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Farid Keyhani, Master of Engineering, April 2009, E.mail: [email protected]

Implementing Total Productive Maintenance andComputation the Cost

MAINTENANCE AND RELIABILITY MANAGEMENT

2009

FARID KEYHANI

E-Mail: [email protected]

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Table of ContentsChapter 1 Introduction ................................................................................................ 4

Project Background ................................................................................................... 4Problems of the Current System ................................................................................. 5Aims and Objectives .................................................................................................. 6

System maintenance (especially in mechanized model) if well designed andimplemented to answer the practical affairs of conditions is to reduce maintenancecosts. In this paper we have introduced different methods, their history and their maintenance - computational methods, chart maintenance costs and the use of methods such as work tables, etc. to reduce the costs. ............................................... 6

Chapter 2 - Research Work ............................................................................................ 7Types of maintenance- introduction .......................................................................... 7

Breakdown Maintenance (BM) [9] , [5] ................................................................. 7Preventive maintenance [9] , [5] ............................................................................ 7Predictive maintenance [9], [5] .............................................................................. 8Condition-Based maintenance (CBM) ................................................................... 8

From PM to TPM ....................................................................................................... 9Total Productive Maintenance (TPM) ..................................................................... 10Different Generation of Maintenance ....................................................................... 11

Why TPM? [11] .................................................................................................. 11Six losses in the work place / decrease in plant cost: [9] ......................................... 125S The Foundation of TPM ................................................................................... 13Growing Expectations of Maintenance ................................................................... 13

Firs preventive maintenance ..................................................................................... 13Value of Preventive Maintenance ........................................................................ 13

Second predictive maintenance ............................................................................... 21React, plan or predict? .......................................................................................... 22Condition prediction ............................................................................................. 23Predict to protect profit ........................................................................................ 24Detect, diagnose, Act ........................................................................................... 24

Predictive Maintenance - Cost Effect ...................................................................... 25Planning aid to predictive maintenance [2] ....................................................... 25

How can escape of too much PM and how can release of plant cost? ................... 27The No. 1 Law You Should Know [6] ................................................................. 27Reducing Maintenance Cost in a Tough Economic Climate [8] .......................... 31

Chapter 3 ...................................................................................................................... 32In Conclusion [3], [1] ............................................................................................... 32

Chapter 4 ..................................................................................................................... 34References ................................................................................................................ 34

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Acronyms used in the report

KLIA An Airport in Malaysia, kuala lampur city

BM Breakdown Maintenance

CBM Condition-Based maintenanceTPM Total Productive Maintenance

5S Shine Straighten Systemize Sustain - Sort

RCFA Root Cause Failure Analyses

PLC Programmable Logic Controller

SCADA SCADA Soft were

PDM Predictive Maintenance System

JIT JUST-IN-TIME

TQM Total Quality Maintenance

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Chapter 1 Introduction

Project Background

.Today, developing countries in particular nations of South East Asia For

Economic and Industrial Development, and also the technologically developed

countries throughout the world are faced with the ever increasing costs of production,

maintenance and management. Therefore, they have the responsibility to ensure thatthey control these costs otherwise runaway costs that are not properly controlled will

ultimately plunge the firm into failure. Among the items forming the cost of goods

sold that need proper monitoring and controlling are direct materials; direct labor and

overhead costs. The area of interest can be about overhead costs of production that

have to be separately analyzed and solutions to the firms problems to be done

through appropriate action so that they reduce the costs of production and

maintenance. The most important items forming production cost of indirect materialsare depreciation; maintenance; repairs; electricity and fuel, etc. In order to promote

efficiency in the firm to help enhance its productivity, data analysis of all the data is

also necessary to be implemented and it can also be part of the costs .

The costs of machines and equipment during recent years have been increasing . And

most of the time, discussion about maintenance has been one of the most important

problems managers in industries have been facing and efforts have been made in this

regard to access ways to enhance profitability and increasing efficiency, safety and

decreasing the expenses. By implementing effective controlling programs and with

proper, regular surveillance of the status of equipment and information systems, the

management can decrease direct costs and indirect costs at the industries. In fact by

forecasting using an advanced system, they can find out the approximate time of

breakdown and this can reduce repair costs and reduce interruption-time at the

operating machinery can encourage effective planning for the desirable performance

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of the machines and it can also increase the safety , financial savings and overall, it

can increase economic performance.

Problems of the Current System

Research results in the United States of America shows that between 1979 and 2005,

the maintenance costs had an average growth of between 10% to 15% . The

technology development process and changes to technology in machinery

industries .Predictable growth in maintenance costs and repairs will continue with

greater acceleration

But more interesting results of this research are related to cost analysis. A very

surprising analysis shows that about 35% of the costs are unnecessary costs

and wasted expenses. It can be seen that the remainder that is 65%, actually

consists of the costs that are necessary.

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Aims and Objectives

System maintenance (especially in mechanized model) if well designed and

implemented to answer the practical affairs of conditions is to reduce

maintenance costs. In this paper we have introduced different methods,

their history and their maintenance - computational methods, chart

maintenance costs and the use of methods such as work tables, etc. to

reduce the costs.

.

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Chapter 2 - Research Work

Types of maintenance- introduction

Breakdown Maintenance (BM) [9] , [5]Breakdown maintenance is also called as run-to-failure maintenance. It may

be described as a fire-fighting approach to maintenance. Equipment is allowed to run

until failure. Then the failed equipment is repaired or replaced. In these strategies the

maintenance activities are not planned. These strategies are mostly used where the

consequences of failure do not result in significant expenditure. This is the oldest type

of maintenance. It is suitable for small, non-critical, low price equipments. Corrective

maintenance involves running systems to breakdown and can only be applied to

equipment which is inexpensive, largely duplicated and easy to repair or replace and

where loss of the machine or equipment for a particular process or job will not

constitute a significant disruption to production

Preventive maintenance [9] , [5]Preventive maintenance is a schedule of planned maintenance actions aimed at

the prevention of breakdowns and failures. The primary goal of preventive

maintenance is to prevent the failure of equipment before it actually occurs. It is

designed to preserve and enhance equipment reliability by replacing worn

components before they actually fail. Preventive maintenance activities include

equipment checks, partial or complete overhauls at specified periods, oil changes,

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lubrication and so on. In addition, workers can record equipment deterioration so they

know to replace or repair worn parts before they cause system failure. Recent

technological advances in tools for inspection and diagnosis have enabled even more

accurate and effective equipment maintenance. The ideal preventive maintenance

program would prevent all equipment failure before it occurs.

Predictive maintenance [9] , [5]A sound description of predictive maintenance is the application of

technologies and early detection processes to monitor and detect changes in condition

to allow more precise intervention. Predictive maintenance can be defined as follows:

measurements that detect the onset of a degradation mechanism, thereby allowing

casual stressors to be eliminated or controlled prior to any significant deterioration inthe component physical state Under predictive maintenance, diagnostic equipment is

used to measure the physical condition of equipment and it may include vibration

analysis, shock pulse methods, ultrasonic, thermo graphic analysis, oil analysis,

electrical surge comparisons, coolant analysis, wear particle analysis, and

performance trending.

All machines give early warning signs predicting their impending failure.

When one of these indicators reaches a specified level, work is undertaken to restore

the equipment to proper condition. This means that equipment is taken out of service

only when direct evidence exists that deterioration has taken place.

Condition-Based maintenance (CBM)Condition-based maintenance (CBM) includes scheduled maintenance as well

as corrective maintenance. CBM is not a technology or a technique, but it depends on

other technologies to provide this objective evidence. Temperature, pressure and

vibration are examples of monitoring parameters. BEVIEL Broglie (2000) has alsoexplained the differences between condition-based maintenance and predictive

maintenance. Unlike the condition-based maintenance policy, predictive maintenance

involves acquiring controlled parameters data which are analyzed to find a possible

temporal trend. This makes it possible to predict when the controlled quantity value

will reach or exceed the threshold values. The maintenance staff will then be able to

plan, depending on the operating conditions, when the component substitution or

revision is really unavoidable.

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THE OPPORTUNITY [10]

Condition Based Maintenance (CBM) promises to deliver improved

maintainability and operational availability of plants while reducing life-cycle

costs

THE CHALLENGE [10]

Prognostics is the Achilles heel of CBM systems - predicting the time to

failure of critical machines requires new and innovative methodologies that will

effectively integrate diagnostic results with maintenance scheduling practices

From PM to TPM

Almost fifty years have passed since Japan imported preventive maintenance

(PM) from the United States. Later adoptions include productive maintenance (PM),

and reliability engineering. What we now refer to as TPM is, in fact, American-style

productive maintenance, modified and enhanced to fit the Japanese industrial

environment.

TPM is now well accepted by the Japanese industrial sector, and is attractingthe attention of Western industrial nations, China and various Southeast Asian

countries.

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Total Productive Maintenance (TPM)

Total Productive Maintenance (TPM) is a maintenance program, which

involves a newly defined concept for maintaining plants and equipment. The goal of the TPM program is to markedly increase production while, at the same time,

increasing employee morale and job satisfaction. (TPM) is a well-defined and time-

tested concept for maintaining plants and equipment. TPM can be considered the

science of machinery health. TPM brings maintenance into focus as a necessary and

vitally important part of the business. It is no longer regarded as a non-profit activity.

Down time for maintenance is scheduled as a part of the manufacturing day and, in

some cases, as an integral part of the manufacturing process. The goal is to hold

emergency and unscheduled maintenance to a minimum.

TPM was introduced to achieve the following objectives:

Avoid waste in a quickly changing economic environment.

Produce goods without reducing product quality.

Reduce costs.

Produce a low batch quantity at the earliest possible time.

Send only non-defective parts to the customers.TPM involves all Denso Associates. The major difference between TPM and other

concepts is that the Production Operators are directly involved in the process of

maintaining their equipment.

The old notion of "I operate the equipment, You Maintain it" is NOT followed.

NIPPOUNDENSOSO was the first company to introduce plant-wide preventive

maintenance in 1960. By then NIPPOUNDENSOSO had made quality circles,

involving the employees participation in implementing Productive Maintenance.Based on these developments NIPPOUNDENSOSO was awarded by the Japanese

Institute of Plant Engineers (JIPE) the distinguished plant prize for developing and

implementing TPM. NIPPOUNDENSOSO of the Toyota group became the first

company to obtain the TPM certification

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Different Generation of Maintenance

First Ggeneration :-Fix it when it broke

Second Generation :

-Scheduled overhauls

-System for planning and controlling work

-Longer asset life

Third Generation :

-Condition Monitoring

-Higher availability and reliability

-Better product quality

-No damage to the environment

-Expert systems

-Multi skills and teamwork

Why TPM? [11]

Because of cost! Proper implementation of TPM leads to a organizedand well equipped firm. Some of the features of the industry where TPM has been

successfully implemented are:

Avoid wastage in a quickly changing economic environment.

Producing goods without reducing product quality.

Reduce cost.

Produce a low batch quantity at the earliest possible time.

Goods send to the customers must be non-defective.

OR

A Safer Workplace

Associate Empowerment An Easier Workload

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Fewer Defects

Fewer Breakdowns-Aims for zero equipment breakdown

Fewer Short Stoppages -Reach zero machine downtime state

Decreased Costs

Decreased Waste

Maintenance goal: more production lower coast

Six losses in the work place / decrease in plant cost: [9]

The objective of TPM is maximization of equipment effectiveness. TPM aims

at maximization of machine utilization and not merely machine availability

maximization. As one of the pillars of TPM activities, Kaizen pursues efficient

equipment, operator and material and energy utilization that is extremes of

productivity and aims at achieving substantial effects. Kaizen activities try to

thoroughly eliminate losses. Six major losses that were identified. Details of which is

given below.

1. Equipment failure causes production downtime. Equipment failure requires

maintenance assistance and can be prevented with the use of appropriate preventive

maintenance actions, developed and applied operating procedures, and design

changes. Most importantly, equipment failure requires an improvement effort that

should be the result of a successful partnership between production and maintenance.

Predictive maintenance techniques such as vibration, oil, and thermo graphic analysis

can be used to anticipate equipment failure. If the failure occurs, it is important to use

Root Cause Failure Analysis (RCFA) techniques to identify the root cause of the

problem and effective and applicable solutions that will eliminate or mitigate the

failure occurrence and impact.

2. Set-up and adjustments: this refers to loss of productive time between product

types, and includes the warm-up after the actual changeover. Changeover time should

be included in this loss opportunity and it should not be part of the planned downtime.

3. Small stops are typically less than 5-10 minutes and they are typically minor

adjustments or simple tasks such as cleaning. They should not be caused by logistics.

4. Speed losses are caused when the equipment runs slower than its optimal or

designed maximum speed. Examples include machine wear, substandard materials,

operator inefficiency, equipment design not appropriate to the application, etc.

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5. Losses during production include all losses caused by less-than-acceptable quality

after the warm-up period.

6. Losses during warm-up include all losses caused by less-than-acceptable quality

during the warm-up period.

5S The Foundation of TPM

TPM starts with 5S. Problems cannot be clearly seen when the work place is

unorganized. Cleaning and organizing the workplace helps the team to uncover

problems. Making problems visible is the first step of improvement.

Growing Expectations of Maintenance

As maintenance passes through various levels of refinement there is a growing

expectation from the manufacturing firms for a unified approach despite diverse

distractions. The technology of maintenance is unending, its marked with finding and

applying cost effective ways of avoiding performance deterioration. Prior to TPM

there were several attempts to boost the maintenance by improving the cost

effectiveness of the machine operations. The changing maintenance techniques can be

illustrated as a time dependent factor.Predictive and preventive maintenance are on peak of new generation of maintenance(TPM) to decrease our plant cost

Firs preventive maintenance

Value of Preventive Maintenance

There are multiple misconceptions about preventive maintenance. One such

misconception is that PM is unduly costly. This logic dictates that it would cost morefor regularly scheduled downtime and maintenance than it would normally cost to

operate equipment until repair is absolutely necessary. This may be true for some

components; however, one should compare not only the costs but the long-term

benefits and savings associated with preventive maintenance. Without preventive

maintenance, for example, costs for lost production time from unscheduled equipment

breakdown will be incurred. Also, preventive maintenance will result in savings due

to an increase of effective system service life.

Long-term benefits of preventive maintenance include:

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Improved system reliability. Decreased cost of replacement. Decreased system downtime. Better spares inventory management.

Long-term effects and cost comparisons usually favor preventive maintenance over

performing maintenance actions only when the system fails.

WHEN DOES PREVENTIVE MAINTENANCE MAKE SENSE

Preventive maintenance is a logical choice if, and only if, the following two

conditions are met:

Condition #1: The component in question has an increasing failure rate. In

other words, the failure rate of the component increases with time, thus

implying wear-out. Preventive maintenance of a component that is assumed to

have an exponential distribution (which implies a constant failure rate) does

not make sense! Condition #2: The overall cost of the preventive maintenance action must be

less than the overall cost of a corrective action. (Note: In the overall cost for a

corrective action, one should include ancillary tangible and/or intangible costs,

such as downtime costs, loss of production costs, lawsuits over the failure of a

safety-critical item, loss of goodwill, etc.)

If both of these conditions are met, then preventive maintenance makes sense.

Additionally, based on the costs ratios, an optimum time for such action can be easily

computed for a single component. This is detailed in later sections .

THE FALLACY OF "CONSTANT FAILURE RATE" AND "PREVENTIVEREPLACEMENT" [12]

Even though we alluded to the fact in the last section of this on-line

reference, Availability, it is important to make it explicitly clear that if a component

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has a constant failure rate ( i.e . defined by an exponential distribution), then preventive

maintenance of the component will have no effect on the component's failure

occurrences. To illustrate this, consider a component with an MTTF = 100 hours,

or = 0.01, and with preventive replacement every 50 hours. The reliability vs. time

graph for this case is illustrated in Figure 1.1. In Figure 1.1, the component is

replaced every 50 hours, thus the component's reliability is reset to one. At first

glance, it may seem that the preventive maintenance action is actually maintaining the

component at a higher reliability.

Figure 1.1: Reliability vs. time for a single component with an MTTF = 100 hours, or =

0.01, and with preventive replacement every 50 hours.

However, consider the following cases for a single component:

Case 1: The component's reliability from 0 to 60 hours:

With preventive maintenance, the component was replaced with a new one at

50 hours so the overall reliability is the reliability based on the reliability of

the new component for 10 hours, R(t = 10) = 90.48%, times the reliability of

the previous component, R(t = 50) = 60.65%. The result is R(t = 60) = 54.88%. Without preventive maintenance, the reliability would be the reliability of the

same component operating to 60 hours, or R(t = 60) = 54.88%.

Case 2: The component's reliability from 50 to 60 hours:

With preventive maintenance, the component was replaced at 50 hours so this

is solely based on the reliability of the new component, for a mission of 10

hours, or R(t = 10) = 90.48%.

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Without preventive maintenance, the reliability would be the conditional

reliability of the same component operating to 60 hours, having already

survived to 50 hours, or .

As it can be seen, both cases, with and without preventive maintenance, yield the

same results.

DETERMINING PREVENTIVE REPLACEMENT TIME

As mentioned earlier, if the component has an increasing failure rate, then a carefully

designed preventive maintenance program is beneficial to system availability.

Otherwise, the costs of preventive maintenance might actually outweigh the benefits.

The objective of a good preventive maintenance program is to either minimize the

overall costs (or downtime, etc.) or meet a reliability objective. In order to achieve

this, an appropriate interval (time) for scheduled maintenance must be determined.

One way to do that is to use the optimum age replacement model, as presented next.

The model adheres to the conditions discussed previously, or:

The component is exhibiting behavior associated with a wear-out mode. That

is, the failure rate of the component is increasing with time. The cost for planned replacements is significantly less than the cost for

unplanned replacements.

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Figure 1.2: Cost curve for preventive and corrective replacement.

Figure 1.2 shows the Cost per Unit Time vs. Time plot. In this figure, it can be seen

that the corrective replacement costs increase as the replacement interval increases. In

other words, the less often you perform a PM action, the higher your corrective costs

will be. Obviously, the longer we let a component operate, its failure rate increases to

a point that it is more likely to fail, thus requiring more corrective actions. The

opposite is true for the preventive replacement costs. The longer you wait to perform

a PM, the less the costs; while if you do PM too often, the higher the costs. If we

combine both costs, we can see that there is an optimum point that minimizes the

costs. In other words, one must strike a balance between the risk (costs) associated

with a failure while maximizing the time between PM actions.

OPTIMUM AGE REPLACEMENT POLICY [12]

To determine the optimum time for such a preventive maintenance action

(replacement), we need to mathematically formulate a model that describes the

associated costs and risks. In developing the model, it is assumed that if the unit fails

before time t , a corrective action will occur and if it does not fail by time t , a

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preventive action will occur. In other words, the unit is replaced upon failure or after a

time of operation, t , whichever occurs first.

Thus, the optimum replacement time can be found by minimizing the cost per unit

time, CPUT (t ). CPUT (t ) is given by:

(5)

Where:

R(t ) = reliability at time t . C P = cost of planned replacement. C U = cost of unplanned replacement.

The optimum replacement time interval, t , is the time that minimizes CPUT (t ). This

can be found by solving for t such that:

(6)

Or by solving for a t that satisfies Eqn. (7):

(7)

Interested readers can refer to Barlow and Hunter [2] for more details on this model.

INTRODUCTION TO REPAIRABLE SYSTEMS EXAMPLE 2

The failure distribution of a component is described by a 2-parameter Weibull

distribution, with = 2.5 and = 1000 hours.

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The cost for a corrective replacement is $5. The cost for a preventive replacement is $1.

Estimate the optimum replacement age in order to minimize these costs.

SOLUTION TO INTRODUCTION TO REPAIRABLE SYSTEMS EXAMPLE 2

Prior to obtaining an optimum replacement interval for this component, the

assumptions of Eqn. (5) must be checked. The component has an increasing failure

rate, since it follows a We bull distribution with greater than one. Note that if = 1,

then the component has a constant failure rate and if < 1, it has a decreasing failure

rate. If either of these cases exist, then preventive replacement is unwise.

Furthermore, the cost for preventive replacement is less than the correctivereplacement cost. Thus, the conditions for the optimum age replacement policy have

been met. Using Block Sim, the failure parameters can be entered in the component's

Block Properties window. Select "Optimum Replacement" from the Block menu,

enter the costs and compute the optimum time, 493.0470. Figure1.3 illustrates this.

Figure 1.3: Using BlockSim's Optimum Replacement utility to obtain the results in

Example 2.

Figure 1.4 shows a plot illustrating the cost per unit time.

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Figure 1.4: Graph of cost vs. replacement time for Example 2.

DISCUSSION ON INTRODUCTION TO REPAIRABLE SYSTEMS EXAMPLE2

The effect of the corrective/preventive cost ratio on the optimum replacement

interval is plotted in Figure 7.7. It can be seen that as the cost ratio increases, the

optimum replacement interval decreases. This is an expected result because the

corrective replacement costs are much greater than the preventive replacement costs.

Therefore, it becomes more cost effective to replace the component more frequently

before it fails.

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Figure 1.5: Replacement interval as a function of the corrective/preventive cost ratio.

Second predictive maintenance

Predictive maintenance programs provide businesses with valuable insight into

the condition of their in-service process equipment, and are crucial in keepingindustrial processes online, streamlining maintenance schedules, and minimising

repair expenses. Todays industrial environment can be unforgiving, driven by the

quest for quality, throughput and arguably most importantly, profit. With many

businesses operating 24 hours a day seven days a week, it is crucial that their

industrial processes are kept online, and free from interruption. To achieve this,

individual process equipment elements and machinery units must perform at an

optimum level across a range of demanding operating conditions, all while remaining

fault-free. Here, the expectation from the industrial sector has never been higher. An

unavoidable by-product of any industrial process is the wear and tear on individual

pieces of process equipment and their internal components. Breakages, leaks,

overheating and complete breakdowns can lead to lengthy process shutdowns and lost

revenue. These worse-case-scenario breakdowns become more prevalent when

process equipment is neglected or poorly maintained. To ensure process equipment

and machinery are kept in optimum working order, a systematic maintenance program

is vital. The ability to accurately predict, and then address, the maintenance

requirements of individual pieces of equipment goes a long way to maximising

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uptime and avoiding costly process shutdowns. Here, predictive maintenance

strategies lead the way. Offering crystal ball-like insight into the condition of onsite

process equipment, predictive maintenance programs are fast becoming an essential

component of modern industrial processes.

React, plan or predict?The ongoing maintenance of process equipment is a necessary operating

overhead experienced across nearly every application in the industrial sector.

Equipment, such as motor gear-units, drive some of industrys most vital processes

and, as a result, need to be kept in good working order. This is often easier said than

done. According to SEW-Eurodrive applications engineer, Luke Schmidt, gear-unit

maintenance has traditionally been carried out three different ways--reactive, plannedor predictive. Reactive maintenance is the least efficient maintenance strategy, he

says. Addressing system faults and breakdowns after they occur, means processes

can be offline for long periods while spare parts are procured and repairs made.

Usually, going offline for any period of time means loss of revenue, which is

unacceptable. Furthermore, specialist service staff can be expensive, especially at

short notice or unusual times. Planned maintenance programs go some way to

ensuring the wellbeing of gear-units, but can be viewed as unnecessary or wasteful,

depending on the application. Regular planned maintenance can be beneficial, but is

often not very cost-effective, says Schmidt. It can result in unnecessary

maintenance being carried out, which wastes time, materials, labour resources and

money. Unwarranted oil changes and parts replacement, in particular, can have

significant environmental impact.

Further difficulties can be encountered, as planned maintenance activities are often

carried out over summer shutdown periods--busy peak periods for maintenance staff.

According to SEW-Eurodrive Strategic Marketing and Product Manager, Darren

Klonowski, more sophisticated maintenance strategies, such as a predictive

maintenance program offer clear advantages. Predictive maintenance allows

businesses to monitor their process equipment, determine the condition and schedule

maintenance accordingly, he says. It ensures equipment life is maximised, and helps

keep machinery online, preventing unplanned downtime.

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Condition predictionPredictive maintenance programs are centered around condition monitoring

processes. Here, field mounted sensors continuously detect and collect an array of

performance parameters unique to individual machines. The collected data is then

used to establish the real condition of the machine and its components. This kind of

insight allows maintenance technicians to take preventative action before a failure

occurs, therefore avoiding the consequences of that failure. Condition monitoring

permits the early detection of the initial stages of component wear, which if left

unaddressed, can lead to catastrophic

failures, says Klonowski. This level of

foresight is obviously a real benefit,

particularly with respect to gear-units,

which are often subjected to continuous

operation under extremely demanding

conditions. Being able to monitor the

condition of bearings, gears, drive shafts

and lubricating oil gives technicians a

detailed understanding of what

maintenance tasks needs to be carried outin order to extend the gear-unit life and

keep it online longer. Such field-

mounted devices monitor a number of

gear unit parameters, including vibration,

oil level and temperature, and brake-

wear. By monitoring these gear-unit

parameters, on-sitetechnicians can accurately plan maintenance activities, explains Schmidt. It means

maintenance is carried out only when and where it is required which maximizes

component life and sees maintenance resources utilized efficiently.

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Predict to protect profitPredictive maintenance programs effectively address two primary

considerationsthey protect expensive process equipment, as well as entire critical

process lines.While there is merit in monitoring individual gear-units for the sole

purpose of avoiding costly repair bills, often it is the protection of the process as a

whole that is more important, says Klonowski. The gear-unit being monitored may

be relatively inexpensive, but it might be responsible for driving a production line

with a high throughput rate. If this line goes offline, the business can lose money at an

alarming rate.Its not just the gear-unit that should be looked at, adds Schmidt. Its

the role of the piece of equipment in the process. The cost, production impact and

flow-on affects associated with that piece of equipment going offline must be

considered. A less-expensive gear unit might be responsible for driving a process that

has a production output rate of $50,000/hr. Predictive maintenance programs go a

long way to ensuring these process stay online, while saving money According to

Klonowski, predictive maintenance strategies are more costeffective when compared

with reactive and planned maintenance schemes . Reactive maintenance results in

periods of minimal maintenance followed by periods of extreme activity when urgent

or emergency repairs are carried out--usually at an inflated rate, he says. Planned

maintenance delivers some cost benefits, but can result in unnecessary and costlymaintenance being performed.

Detect, diagnose, ActAt the heart of predictive maintenance installations lies a network of field-

mounted condition monitoring devices or sensors linked via I/O to an on-board

frequency inverter or central programmable logic controller (PLC). Each inverter or

PLC can be connected to the plant-wide supervisory control and data acquisition

(SCADA) system, and internet mail server via an Ethernet link . Such a system

architecture provides real flexibility, says Schmidt. It allows machine performance

and condition data to be easily detected, diagnosed and acted on. It can be configured

to alert key personnel, once a pre-determined alarm-point or milestone has been

reached. The alarm can be sent to an on-site HMI (Human-Machine Interface),

SCADA or PC, or alternatively to an off-site control centre, mobile phone or pager.

Predictive maintenance strategies are especially valuable in remote locations where

gear-unit breakdown and unplanned downtime can take extended periods of time to

remedy. By remotely monitoring applications in isolated or unsupervised areas,

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technicians can accurately predict maintenance requirements and plan ahead says

Schmidt. It means maintenance resources can be deployed at a time that permits

repairs and upkeep to be carried out on multiple pieces of equipment at the same

location.

In addition to being integrated into plant-wide communications and control systems,

many field-mounted sensors are equipped with onboard displays and indicators.

Visual indicators provide maintenance staff with an immediate indication of the

gear-unit condition, says Schmidt. Some devices actually show the hours to next

service of the gear-unit. More sophisticated devices, such as vibration analysis

sensors, allow the early detection of roller bearing and gearing damage, as well as

gear-unit unbalance and resonance problems.

As pressure mounts to keep industrial wheels turning around the clock, predictive

maintenance is emerging as vital factor in efficient industrial processes. With the

ability to establish the current and future condition of in-service process equipment,

predictive maintenance is set to become more than a maintenance option, but rather a

necessity.

Predictive Maintenance - Cost Effect

1-How Can Get The Most Gain of Predictive Maintenance?

2-How Can Use Predictive Maintenance Useful and careful?

1-1 In first , I will say that statistics show maintenance is not lost of money ;

maintenance is the best way to save our equipment and facilities life-time . Predictive

Maintenance is also a intelligent method to discover fault before shutdown, THEN

MAINTENANCE IS A INVESTMENT.

Planning aid to predictive maintenance [2]Three key principles in best practice maintenance planning will be introduced

within this article those being The Maintenance Planning Framework; The Shut

Calendar, and; The Planners Plan. These three vital tools should be within any

Maintenance Planners toolbox. The most demanding call on maintenance resources

comes when a plant or facility is shutdown for an extended period of time for

scheduled maintenance. Usually a large complement of work must be scheduled into a

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relatively short period of time. Work schedules may have to be modified. Special

equipment may have to be rented. Contractors may have to be hired to fill additional

labor requirements and special needs. Scheduled shutdowns provide unique

opportunities to a maintenance department not normally available during standard

operation or even during short shutdown periods. Lost capacity can be restored to

An overtaxed facility during an extended shutdown. Major equipment overhauls can

be performed to help prevent future unscheduled shutdowns. Government mandated

inspections and repairs can be accomplished during a shutdown, bringing a plant into

better state of compliance. In order to achieve the above and ensure that the

maintenance activities are completed efficiently and effectively, maintenance

planning needs to be well structured. Based on this, the main objectives and functions

of maintenance planning should be of cussed on ensuring that:

Proactive preventative maintenance tasks are adequately planned, scheduled and

implemented in accordance with Business Centered Maintenance.

All maintenance activities that improve the reliability and availability of the

operating equipment are completed on time.

All maintenance activities are undertaken in a planned and proactive manner which

increases optimises the productivity of the maintenance personnel.

All resources are readily available at the right time to allow maintenance to be

completed in accordance with the maintenance plan.

All personnel are adequately informed about what maintenance tasks are to be

completed, when this is to occur and on what equipment.

Information is appropriately captured and recorded to allow maintenance personnel

to make informed and accurate decisions about what maintenance needs to be

performed, and when to perform this so that the operating equipment meets the needs

of the production department in a timely and cost effective manner. Alternatively,maintenance planning can be referred to as ensuring that the maintenance activities

are completed at the right time, in the right manner, with the right tools and the right

skilled resources that is, it is all about ensuring that it is done right the first time.

This can be further simplified in terms of the role / function that must be provided /

undertaken by the Maintenance Planner in order to ensure that the maintenance

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activity / job is done right the first time

How can escape of too much PM and how can releaseof plant cost?

16 Golden Way to save time and money on preventive maintenance:

1. PM Consumes Too Many Resources: Many maintenance managers believe

their PM program is simply bigger than it should be. They feel like they dont have

enough manpower to manage all of their PMs along with the other important

maintenance work, too.

2. Lack of Results: Despite all of the time and money being spent on

preventive maintenance, there are still way too many unexpected equipment failures.

Case in point: During a recent chemical plant tour, the frustrated maintenance

manager said, We just PDM that machine, and it failed a short time later anyway. So

why didnt we catch the problem with the PM? Why indeed. So in a nutshell, the

problem with preventive maintenance is that it takes too much time and produces too

little results.

The No. 1 Law You Should Know [6]The number one law of economics you need to know is based on a principle

discovered over 200 years ago. Youve probably heard of it its called the Law of

Diminishing Returns. As any good MBA student can tell you, this law states that as

one production factor increases while the others remain constant, overall production

decreases after a certain point. In plain English, it means as you increase preventive

maintenance, production output eventually decreases. The following chart illustrates

this. You see, theres a fine line between doing too much, too little and just the right

amount of preventive maintenance. Clearly, theres a point at which increasing PM

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hurts the bottom line. The reason? Simple. Most PM procedures require that the

equipment is shut down. That means uptime goes down, so production output

eventually goes down too. Meanwhile, maintenance costs go up. So how much

preventive maintenance is too much? According to a private study, best practice

programs generate 15% of their maintenance work from PM inspections. Another

15% is corrective work identified by those inspections.

The real truth about PM

By definition, all PMs are time-based. That means either calendar time or operating

time dictates when an asset should be inspected, cleaned, adjusted, replaced or

reconditioned. But is there really a direct relationship between the time equipment

spends in service and the likelihood it will fail? In short, the answer is no. The truth is,

most equipment failures are not age related. In fact, for complex systems, the majority

of failures will occur at random. Consider the facts. The following graphs demonstrate

failure probabilities relative to the age of the equipment itself: First, its important to

understand this data comes from the airline industry, where maintenance and

operations standards are exceptionally high. That gives us a true picture of how

equipment fails when it is maintained and operated correctly. The reality is, 89% of

equipment failures are not age-related. Therefore, theres no amount of time-based

preventive maintenance which can manage these failures effectively. Thats why

using time as the primary basis for your maintenance strategy is inherently flawed. It

will have very little impact on overall reliability. From a risk standpoint, its much

safer to assume that equipment failures can happen at any time.

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CONSIDER PDM FIRST

No matter what kind of industry youre in, predictive maintenance (PdM) is

almost always more cost-effective than people as your first line of defense against

equipment failures. Based on studies done in major industries including chemicals,

paper, metals, automotive and power generation, something interesting happens as

more equipment is added to the PDM program.

OVERALL MAINTENANCE COSTS GO DOWN. HERES WHAT THE DATASHOWS: [6]

As you can see, there is a direct

correlation between high levels of PdMand low overall maintenance costs

measured as a percent of the assets

replacement value. On the other hand,

the data also shows that increasing the

size of a PM program directly results in

higher maintenance costs. The graph

below illustrates:

Why is the case? Consider the facts:

Predictive maintenance inspections can identify problems much earlier on the failure

curve than preventive maintenance (see chart below). So PDM gives you more time to

plan, schedule, make the repairs and avoid unscheduled downtime .

And thats really the secret, that predictive maintenance drives more planned work.

What that means is:

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Jobs done faster, safer and at a lower cost.

Studies show that a well-planned job takes only half as much time to execute as an

unplanned job.

Each dollar invested in planning saves three to five dollars during execution

And dont forget, most predictive maintenance

inspections require equipment to be up and

running. That means downtime for maintenance

is minimized a key issue at plants where the

value of downtime is $5,000, $10,000, $20,000

an hour or more.

CONSIDER THE TIME FACTOR [6]

Do you struggle to find the time to perform PMs? Is there a significant

number of PMs not being completed on time? Are PMs frequently deferred? If so,

thats another red flag. Look, all PMs are time-based, so its important to do them

on time. What that means is, a PM should be done within a timeframe of plus-or-

minus 10% of its due date. For example, if a PM is scheduled every thirty days, it

should be completed within a three-day window of the due date. The following chart

illustrates:Frankly, one of the hidden problems of preventive maintenance is theres no

immediate, observable consequence of not doing it. For example, if you dont change

the oil in your car at 3,000 miles, its probably not going to break down the next day.

However, you cant defer preventive maintenance if you want to have an effective

reliability program. PM may not be the most urgent or exciting work you do, but its

definitely among the most important.

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Reducing Maintenance Cost in a Tough Economic Climate [8]The current economic climate dictates that cost management is a critical

activity for many companies and their managers. Maintenance is very often seen as an

area where cost cutting targets can be easily and quickly achieved. Many maintenance

managers take the view that this type of philosophy always ends up with increased

costs in the future. This is not true in many cases.

The most maintenance departments are more reactive than they should be and

because of this, they over spend and underperform. Costly, inefficient and ineffective

Preventive Maintenance (PM) programs result in a vicious cycle of reactive

maintenance. High levels of reactive maintenance destroy the ability to plan and

schedule and reduce labor productivity by 50% or more (Palmer 1999). Reactive

maintenance also results in massive inventories of, or express delivery charges for,

spare parts. The combination of ineffective PM and high levels of reactive

maintenance results in a massive overspend on maintenance and provides fertile

ground for cost reduction.

It is not uncommon for a company to

consume twice the maintenance labor it

needs.

For example, the Carbon productionfacility in an Aluminums Smelter

reduced its annual maintenance labor by

over 4,000 man hours, while, at the same

time, increasing plant availability. The

table below shows the detail.

The company reported that this was done by:

Reviewing the various options of scheduled discard vs. condition based strategies(especially in lubrication tasks)

Gaining a clear understanding of the reasons for each PM task and documenting

them. Eliminating tasks that were not linked to cost effective prevention of failure

Setting inspection frequencies to match rates of equipment function deterioration

Avoiding duplication of effort between various trades and operations groups.

The reduction was not a paper figure the labor reductions were real savings

computed by comparing one years executed hours to the next.

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Chapter 3

In Conclusion [3] , [1]

Many failures happen suddenly and randomly. Because of this some failures

will happened regardless of the maintenance program. In such case defect elimination

or consequence mitigation are the only options to reduce the impact of failure.

Objective and manufacturing are cost, quality, and delivery.

Maintenance is a total to achieve these objective

Maintenance must be integrated into the manufacturing function

Maintenance strives to eliminate downtown and minimize breakdown

cost

Computerized maintenance management software, thats easier to use,

that it is to say. Formal scheduling answer the question how much

work should we do next week. Scheduling is a matter of control.

CBM (condition based maintenance) Also referred as prediction

maintenance, this is a method where by facility detection is constantly

or periodically monitored by facility diagnosis and maintenance is

conducted when an abnormality is found.

CM (corrective maintenance) is the maintenance wore which improves

the existing \facility to a state where it is free of breakdown (reliable),

easy to check and repair (good maintenance), easy to operate and

operates safety.

Predictive maintenance at dell includes standardize routes preformed

by all maintenance technicians. Routes utilize visual inspection,

ultrasound, vibration, and infrared. Technicians are assigned to an area

and given short duration, dedicated routes to complete. Scheduling is

key to assure equipment, tools and technician availability.

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Result

For zero failure maintenance of basic condition observe the operating

condition recover deterioration increase operating and maintenance skill.

THEN MAINTENANCE IS A INVESTMENT AND ITS NOT LOST

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Chapter 4

References

[1] Mark Burgett, Rich young, (2007), a journey to predictive maintenance, AMMJ,

[2] Mike Killick, Gary Thomas, (2004)a journey to best practice MaintenancePlanning, AMMJ,

[3] Doc Palmer, (2006), a journey to Maintenance Scheduling, AMMJ

[5] Kamran Shahanaghi, Seyed Ahmad Yazdani, (2009), a journey to Analyzing theeffects of implementation of TPM in the manufacturing companies, World journal of Modelling and Simulation

[6] Andy page, George Karalexis, (2009), a journey to ways to save time and Moneyon preventive Maintenance, AMMJ, vol 22, no 23,page 22

[7] SEW-Eurodrive,(2009) a journey to the Predictive Maintenance crystal ball,AMMJ

[8] Steve Turner,(2009), a journey to Peducing Maintenance Costs in a toughEconomic climate, AMMJ

[9] Dr. j.Venkatesh, (2007) six losses in the work place, types of maintenance, 2-15 pages

10] Dr. George Vachtsevanos,(2003), Cost and complexity trade-offs in prognostics NDIA Conference on intelligent vehicles in Travers city

[11] Dr.N.Suren Dwivedi, (2005), Total Product Maintenance in Lean Manufacturing,University OF Louisiana at Lafayette

[12] Barlow, R. and L. Hunter, Optimum Preventive Maintenance Policies,Operations Research, Vol. 8, pp. 90-100, 1960. [book]

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