maintenance and repair

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Maintenance and Repair

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Page 1: Maintenance and Repair

Evaluation

Semester work

40%

Attendance 10%

Quiz 15%

Report 15%

Mid term Exam

30%

Final term Exam

30%

Page 2: Maintenance and Repair

1. Introduction . 2. Maintenance in our life. 3. What is Maintenance? 4. Maintenance history. 5. What are the maintenance

actions?

Page 3: Maintenance and Repair

6. Maintenance terms. 7. Maintenance Costs. 8. Maintenance Objectives Or role

of maintenance. 9. Types of Maintenance. 10.Maintenance Strategies.

Page 4: Maintenance and Repair

11.Computerized Maintenance System. 12.Structures of maintenance systems. 13.Diagnostic Technologies. 14.Maintenance Planning and Control. 15.Fundamental Requirements of

Effective Maintenance.

Page 5: Maintenance and Repair

1.Introduction Questions?

Why do we need maintenance? What are the costs of doing maintenance? What are the costs of not doing maintenance? What are the benefits of maintenance? How can maintenance increase profitability of

company?

Page 6: Maintenance and Repair

2. Maintenance in our life

• Hospital. • Restaurants. • Transport companies. • Banks. • Hotels and resorts. • Shopping malls. • Gas station.

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2. Maintenance in our life

• Electronic • Automotive • Petrochemicals • Refinery • Furniture • Ceramics • Food and beverages

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2. Maintenance in our life

Page 9: Maintenance and Repair

2. Maintenance in our life

Page 10: Maintenance and Repair

3. What is Maintenance?

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 equipments in working order.

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Page 11: Maintenance and Repair

3. What is Maintenance?

The combination of all technical and administrative

actions, including supervision actions, intended to

retain an item in, or restore it to, a state in which it

can perform a required function.

Maintenance is a set of organised activities that are

carried out in order to keep an item in its best

operational condition with minimum cost.

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Page 12: Maintenance and Repair

3. What is Maintenance?

• The maintenance department is one of the greatest levers of profitability that any capital intensive organization has.

• An average of 40 – 50% of a capital intensive industries operating budget is consumed by maintenance expenditure.

• With the advances today in technology affecting maintenance this figure can be greatly reduced. As such maintenance is often an organizations largest single controllable expense.

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Page 13: Maintenance and Repair

4. Maintenance History

1. In the period of pre-World War II, people thought of

maintenance as an added cost to the plant which did

not increase the value of finished product.

Therefore, the maintenance at that era was

restricted to fixing the unit when it breaks because

it was the cheapest alternative

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4. Maintenance History

2. During and after World War II at the time when the

advances of engineering and scientific technology

developed, people developed other types of

maintenance, which were much cheaper such as

preventive maintenance.

In addition, people in this era classified

maintenance as a function of the production system.

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4. Maintenance History

3. Nowadays, increased awareness of such issues as environment safety, quality of product and services makes maintenance one of the most important functions that contribute to the success of the industry.

World-class companies are in

continuous need of a very well organised

maintenance programme to compete world-wide.

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4. Maintenance History

Fix the equipment

when it breaks

-Term terotechnology

introduced.

-Recognition of need to

present equipment

failures.

-Models for preventive

maintenance developed.

-Increased awareness

of:

-Environment

-Safety

-Quality

-Need for reliable

equipment.

-Reduction in costs.

Pre-World War II Post-World War II 1980 Onwards

Time

De

ve

lop

me

nt

of

Ma

inte

nan

ce

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5. What are the maintenance actions?

Actions of maintenance function could be either

1. Check or inspection : not only means checking the part, but also

checking machine performance that affects part quality and

machine productivity.

2. Minor repair: minor repair means a repair other than a major repair.

Ex: means maintenance, repair or replacement of the alternator,

generator, starter, water pump, battery.

3. Major repair: means any maintenance, repair or replacement not

listed in the definition of “minor repair”

Ex: subsection, the removal of engines, rebuilding of engines.

4. Overhaul: the act of improving by renewing and repairing.

5. Replacement: changing failure parts by new parts.

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6. Maintenance Terms Maintenance: The combination of all technical and associated actions by which an equipment or a system is kept or restored to a state in which it can perform its functions. Maintenance history of an item: A history record showing repair, spares, etc. used to assist maintenance planning.

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6. Maintenance Terms

Maintenance schedule: A comprehensive list of items and the maintenance tasks required, including the intervals at which maintenance should be performed.

Planned maintenance: The maintenance organized and carried out with forethought, control, and the use of records to meet a predetermined plan.

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6. Maintenance Terms

Availability: The ability of an equipment to successfully

perform its required function at a stated instant of time or over a stated period of time.

Breakdown: Failure resulting in the non-availability of an

equipment.

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Page 21: Maintenance and Repair

6. Maintenance Terms

Condition-based maintenance: The preventive maintenance initiated as a result of

knowledge of the condition of an equipment observed through routine or continuous monitoring.

Condition monitoring: The continuous or periodic measurement and

interpretation of data to infer the condition of an equipment to determine its need for maintenance.

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6. Maintenance Terms

Corrective maintenance: The maintenance carried out after a failure has

occurred and intended to restore an equipment to a state in which it can perform its required function.

Emergency maintenance: That maintenance which is necessary in order to

avoid serious consequences, such as loss of production time and unsafe conditions .

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6. Maintenance Terms Failure: a. The termination of the ability of an equipment to perform

its required function. b. Failure – inability to produce work in appropriate manner

Examples 1. Equipment / machine failure on production floor –

worn out bearing, pump, pressure leaks, broken shaft, overheated machine etc.

2. Equipment failure in office – failure of power supply, air-conditioned system, computer network, photocopy machine .

3. Vehicle failure – brake, transmission, engine, cooling system.

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6. Maintenance Terms

Fault: An unexpected deviation from requirements which require corrective action.

Feedback: A report on the success or failure of an action to achieve its desired objectives and which can be used to improve a process.

Forced outage: Outage due to the unscheduled stopping of equipment.

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6. Maintenance Terms

Inspection:

The process of measuring, examining, testing, gauging or otherwise detecting any deviations from specifications.

Maintainability:

The ability of an equipment, under stated conditions of use, to be retained in, or restored to, a state in which it can perform its required function, when maintenance is performed under stated conditions and using prescribed procedures and resources .

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6. Maintenance Terms Overhaul:

A comprehensive examination and restoration of an equipment, or a major part, to an acceptable condition.

Preventive maintenance:

The maintenance carried out at predetermined intervals or intended to minimize the probability of failure or the performance degradation of equipment.

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6. Maintenance Terms

Repair: To restore an item to an acceptable condition by the renewal, replacement or replacement of damaged or worn parts.

Running maintenance: Maintenance which can be carried out whilst the equipment is in service.

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6. Maintenance Terms

Shut down maintenance: Maintenance which can only be carried out when the equipment is out of service.

Spare stock: Items which are available for maintenance purposes or for the replacement of defective parts.

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6. Maintenance Terms

Work specification (order): A document describing the way in which the work is to be carried out. It may define the materials, tools, time standards, and procedures.

Reliability

is the probability that a machine will function properly for a specified time.

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ReliabilityReliability

Reliability of the process isReliability of the process is

RRss = R= R11 x Rx R22 x Rx R33 x … x x … x RRnn

wherewhere RR11 = reliability of component = reliability of component 11

RR22 = reliability of component = reliability of component 22

and so on.and so on.

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RRss

RR33

.99

RR22

.80

Reliability ExampleReliability Example

RR11

.90

Reliability of the process isReliability of the process is

RRss = R= R11 x Rx R22 x Rx R33 = .= .90 90 x .x .80 80 x .x .99 99 = .= .713 713 or or 7171..33%%

Page 32: Maintenance and Repair

7. Maintenance Costs

1. Direct costs – Cost of Periodic Inspection. – Service Cost. – Repair Cost, Overhaul Cost.

2. Stand-by costs – Cost of Operating and Maintaining a Standby

Unit.

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7. Maintenance Costs

3. Lost production costs : – Cost due to Equipment down time.

4. Degradation cost – Cost occurring due to deterioration of the life

span of equipment due to no maintenance or inadequate maintenance.

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8. ROLE OF MAINTENANCE ORGANIZATION

Too many maintenance organizations continue to pride themselves on how fast they can react to a catastrophic failure or production interruption rather than on their ability to prevent these interruptions.

While few will admit their continued adherence to this breakdown mentality, most plants continue to operate in this mode.

Contrary to popular belief, the role of the maintenance organization is to maintain plant equipment, not to repair it after a failure.

The mission of maintenance in a world-class organization is to achieve and sustain optimum availability.

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8. ROLE OF MAINTENANCE ORGANIZATION

The role of the maintenance organization is to maintain plant equipment in: 1. Optimum Availability. 2. Optimum Operating Condition. 3. Maximum Utilization of Maintenance Resources. 4. Optimum Equipment Life. 5. Minimum Spares Inventory. 6. Ability to React Quickly.

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8. ROLE OF MAINTENANCE ORGANIZATION

1. Optimum Availability

The production capacity of a plant is, in part, determined by the availability of production systems and their auxiliary equipment.

The primary function of the maintenance organization is to ensure that all machinery, equipment, and systems within the plant are always on line and in good operating condition.

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8. ROLE OF MAINTENANCE ORGANIZATION

2. Optimum Operating Condition • The maintenance organization has the

responsibility to maintain all direct and indirect manufacturing machinery, equipment, and systems so that they will be continuously in optimum operating condition.

• Minor problems, no matter how slight, can result in poor product quality, reduce production speeds, or affect other factors that limit overall plant performance.

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8. ROLE OF MAINTENANCE ORGANIZATION

3. Maximum Utilization of Maintenance Resources • The maintenance organization controls a

substantial part of the total operating budget in most plants.

• In addition to an appreciable percentage of the total plant labor budget, the maintenance manager, in many cases, controls the spare parts inventory, authorizes the use of outside contract labor, and requisitions millions of dollars in repair parts or replacement equipment.

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8. ROLE OF MAINTENANCE ORGANIZATION

4. Optimum Equipment Life

• One way to reduce maintenance cost is to extend the useful life of plant equipment.

• The maintenance organization should implement programs that will increase the useful life of all plant assets.

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8. ROLE OF MAINTENANCE ORGANIZATION

5. Minimum Spares Inventory • Reductions in spares inventory should be a major

objective of the maintenance organization. • However, the reduction cannot impair their ability

to meet goals1 through 4. • With the predictive maintenance technologies that

are available today, maintenance can anticipate the need for specific equipment or parts far enough in advance to purchase them on an as-needed basis.

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8. ROLE OF MAINTENANCE ORGANIZATION

6. Ability to React Quickly

• Not all catastrophic failures can be avoided. Therefore the maintenance organization must maintain the ability to react quickly to the unexpected failure.

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9. Types of Maintenance

UNPLANNED

MAINTENANCE

(REACTIVE)

REMEDIAL DEFERRED CONDITION -

BASED

STATISTICAL

- BASED

ROUTINE RUNNING

DESIGN - OUT ENGINEERING

SERVICES

WINDOW

MAINTENANCE

BREAKDOWN

EMERGENCY

PLANNED

MAINTENANCE

(PROACTIVE)

CORRECTIVE

MAINTENANCE

PREDECTIVE

MAINTENANCE

PREVENTIVE

MAINTENANCE

IMPROVEMENT

MAINTENANCE

SHUTDOWN

CORRECTIVE

SHUTDOWN

PREVENTIVE

SHUTDOWN

IMPROVEMENT

Shutdown Maintenance

OPPORTU-

NITY

Page 43: Maintenance and Repair

9. Main Types of Maintenance

a) Run To Failure Maintenance (RTF)

or Unplanned Maintenance

b) Preventive Maintenance (PM)

c) Corrective Maintenance (CM)

d) Improvement Maintenance (IM)

e) Predictive Maintenance (PDM)

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a) Run to Failure Maintenance (RTF)

It is the oldest type of maintenance.

The required repair, replacement, or restore

action performed on a machine or a facility after

the occurrence of a failure in order to bring this

machine or facility to at least its minimum

acceptable condition.

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a) Run to Failure Maintenance (RTF)

It is subdivided into two types:

1. Emergency maintenance: it is carried out as fast

as possible in order to bring a failed machine or

facility to a safe and operationally efficient

condition.

2. Breakdown maintenance: it is performed after

the occurrence of an advanced considered failure

for which advanced maintenance has been made

in the form of repair method, spares, materials,

labour and equipment.

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a) Run to Failure Maintenance (RTF)

Disadvantages:

1. Its activities are expensive in terms of both direct

and indirect cost.

2. Using this type of maintenance, the occurrence of

a failure in a component can cause failures in

other components in the same equipment, which

leads to low production availability.

3. Its activities are very difficult to plan and

schedule in advance.

Page 47: Maintenance and Repair

a) Run to Failure Maintenance (RTF)

This type of maintenance is useful in the following situations:

1. If the failure of a component in a system is unpredictable.

2. If the cost of performing run to failure maintenance activities is lower than performing other activities of other types of maintenance.

3. If the equipment failure priority is too low in order to include the activities of preventing it within the planned maintenance budget.

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b) Preventive Maintenance (PM)

It is a set of activities that are performed on plant

equipment, machinery, and systems before the

occurrence of a failure in order to protect them and

to prevent or eliminate any degradation in their

operating conditions.

The advantages of applying preventive

maintenance activities are to satisfy most of

maintenance objectives.

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b) Preventive Maintenance (PM)

The factors that affect the efficiency of this type of

maintenance:

i. The need for an adequate number of staff in the maintenance department in order to perform this type of maintenance.

ii. The right choice of production equipment and machinery that is suitable for the working environment and that can tolerate the workload of this environment.

iii. The required staff qualifications and skills, which can be gained through training.

iv. The support and commitment from executive management to the PM programme.

v. The proper planning, scheduling and applying of PM programme.

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b) Preventive Maintenance (PM)

It is good for those machines and facilities which their failure would cause serious production losses.

Its aim is to maintain machines and facilities in such a condition that breakdowns and emergency repairs are minimised.

Its activities include replacements, adjustments, major overhauls, inspections and lubrications.

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b) Preventive Maintenance (PM)

Researchers subdivided preventive maintenance into different kinds according to the nature of its activities:

1. Routine maintenance which includes those maintenance activities that are repetitive and periodic in nature such as lubrication, cleaning, and small adjustment.

2. Running maintenance which includes those maintenance activities that are carried out while the machine or equipment is running and they represent those activities that are performed before the actual preventive maintenance activities take place.

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b) Preventive Maintenance (PM)

3. Opportunity maintenance which is a set of maintenance activities that are performed on a machine or a facility when an unplanned opportunity exists during the period of performing planned maintenance activities to other machines or facilities.

4. Window maintenance which is a set of activities that are carried out when a machine or equipment is not required for a definite period of time.

5. Shutdown preventive maintenance which is a set of preventive maintenance activities that are carried out when the production line is in total stoppage situation.

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c) Corrective Maintenance (CM)

In this type, actions such as repair,

replacement, or restore will be carried out

after the occurrence of a failure in order to

eliminate the source of this failure or

reduce the frequency of its occurrence.

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c) Corrective Maintenance (CM)

This type of maintenance is subdivided into three types:

1. Remedial maintenance, which is a set of activities that

are performed to eliminate the source of failure without

interrupting the continuity of the production process.

The way to carry out this type of corrective maintenance

is by taking the item to be corrected out of the

production line and replacing it with reconditioned item

or transferring its workload to its redundancy.

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c) Corrective Maintenance (CM)

2. Deferred maintenance, which is a set of

corrective maintenance activities that are not

immediately initiated after the occurrence of a

failure but are delayed in such a way that will not

affect the production process.

3. Shutdown corrective maintenance, which is a

set of corrective maintenance activities that are

performed when the production line is in total

stoppage situation.

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c) Corrective Maintenance (CM)

The main objectives of corrective maintenance are the maximisation of the effectiveness of all critical plant systems, the elimination of breakdowns, the elimination of unnecessary repair, and the reduction of the deviations from optimum operating conditions.

The difference between corrective maintenance and preventive maintenance is that for the corrective maintenance, the failure should occur before any corrective action is taken.

Corrective maintenance is different from run to failure maintenance in that its activities are planned and regularly taken out to keep plant’s machines and equipment in optimum operating condition.

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c) Corrective Maintenance (CM)

The way to perform corrective maintenance

activities is by conducting four important steps:

1. Fault detection.

2. Fault isolation.

3. Fault elimination.

4. Verification of fault elimination.

In the fault elimination step (3) several actions could be

taken such as adjusting, aligning, calibrating, reworking,

removing, replacing or renovation.

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c) Corrective Maintenance (CM)

Corrective maintenance has several prerequisites in

order to be carried out effectively:

1. Accurate identification of incipient problems.

2. Effective planning which depends on the skills of the

planners, the availability of well developed maintenance

database about standard time to repair, a complete repair

procedures, and the required labour skills, specific tools,

parts and equipment.

3. Proper repair procedures.

4. Adequate time to repair.

5. Verification of repair.

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d) Improvement Maintenance (IM)

It aims to reduce or eliminate the need for maintenance.

This type of maintenance is subdivided into three types as follows:

1. Design-out maintenance which is a set of activities

that are used to eliminate the cause of maintenance, simplify maintenance tasks, or raise machine performance from the maintenance point of view by redesigning those machines and facilities which are vulnerable to frequent occurrence of failure and their long term repair or replacement cost is very expensive.

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Page 60: Maintenance and Repair

d) Improvement Maintenance (IM)

2. Engineering services which includes construction

and construction modification, removal and installation, and rearrangement of facilities.

3. Shutdown improvement maintenance which is a

set of improvement maintenance activities that are performed while the production line is in a complete stoppage situation.

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e)Predictive Maintenance (PDM)

Predictive maintenance is a set of activities that

detect changes in the physical condition of

equipment (signs of failure) in order to carry out

the appropriate maintenance work.

Some researchers classified predictive

maintenance as a type of preventive maintenance.

It is classified into two kinds according to the

methods of detecting the signs of failure:

– Condition-based predictive maintenance.

– Statistical-based predictive maintenance.

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e)Predictive Maintenance (PDM)

Condition-based predictive maintenance depends

on continuous or periodic condition monitoring

equipment to detect the signs of failure.

Statistical-based predictive maintenance depends

on statistical data from the recording of the

stoppages of the in-plant items and components

in order to develop models for predicting

failures.

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Note that Failure cause disruption, waste, accident,

inconvenience and expensive. Operators less able to do repairs themselves. Machine and product failure can have effect

on company’s operation and profitability. Breakdown causes losses . Maintenance, reliability, product quality,

productivity, safety and supply chain are related.

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10. Maintenance Strategies (policies)

1. Breakdown Maintenance (Run To Failure). 2. Fault Finding (FF). 3. Time directed Preventive Maintenance(TD). 4. Condition Based Maintenance (CBD). 5. Design Modification (DM). 6. Replacement Instead of Maintenance (RIM). 7. Planned Replacement (PR). 8. Opportunity Maintenance (OM).

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11.Computerized Maintenance System

Output Reports

Inventory and purchasing reports

Equipment parts list

Equipment history reports

Cost analysis (Actual vs. standard)

Work orders

– Preventive maintenance

– Scheduled downtime

– Emergency maintenance

Data entry – Work requests – Purchase

requests – Time reporting – Contract work

Data FilesData Files

Personnel data with skills, wages, etc.

Equipment file with parts list

Maintenance and work order

schedule

Inventory of spare parts

Repair history file

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12.Structures of maintenance systems

One of the first considerations in planning a maintenance organization is to decide whether it is advantageous to have a centralized or decentralized maintenance function.

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12. Structures of maintenance systems

The structures of maintenance system may belong to one of the following three structures: 1. Centralized maintenance system. 2. Decentralized maintenance system. 3. Combined centralized – decentralized

maintenance system.

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12. Structures of maintenance systems

1. Centralized maintenance system

Generally, centralized maintenance serves well in small- and medium-sized enterprises housed in one structure, or service buildings located in an immediate geographic area. The centralized maintenance is suitable for

ensuring large repair actions, overhauls, unique spare parts manufacturing etc.

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12. Structures of maintenance systems

1. Centralized maintenance system Advantages One source of information advises the Board of Directors. Optimization and better monitoring of contracted work. Better supervision and optimization of maintenance cost. Possibility of reducing down time for yearly overhauls. More efficient compared to decentralized maintenance. Fewer maintenance personnel required. Greater use of special equipment and specialized maintenance persons.

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12. Structures of maintenance systems

1. Centralized maintenance system Disadvantages Smaller availability and flexibility in the case of

small repairs. Disunion between operators and maintenance

workers working on machines. Requires more time getting to and from the work

area or job

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12. Structures of maintenance systems 1. Centralized maintenance system

Disadvantages No one individual becomes totally familiar with

complex hardware or equipment. More difficult supervision because of remoteness of

maintenance site from the centralized headquarters Higher transportation cost due to remote

maintenance work

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12. Structures of maintenance systems

2. Decentralized maintenance system In the case of decentralized maintenance a

maintenance group is assigned to a particular area or unit.

The decentralized maintenance is useful for servicing, lubrication, small operating repairs.

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12. Structures of maintenance systems

2. Decentralized maintenance system Advantages Good availability and flexibility from point of view

of operating repairs. Better cohesion between operators and

maintenance workers working on machines. Maintenance is fully subordinated to production

requirements. Reduced travel time to and from maintenance jobs.

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12. Structures of maintenance systems

2. Decentralized maintenance system Disadvantages Maintenance is not managed directly by top

management. Lower quality, non-performance in optimal

maintenance time. Decentralization of information.

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12. Structures of maintenance systems

3. Combined centralized – decentralized maintenance system

Past experience indicates that in large plants a combination of centralized and decentralized maintenance normally works best. The main reason is that the benefits of both the systems can be achieved with essentially a low number of drawbacks.

No one particular type of maintenance organization is useful for all types of enterprises.

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12. Structures of maintenance systems

3. Combined centralized – decentralized maintenance system

It takes over the advantages of centralized and

decentralized maintenance organization. It reduces disadvantages of centralized and

decentralized maintenance organization.

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12. Structures of maintenance systems

Maintenance personnel Maintenance personnel are: 1. Craftsman: lubricate machinery, change parts, or

perform other routine machinery maintenance. 2. Foreman: responsible for supervision of

all maintenance staff on a daily basis and the quality control of all work.

3. Maintenance planner: responsible for planning, scheduling and organizing the efficient operation and performance or work

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12. Structures of maintenance systems

Maintenance personnel Maintenance personnel are: 4. Maintenance Engineer : maintenance engineers

plan the routine maintenance of equipment and machinery. They work on-site or remotely diagnose faults

5. Maintenance Manger : handling the maintenance of a company, facility or location.

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13. Diagnostic Technologies

The most commonly applied condition

based maintenance techniques are:

1. Vibration analysis,

2. Oil analysis,

3. Thermography,

4. Ultrasonics,

5. Penetrants.

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1. Vibration analysis

Vibration can be defined as the movement of a mass from its point of rest through all positions back to the point of rest, where it is ready to repeat the cycle.

The time it takes to do this is its period, and

the number of repetitions of this cycle in a given time is its frequency.

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1. Vibration analysis

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1. Vibration analysis

The severity of vibration is determined by the amplitude - or maximum movement - its peak velocity and peak acceleration.

Vibration analysis in condition monitoring,

is accomplished by comparing vibration characteristics of current operation to a baseline, measured when the machinery was known to be operating normally.

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1. Vibration analysis

Vibration analysis techniques can be used to monitor the performance of mechanical equipment that rotates, reciprocates or has other dynamic actions. Examples include gearboxes, roller bearings,

motors, pumps, fans, turbines, belt or chain drives, compressors, generators, conveyors and reciprocating engines.

Page 84: Maintenance and Repair

2.Oil analysis

Ferrography and magnetic chip detection examine the iron-based wear particles in lubrication oils to determine the type and extent of wear, and can help determine the specific component that is wearing.

Spectrometric oil analysis measures the presence

and amounts of contaminants in the oil through atomic emission or absorption spectrometry.

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2.Oil analysis

Spectrometric Magnetic chip

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2.Oil analysis It is useful for determining not only iron, but also

other metallic and not metallic elements, which can be related to the composition of the various machine components, like bearings, bushings, piston rings, etc.

It is useful when wear particles are initially being generated in the early stages of failure, as they are small.

Chromatography measures the changes in lubricant properties, including viscosity, flash point, water content and insoluble, through selective absorption and analysis.

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3.Thermography Thermography measures the surface

temperature through the measurement of infra-red radiation. The most common uses for thermography are

for determining poor electrical connections and hot spots, furnace and kiln refractory wear and critical boiler and turbine component overheating. An infra-red camera shows surface temperature

variations, calibrated to provide the absolute temperature or temperature gradients through black and white or color variations.

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3.Thermography

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4.Ultrasonic There are several techniques for ultrasonic

testing, but they all are used to determine faults in welds, coatings, piping, tubes, structures, shafts, etc.

Cracks, gaps, corrosion and inclusions are

discovered by transmitting ultrasonic pulses or waves through the material and assessing the resultant signature to determine the location and severity of the discontinuity.

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4.Ultrasonic

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5. Penetrants

Electrostatic and liquid dye penetrants are used to detect cracks and discontinuities on surfaces, caused in manufacturing, by wear, fatigue, maintenance and overhaul procedures and corrosion. The penetrant is applied and allowed to

penetrate into the anomalies. The surface is cleaned and the penetrant revealed through direct visual, fluorescent or electrostatic techniques.

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5. Penetrants

1. Section of material with a surface-breaking crack that is not visible to the naked eye.

2. Penetrant is applied to the surface.

3. Excess penetrant is removed.

4. Developer is applied, rendering the crack visible.

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14.Maintenance Planning

and Control

1. Planning 2. Maintenance control 3. Characteristic of an Effective Operation and

Control System(OCS) 4. Vehicles for Planning and control 5. Purpose of maintenance work order system 6. Information carried by a work order

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1. PLANNING

Planning is an analytical process which

encompasses an assessment of future, the

determination of desired objectives, the

development of a course of action to achieve such

objectives and the selection of a course of action

among alternatives.

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2. Maintenance Control

An effective maintenance operation and control system is the backbone for sound maintenance management.

Controlling maintenance means the

coordination of demand for maintenance and available resources to achieve a desired level of effectiveness and efficiency.

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3. Characteristic of an Effective Operation and Control System(OCS)

The following five items must have clear methods and procedures of handling in any effective OCS . 1. Maintenance Demand ( What work to be

done and when).

2. Maintenance resources ( who will do the work and what material and tools needed).

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3. Characteristic of an Effective Operation and Control System(OCS)

3. Procedures means for coordinating, scheduling and executing the work.

4. Performance and quality standards ( how

long it takes to do a job and acceptable specification).

5. Feedback monitoring and control.

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4. Vehicles for Planning and control

The work order system : is the vehicle for planning and controlling maintenance work. It also provides the needed information for monitoring and reporting maintenance work. A clear goal and effective procedures are essential for the implementation of the work order system and control of maintenance activities

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5. PURPOSE OF MAINTENANCE WORK ORDER SYSTEM

1. Requesting in writing the work to be performed. 2. Assigning the Best Method and Safety to Perform

work in an estimated amount of time. 3. Reducing Cost through Man-Hours and

Material Control.

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5. PURPOSE OF MAINTENANCE WORK ORDER SYSTEM

4. Performing Predictive and Preventive Maintenance. 5. Improving Planning & Scheduling of Maintenance

work. 6. A source of Data Collection for Reporting Time

Standard Development and Control.

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6. INFORMATION CARRIED BY A WORK ORDER

Planning Information 1. Inventory Number Unit Description 2. Person Requesting Job 3. Job Description 4. Time Standards 5. Job Specification and Code Number

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6. INFORMATION CARRIED BY A WORK ORDER

Planning Information 6 Date Required and Priority 7 Trades Required and Co-ordinating Foreman 8 Special Tools 9 Safety Procedures 10 Drawing and Manual Number

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6. INFORMATION CARRIED BY A WORK ORDER

Control Information 1. Cost Code for Work Type. 2. Actual Time Taken. 3. Cause and Consequence of Failure. 4. Action Taken.

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15.Fundamental Requirements of Effective Maintenance

Effective maintenance is not magic, nor is it

dependent on exotic technologies or expensive instruments or systems.

Instead, it is dependent on doing simple, basic tasks that will result in reliable plant systems.

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15.Fundamental Requirements of Effective Maintenance

These basics include the following: 1. Inspections 2. Human Senses 3. Sensors 4. Thresholds 5. Lubrication 6. Calibration

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15. Fundamental Requirements of Effective Maintenance

1. Inspections • Careful inspection, which can be done without ‘‘tearing

down’’ the machine, saves both technician time and exposure of the equipment to possible damage.

• For example, piston rings in an engine or compressor cylinder quickly wear to the cylinder wall configuration. If they are removed for inspection, the chances are that they will not easily fit back into the same pattern. As a result, additional wear will occur and the rings will have to be replaced much sooner than if they were left intact and performance-tested for pressure produced and metal particles in the lubricating oil.

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15.Fundamental Requirements of Effective Maintenance

2. Human Senses

• Humans have a great capability for sensing unusual sights, sounds, smells, tastes, vibrations, and touches. Every maintenance manager should make a concerted effort to increase the sensitivity of his own and that of his personnel’s human senses.

• Experience is generally the best teacher.

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15.Fundamental Requirements of Effective Maintenance

3. Sensors • Since humans are not continually alert or sensitive to

small changes and cannot get inside small spaces, especially when machines are operating, it is necessary to use sensors that will measure conditions and transmit information to external indicators.

• Sensor technology is progressing rapidly; there have been considerable improvements in capability, accuracy, size, and cost.

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15.Fundamental Requirements of Effective Maintenance

3. Sensors • Pressure transducers, temperature thermocouples,

electrical ammeters, revolution counters, accelerometers, velocity seismic transducers, spectrometric oil analysis and a liquid height level float are examples found in most automobiles.

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15.Fundamental Requirements of Effective Maintenance

4. Thresholds • Now that instrumentation is becoming available to

measure equipment performance, it is still necessary to determine when that performance is ‘‘go’’ and when it is ‘‘no go.’’

• A human must establish the threshold point, which can then be controlled by manual, semi-automatic, or automatic means.

• The earlier the threshold is set and effective preventive maintenance done, the greater is the assurance that it will be done prior to failure.

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15.Fundamental Requirements of Effective Maintenance

5. Lubrication • The friction of two materials moving relative to each other

causes heat and wear. • Friction-related problems cost industries over $1 billion

per annum. Technology intended to improve wear resistance of metal, plastics, and other surfaces in motion has greatly improved over recent years, but planning, scheduling, and control of the lubricating program is often reminiscent of a plant handyman wandering around with his long-spouted oil can.

• Anything that is introduced onto or between moving surfaces to reduce friction is called a lubricant.

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15.Fundamental Requirements of Effective Maintenance

5. Lubrication • The functions of a lubricant are to: 1. Separate moving materials from each other to

prevent wear, scoring, and seizure 2. Reduce heat 3. Keep out contaminants 4. Protect against corrosion 5. Wash away worn materials.

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15.Fundamental Requirements of Effective Maintenance

6. Calibration • Calibration is a special form of preventive maintenance

whose objective is to keep measurement and control instruments within specified limits.

• A ‘‘standard’’ must be used to calibrate the equipment. Standards are derived from parameters established by the National Bureau of Standards (NBS).

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15.Fundamental Requirements of Effective Maintenance

6. Calibration • Secondary standards that have been manufactured to close

tolerances and set against the primary standard are available through many test and calibration laboratories and often in industrial and university tool rooms and research labs.

• Ohmmeters are examples of equipment that should be calibrated at least once a year and before further use if subjected to sudden shock or stress.