleets, maintenance teams and contractors.
They typically enjoy higher customer satisfaction than do those in a centralized structure, as well as a better team attitude and ownership

44. Centralized :
The centralized organization brings all of the facility management and maintenance groups into one organization, so control of standards and procedures becomes consistent across the entire organization.
A centralized approach undoubtedly is more efficient, the quality of repairs and installations is higher, and more consistency exists in the approach to asset and equipment reliability.
The most common negative is typically a reduction in customer satisfaction. To address this challenge, the leadership team of the program and process must be very strong and have best-in-class performance measures in place so everyone can easily see even the most subtle changes in performance.

45. Partially Localized/ Cetnralized Planning: Suppose there five plants in an organization. For three plants they have central planning plant and for rest other two they have local planning. Such type of Maintenance Planning is known as Partially Centralized Maintenance Planning.

47. Two types of organization
Line organization is the most oldest and simplest method of administrative organization.
According to this type of organization, the authority flows from top to bottom in a concern.
The line of command is carried out from top to bottom. This is the reason for calling this organization as scalar organization which means scalar chain of command is a part and parcel of this type of administrative organization
. In this type of organization, the line of command flows on an even basis without any gaps in communication and co- ordination taking place.

48. Features of Line Organization
It is the most simplest form of organization.
Line of authority flows from top to bottom.
Specialized and supportive services do not take place in these organization.
Unified control by the line officers can be maintained since they can independently take decisions in their areas and spheres.
This kind of organization always helps in bringing efficiency in communication and bringing stability to a concern.

49. Merits of Line Organization
Simplest- It is the most simple and oldest method of administration.
Unity of Command- In these organizations, superior- subordinate relationship is maintained and scalar chain of command flows from top to bottom.
Better discipline- The control is unified and concentrates on one person and therefore, he can independently make decisions of his own. Unified control ensures better discipline. .

50. Fixed responsibility- In this type of organization, every line executive has got fixed authority, power and fixed responsibility attached to every authority.
Flexibility- There is a co-ordination between the top most authority and bottom line authority. Since the authority relationships are clear, line officials are independent and can flexibly take the decision. This flexibility gives satisfaction of line executives.
Prompt decision- Due to the factors of fixed responsibility and unity of command, the officials can take prompt decision

51. Over reliance- The line executive’s decisions are implemented to the bottom. This results in over-relying on the line officials.
Lack of specialization- A line organization flows in a scalar chain from top to bottom and there is no scope for specialized functions. For example, expert advices whatever decisions are taken by line managers are implemented in the same way.
Inadequate communication- The policies and strategies which are framed by the top authority are carried out in the same way. This leaves no scope for communication from the other end. The complaints and suggestions of lower authority are not communicated back to the top authority. So there is one way communication.

52. Lack of Co-ordination- Whatever decisions are taken by the line officials, in certain situations wrong decisions, are carried down and implemented in the same way. Therefore, the degree of effective co-ordination is less.
Authority leadership- The line officials have tendency to misuse their authority positions. This leads to autocratic leadership and monopoly in the concern.

53. Line and staff organization
Line and staff organization is a modification of line organization and it is more complex than line organization.
According to this administrative organization, specialized and supportive activities are attached to the line of command by appointing staff supervisors and staff specialists who are attached to the line authority.
The power of command always remains with the line executives and staff supervisors guide, advice and council the line executives. Personal Secretary to the Managing Director is a staff official.

54. It’s Benefits :
Relief to line of executives- In a line and staff organization, the advice and counseling which is provided to the line executives divides the work between the two. The line executive can concentrate on the execution of plans and they get relieved of dividing their attention to many areas.
Expert advice- The line and staff organization facilitates expert advice to the line executive at the time of need. The planning and investigation which is related to different matters can be done by the staff specialist and line officers can concentrate on execution of plans.
Benefit of Specialization- Line and staff through division of whole concern into two types of authority divides the enterprise into parts and functional areas. This way every officer or official can concentrate in its own area.

55. Better co-ordination- Line and staff organization through specialization is able to provide better decision making and concentration remains in few hands. This feature helps in bringing co- ordination in work as every official is concentrating in their own area.
Benefits of Research and Development- Through the advice of specialized staff, the line executives, the line executives get time to execute plans by taking productive decisions which are helpful for a concern. This gives a wide scope to the line executive to bring innovations and go for research work in those areas. This is possible due to the presence of staff specialists.
Training- Due to the presence of staff specialists and their expert advice serves as ground for training to line officials. Line executives can give due concentration to their decision making. This in itself is a training ground for them.

56. Balanced decisions- The factor of specialization which is achieved by line staff helps in bringing co-ordination. This relationship automatically ends up the line official to take better and balanced decision.
Unity of action- Unity of action is a result of unified control. Control and its effectivity take place when co-ordination is present in the concern. In the line and staff authority all the officials have got independence to make decisions. This serves as effective control in the whole enterprise

57. Organisation Structure of Maintenance Department
Maintenance Superintendent
Facilities Foreman
Foreman Shops Maintenance
Foreman Planning Maintenance
Foreman Engineering
Field Foreman
Engineering Assistant or Technician

58. Facilities Foreman
Air Conditioning
Water Supply
Steam
Power Required.
Shops Maintenance
Maintenance of Machines/Equiments
Repair
Lubrication

59. Foreman Planning and Maintenance
Work order system
Scheduling
Backlogs Control
Performance Reports
Field Foreman
Buildings
Yards
Fire Protection
Waste Disposal

60. 5. Maintenance Economics
Life Cycle Cost Analysis
The factors to be considered in the purchase of equipment for industries include the cost, quality, performance and maintenance requirements.
Life cycle costing is the cost analysis for the equipment over a span of time which includes the capital cost, operating cost and maintenance costs.
It leads to selection of proper and economically viable equipment.

61. Maintenance cost :
-difficult to measure due to random nature of failures.
-records on maintenance history can be used .
Component of Maintenance Cost :
Fixed cost and Variable cost :
Fixed includes the cost of support facilities, including the maintenance staff.
Variable cost includes the consumption of spare parts, components replacements etc.,

63. All buildings & capital assets go through a life cycle process during the course of their life.
In the asset life cycle class, there are three different phases identified based on studies.
Almost all the equipment, that operates under normal distribution curve (over 99.0%) goes through the following three phases. As per Six Sigma & Statistical studies, 95% of the universal processes go under normal distribution curve (bell curve).

64. You can take up any process like making a lemonade and selling on the street or buying a car, the experiences remain the same and all these activities fall under bell curve.
Studies from top universities in the world on plant maintenance have revealed that majority of the asset / equipment maintenance issues are caused due to dirt & dust, which is single most key constituent in the equipment break downs; followed by frictional issues & failure of materials.
But the mother of all maintenance failures is human error, which causes 80% of the breakdowns in any organization, for the equipment failure

65. Phase-1 "Start-Up Cycle": Failures occur on materials, workmanship, installation, and/or operator mis-handling on new equipment. Some of the costs are partially covered by equipment warranty. By the nature of this life cycle, there is a lack of historical data.
The failures are very hard to predict or plan for, and it is difficult to know which parts / components to be kept in stock (for back filling in case of failure)
 Preventative Maintenance Standards are developed in this cycle. This period could last from one day to several years on a complex system. Be vigilant in monitoring the mis-application (the wrong machine for the right job), inadequate engineering and manufacturer deficiencies.

66. Phase-2 "Wealth Cycle": This cycle is where the organization makes money on the useful output of the machine, building, or other asset. This cycle is also called the “usage cycle”.
Phase-3 "Breakdown Cycle": This is the cycle that organizations find themselves 'in', when they do not follow a good Preventative Maintenance (PM) practice. Phase-3 is characterized by wear out failures, breakdowns, corrosion failures, fatigue, downtime, and other general headaches

67. Parts usage change as we move more deeply into life cycle 3.
The parts tend to be more in number, bigger, more expensive, and harder to get.
The goal of most maintenance operations is to identify when an asset is slipping into this Phase-3 and fix the problems. Fixing the problem will result in the assets moving back to life cycle 2, which is getting back to Wealth Cycle mode.

68. End of unit 1