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International Journal of Industrial Engineering Research and Development (IJIERD), ISSN 0976 –
6979(Print), ISSN 0976 – 6987(Online), Volume 5, Issue 1, January - February (2014), © IAEME
10
STUDY RELIABILITY CENTERED MAINTENANCE (RCM) OF
ROTATING EQUIPMENT THROUGH PREDICTIVE MAINTENANCE
Mariam Altaf Tarar
Lecturer, Institute of Quality & Technology Management,
University of the Punjab, Lahore, Pakistan
ABSTRACT
Reliability Centered Maintenance (RCM) is the framework of preserving system
functions, rather than preserving physical asset. RCM is used to evaluate planned
maintenance schedule that will offers availability of equipment with both reliability and
maintainability. This paper presents ABC Automobile Company case, where planned
maintenance is possible with application of predictive maintenance strategy, which enables to
take decision of maintenance action with evidence and reduce unneeded maintenance. The
main principle of predictive maintenance is examining the important performance
characteristics of equipment to select the most indicative parameters of condition which reflects
functional failures. In proposals, vibration is selected as an important performance
characteristic of rotating components. Through vibration monitoring several mechanical
failures can be effectively predicted. Signals (such as through the use of vibration monitoring)
emanating from the condition monitoring of equipment are frequently interpretative as per
manufacturer’s recommendations, use of an expert system, or the threshold values established
through the experience of inspectors are used (Wiseman and Jardine, 1999).
The maintenance strategy adopted by ABC Automobile Company is preventive
maintenance with manually collected condition monitoring data. That data usually indicates
abnormality when actually failure occurs. This paper includes determination of the
effectiveness of existing maintenance strategy and its comparisons with other strategies with
improvement proposals. It outlines RCM analysis process and a test case of fans of paint
booth process.
This study concludes that RCM enables to evaluate planned maintenance action and
incase of rotating components the vibration monitoring technique can be effectively used in
predictive maintenance strategy. The paper reveals that the ABC Automobile Company can
INTERNATIONAL JOURNAL OF INDUSTRIAL ENGINEERING
RESEARCH AND DEVELOPMENT (IJIERD)
ISSN 0976 – 6979 (Print) ISSN 0976 – 6987 (Online)
Volume 5, Issue 1, January - February (2014), pp. 10-30
© IAEME: www.iaeme.com/ijierd.asp
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IJIERD
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International Journal of Industrial Engineering Research and Development (IJIERD), ISSN 0976 –
6979(Print), ISSN 0976 – 6987(Online), Volume 5, Issue 1, January - February (2014), © IAEME
11
achieve enhanced manufacturing performance leading to competitive advantage with
successful RCM implementation through predictive maintenance.
Keywords: Reliability Centered Maintenance (RCM), Predictive Maintenance, Preventive
maintenance, Condition monitoring, Performance monitoring, Vibration monitoring.
1.2 Background Maintenance is routine recurring work, which is necessary to retain equipment in a
state in which it can perform its intended function. Maintenance is performed to ensure
equipment availability in industry so as to compete in global market. Maintenance has
changed more than any other management discipline during the past twenty years. In early
ages, the maintenance strategy was breakdown maintenance, as there was no awareness of
downtime. But with passage of time, increased complexity of machines led to the prevention
maintenance in second generation, and then maintenance strategies and objectives have
rapidly changed from preventive maintenance to condition monitoring. In this era, the
importance of effectiveness of operational equipment raised, which is dependent on plant
capacity (Raouf, 2004). So, the concluded strategy must have a balance between maintenance
cost and plant reliability.
Usually most of the industries in Pakistan follow preventive maintenance strategy or
scheduled maintenance. According to Herbaty, Preventive maintenance comprises of periodic
activities performed at predetermined time interval or after the specified amount of
equipment usage to keep it in proper working condition and to prevent it from breakdowns
(Herbaty, 1990).
In 1960s, a new concept, Reliability Centered Maintenance (RCM) evolved. Initially
RCM was used in aircraft industries, and it was oriented towards airplanes maintenance
(Dekker, 1996). RCM is a structured framework and a logical process of optimizing
maintenance resources for physical asset’s maintenance in its operating context. RCM is
focused on preserving system functions, rather than preserving physical asset. RCM analyzes
the functions, potential failures of equipment and it is a seven-review step philosophy to
evaluate “inherent reliability”, with risk management. RCM is possible with the selection of
an effective maintenance strategy that will offer “inherent reliability” of equipment (Samanta
et al., 2001).
1.3 Problem Statement In preventive or routine maintenance of equipment, catastrophic failures are still
likely to occur; maintenance may be performed more often than may be necessary; in such
unneeded maintenance there are chances of components incidental damage; assets taken off-
line often for maintenance services, and was mostly labor intensive. In ABC Automobile
Company, preventive maintenance is followed with actions of cleaning, lubrication,
tightening, adjustment, and parts replacement at specified time interval. Sometimes unneeded
preventive maintenance actions are performed, and just performed to fulfill schedule demand.
For such maintenance activities, equipment is taken off line and these activities are usually
labor intensive.
Secondly, ABC Automobile Company daily collects condition monitoring data. That
data are based on manual checking or observing. That is why data do not indicate any upper
or lower limit of any parameters. It indicates abnormality when actually failure occurs. The
pitfall of this method is the daily monitoring i.e. every 3hours that require extra manpower to
check and handle this manually collected inappropriate data.
International Journal of Industrial Engineering Research and Development (IJIERD), ISSN 0976 –
6979(Print), ISSN 0976 – 6987(Online), Volume 5, Issue 1, January - February (2014), © IAEME
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In case of critical equipment, preventive maintenance activities are hard to schedule
so any other strategy can be more economical. The strategy through that may be beneficial is
the one in which maintenance is performed only when necessary and thus it will provide
better asset availability and reliability.
1.4 Objective The objective of this paper is to study predictive maintenance strategy and the
benefits of its implementation for the equipment at ABC Automobile Company, instead of
preventive maintenance. This study focuses on rotating equipment (e.g. motors, pumps,
conveyors, compressors etc.), where vibration monitoring can be implemented through RCM.
1.5 Gap Analysis In ABC Automobile Company, preventive maintenance strategy is followed on the
basis of schedule activities at the specified time intervals. So there is a margin to improve
through application of Reliability Centered Maintenance (RCM). This improvement is
possible with predictive maintenance requirements instead of carrying out routine or
scheduled maintenance. Performance parameters and other condition monitoring parameters
can be identified and analyzed to find out the root cause of failure. As these performance
parameters and other condition monitoring parameters are the indicators of equipment
condition and performance decline. So, their analysis will provide the optimum time to plan
and perform maintenance action before failure occurs. It will facilitate maintenance staff in
decision making by providing evidence.
1.6 Significance of the Research This paper is based on ABC Automobile Company existing maintenance strategy, and
its improvement proposal through RCM. For this purpose, an exhaustive and logical search of
maintenance literature is conducted, evaluated different maintenance strategies and their
comparison with each other. This comparison helps to select an appropriate maintenance
strategy for critical and non critical equipment. It will discuss implementation plan of RCM
through predictive maintenance, and also shows a test case of critical equipment to find out
root cause of the decline in performance.
1.7 Methodology The research approach is qualitative and primary data sources are used to collect data.
The method of data collection is observation (non-participant) and structured interviewing of
maintenance staff of ABC Automobile Company Ltd and condition monitoring Company.
This study primarily describes their existing situation and problems facing with preventive
maintenance strategy on account of the different opinions people have about an issue and
observations, and data analysis with proposals to improve this situation. A test case is
presented to analyze the validity of proposals to improve this situation.
2.1 Existing Condition Monitoring Data In ABC Automobile Company, preventive maintenance is followed with manual daily
condition monitoring of sheets. Few of the critical equipment’s monitoring parameters are
shown below with their standard ratings;
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6979(Print), ISSN 0976 – 6987(Online), Volume 5, Issue 1, January - February (2014), © IAEME
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Table 1: Existing Condition monitoring data
Equipment: PO Booth # 1 Exh. Fan
Sub-
Equipment Exh. Fan Spray Booth Exh. Fan Setting Room
Monitoring
Items Noise Vibra B.Con. B.Noise Noise Vibra B. Noise
B.Noise
Standard
Rating None None T~N~L None None None None None
Equipment: Top Coat Booth # 1 Fans
Sub-
Equipment Clear Coat# 2 Exhaust Fan
Setting Room Exhaust Fan
Monitoring
Items Noise Vibr.
B.
Noise
B.
Cond. Noise Vibr. B. Noise B. Cond.
Standard
Rating None None None T~N~L None None None T~N~L
Equipment: New Small Compressor
Sub-
Equipment Motor Oil Belt
I/P
Valves
Of
Tank
Air tank Compressor
Moisture
Trap of
Man
Tank
Moisture
Trap of
compressor
Monitoring
Items Noise Level Tension Open Pressure Noise
Manual
Drain
Manual
Drain
Equipment: Cooling Water Circulation System
CWP 01 A CWP 03 BA CWP 03 B
Sub-
Equipment
Pump
Bearing
Motor
Bearing
Motor
Cool
Fan
Pump
Bearing
Motor
Bearing
Motor Cool
Fan
Pump &
Motor
Bearing
Motor Cool
Fan
Monitoring
Items Noise Noise Loose Noise Noise Loose Noise Loose
Standard
Rating None None None None None None None None
Legends : OK=O,NG=X, Vibra.=Vibration, B.Con.= Belt Condition,
T~N~L= Tight~Normal~Loose, B.Noise=Bearing Noise.
In Table 1, noise, vibration, belt looseness and bearing noise of paint Booth # 1
Exhaust fan is monitored on basis of manual observation of maintenance staff, which is
attribute data and not clarifying quantitative data of these parameters. So it is not guaranteed
to predict equipment condition. Similar inspection is followed in case of new small
compressor and cooling water circulation system.
2.2 Analysis of existing Maintenance strategy With the existing way of monitoring parameters, it is unable to predict failure
accurately. The data of vibration or noise are based on manual checking or hearing. That is
why data are not indicating any upper or lower limit of these parameters. It indicates
International Journal of Industrial Engineering Research and Development (IJIERD), ISSN 0976
6979(Print), ISSN 0976 – 6987(Online), Volume 5, Issue 1, January
abnormality when actually failure o
every 3hours that require extra manpower to check and handle this manually collected
inappropriate data. As shown in Table 1, noise, vibration, belt looseness and bearing noise of
paint Booth # 1 Exhaust fan is monitored on basis of manual observation of maintenance
staff, which is not guaranteed to predict equipment condition. Similar inspection is followed
in case of other equipment as shown in Table 1.
When failure of critical equipment is focuse
many mechanical failures can be ignored and predict timely, in case of proper health
monitoring of rotating equipment.
2.3 Proposed Maintenance Action Plan On rotating equipment, predictive maintenance is a suit
failures of particular equipment and control proper working of the whole station. So,
machines and optimum monitoring techniques are selected and predictive maintenance can be
followed. With the help of condition monitoring of part
vibration monitoring equipment, their scheduled maintenance can be planned as per
requirement of machine.
The implementation of Predictive maintenance in addition to preventive maintenance
is possible with the following steps;
1. Classify equipment for maintenance,
2. Select RCM strategy,
3. Implementation of Predictive maintenance.
2.3.1 Classify equipment for maintenance First step in implementing RCM is to select or classify equipment for appropriate
maintenance strategy. The two methods used to select equipment are Criticality Analysis and
Selection Question method that is usually employed.
Figure 1: Classifying Equipment for maintenance
International Journal of Industrial Engineering Research and Development (IJIERD), ISSN 0976
6987(Online), Volume 5, Issue 1, January - February (2014), © IAEME
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abnormality when actually failure occurs. The pitfall of this method is the daily monitoring
every 3hours that require extra manpower to check and handle this manually collected
inappropriate data. As shown in Table 1, noise, vibration, belt looseness and bearing noise of
haust fan is monitored on basis of manual observation of maintenance
staff, which is not guaranteed to predict equipment condition. Similar inspection is followed
in case of other equipment as shown in Table 1.
When failure of critical equipment is focused and analyzed then it is concluded that
many mechanical failures can be ignored and predict timely, in case of proper health
monitoring of rotating equipment.
2.3 Proposed Maintenance Action Plan On rotating equipment, predictive maintenance is a suitable strategy to prevent
failures of particular equipment and control proper working of the whole station. So,
machines and optimum monitoring techniques are selected and predictive maintenance can be
followed. With the help of condition monitoring of particular rotating components, through
vibration monitoring equipment, their scheduled maintenance can be planned as per
The implementation of Predictive maintenance in addition to preventive maintenance
g steps;
Classify equipment for maintenance,
Implementation of Predictive maintenance.
Classify equipment for maintenance First step in implementing RCM is to select or classify equipment for appropriate
The two methods used to select equipment are Criticality Analysis and
Selection Question method that is usually employed.
Classifying Equipment for maintenance
International Journal of Industrial Engineering Research and Development (IJIERD), ISSN 0976 –
February (2014), © IAEME
ccurs. The pitfall of this method is the daily monitoring
every 3hours that require extra manpower to check and handle this manually collected
inappropriate data. As shown in Table 1, noise, vibration, belt looseness and bearing noise of
haust fan is monitored on basis of manual observation of maintenance
staff, which is not guaranteed to predict equipment condition. Similar inspection is followed
d and analyzed then it is concluded that
many mechanical failures can be ignored and predict timely, in case of proper health
able strategy to prevent
failures of particular equipment and control proper working of the whole station. So,
machines and optimum monitoring techniques are selected and predictive maintenance can be
icular rotating components, through
vibration monitoring equipment, their scheduled maintenance can be planned as per
The implementation of Predictive maintenance in addition to preventive maintenance
First step in implementing RCM is to select or classify equipment for appropriate
The two methods used to select equipment are Criticality Analysis and
International Journal of Industrial Engineering Research and Development (IJIERD), ISSN 0976 –
6979(Print), ISSN 0976 – 6987(Online), Volume 5, Issue 1, January - February (2014), © IAEME
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2.3.2 Comparison of Maintenance Strategies The following Table 2 summarizes the differences between a numbers of maintenance
strategies:
Table 2: Comparison of Maintenance strategies
Maintenan
ce Strategy
Maintenance
Strategy Brief Concept
Maintenance
Approach
Frequency of
Maintenance
Criteria for
initiating Maintenance
Condition
Assessment
Significance
& Techniques
needed
Results
Reactive
Repair actions are performed
after the failure
occurs and
people wait
until
equipment
fails, and then
maintenance
actions focused
to quickly
make possible
the availability
of equipment.
Fix it when it breaks
Unscheduled/ unplanned
Upon failure, work stoppage
to fix problem
immediately
Not usually
Large maintenance
budget
Unpredictable asset
availability
and
reliability
Preventive
In PM, maintenance
performed
before failure occurs,
for equipment
in which
downtime costs
more than
preventing
incipient
failure.
Schedule maintenance
Pre scheduled / pre planned
Prescribed based on failure
history or test
data.
To prevent
operation
problems that
lead to failure.
Not usually but
sometimes
manually collected
Periodic component
replacement/
repair.
Maintenance performed
more often
than may be necessary.
Assets often
taken off-line
time for
service.
Predictive
In PdM,
indicators
show the
requirement of
maintenance
actions to take. So it is a type
of maintenance
performed on the basis of
requirement of
machine.
Repair prior
to failure
when needed
Just in time
( planned)
Scheduled as
per need
Prescribed
based on
statistical
patterns in
operating
parameters.
To prevent
operation problems that
lead to failure or
reduced throughput.
Periodic
sample data
collection.
Monitoring
condition by
vibration,
heat,
alignment,
wear debris etc.
Maintenance
performed
when
necessary.
Better asset availability
and
reliability.
Condition Based
It is performed as per
requirement
and use
sophisticated
equipments to
detect signs of
imminent
failure. So
maintenance is performed
when need
arises.
Repair prior to failure
condition
based
Just in time ( planned)
Prescribed based on
statistical
patterns in
operating
parameters.
To prevent
operation
problems that lead to failure or
reduced
throughput
Continuous/
real time sensor
monitoring
and data
collection.
Monitoring
condition by vibration,
heat,
alignment,
wear debris
etc.
Maintenance performed
when
necessary.
Highest asset
availability
and
reliability.
It is an on-
line
monitoring system, and
generally
continuous.
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2.3.3 Select RCM strategy There are four components of RCM program which are,
• Reactive Maintenance
• Preventive Maintenance
• Predictive Maintenance
• Proactive Maintenance.
Predictive maintenance is an extension of preventive maintenance, but offers timely
failure detection of in-service machine, reduce failure severity and frequency, minimize
overall cost of maintenance, and improve operational safety. The selected maintenance
strategy is predictive maintenance in addition to preventive maintenance. It can be
implemented through two methods (Amik Garg et al., 2006);
1. Performance monitoring,
2. Monitoring through Diagnostic equipment.
As discussed above that, for critical components preventive maintenance is
insufficient to control failure, so any predictive maintenance technique is recommended.
There are many parameters which can be measured and analyzed to predict imminent failure
and monitor health of equipment. Monitoring through Diagnostic equipment enable us to
monitor;
• Machine vibration
• Wear debris analysis
• Infrared thermography
• Laser alignment
• Oil analysis
• Noise survey
Secondly, operating characteristics or performance parameters can help out in
detecting problems such as;
• Variation in Flow rates
• Pressure/temperature differences
• Comparison ratios
• Cycle efficiencies
• Variation in production rate
• Variation in product quality
• Efficiency, etc
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Fig 2 Flowchart of Selected Predictive Maintenance Techniques
2.3.4 Implementation of Predictive maintenanceThe Predictive maintenance can be implemented in three distinct stages;
1. Detection
2. Analysis
3. Correction
In initial phase, it involves a detailed survey of the plant and its equipment. Then
critical and non critical equipment is classified and an RCM strategy is selected which is
appropriate for improving reliability and availability of these equipment. In case of predictive
maintenance, parameters are selected to monitor health of machines. Acceptable condit
(limits) are set and to collect data to record and analyze data. Detection means identifying any
abnormality in collected data of a particular parameter. It involves measuring and trend
analysis at marked points on each machine on a regular (scheduled
find out the root cause of the abnormality detected. It is basically a diagnosis of machine
problem, so that corrective action can be taken. Corrective action can be easily planned to
keep machine downtime at an absolute minimum.
alarm about developing problems. The below flowchart illustrates each step clearly;
International Journal of Industrial Engineering Research and Development (IJIERD), ISSN 0976
6987(Online), Volume 5, Issue 1, January - February (2014), © IAEME
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Flowchart of Selected Predictive Maintenance Techniques
Implementation of Predictive maintenance can be implemented in three distinct stages;
In initial phase, it involves a detailed survey of the plant and its equipment. Then
critical equipment is classified and an RCM strategy is selected which is
appropriate for improving reliability and availability of these equipment. In case of predictive
maintenance, parameters are selected to monitor health of machines. Acceptable condit
(limits) are set and to collect data to record and analyze data. Detection means identifying any
abnormality in collected data of a particular parameter. It involves measuring and trend
analysis at marked points on each machine on a regular (scheduled) basis. Analysis helps to
find out the root cause of the abnormality detected. It is basically a diagnosis of machine
problem, so that corrective action can be taken. Corrective action can be easily planned to
keep machine downtime at an absolute minimum. Its implementation’s main objective is to
alarm about developing problems. The below flowchart illustrates each step clearly;
International Journal of Industrial Engineering Research and Development (IJIERD), ISSN 0976 –
February (2014), © IAEME
In initial phase, it involves a detailed survey of the plant and its equipment. Then
critical equipment is classified and an RCM strategy is selected which is
appropriate for improving reliability and availability of these equipment. In case of predictive
maintenance, parameters are selected to monitor health of machines. Acceptable conditions
(limits) are set and to collect data to record and analyze data. Detection means identifying any
abnormality in collected data of a particular parameter. It involves measuring and trend
) basis. Analysis helps to
find out the root cause of the abnormality detected. It is basically a diagnosis of machine
problem, so that corrective action can be taken. Corrective action can be easily planned to
Its implementation’s main objective is to
alarm about developing problems. The below flowchart illustrates each step clearly;
International Journal of Industrial Engineering Research and Development (IJIERD), ISSN 0976 –
6979(Print), ISSN 0976 – 6987(Online), Volume 5, Issue 1, January - February (2014), © IAEME
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Fig 3: Flowchart for Implementation of Predictive Maintenance
2.3.5 Selection of Vibration Analysis Vibration is the dominant characteristic which exists in almost all machines and is
said to be the heartbeat of all mechanical equipment. Its information allows analysts to
become aware of technical condition of a machine and to diagnose its ailments, especially in
case of rotating equipment such as: gearboxes, fans, shafts, motors, compressors, pumps,
mixers, driers. Simply measuring amplitude and frequency of vibration helps to detect
machine problem and its root cause. Aim of vibration monitoring is to collect data
automatically and transmit it to specialist for analysis so that an early identification and
correction of potential machinery problems is possible.
When machine vibration increases beyond its acceptable limits, the usual reason in
any machine are unbalance, misalignment, worn parts, looseness, etc.
CLASSIFYING EQUIPMENTS
SELECT PREDICTIVE MAINTENANCE
CRITICAL
EQUIPMENT SELECT PREVENTIVE
MAINTENANCE
SELECT PARAMETERS TO
MONITOR
SET ACCEPTABLE
CONDITION LIMITS
COLLECT DATA
TREND ANALYSIS OF
FAULT DETECTION
CONDITION ANALYSIS &
ROOT CAUSE FINDING
REMEDIAL ACTION
PLANT SURVEY
YES
NO
International Journal of Industrial Engineering Research and Development (IJIERD), ISSN 0976 –
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Vibration monitoring requires higher start up investment cost for instruments and skill
development of maintenance personnel, but it is in-service powerful information source for
detecting imminent failure and monitoring machine health. It is easy to record data and
transfer it to analyze, with portable and versatile instruments. It has accuracy to diagnose
problem and permits effective planning of corrective action, planned shutdown time, skilled
maintenance personnel and spare parts requirement. According to survey data of American
Society of Mechanical Engineers (ASME), upto 82 percent of malfunctions of the mechanical
equipment can be detected with the help of vibro-monitoring and vibro-diagnostic methods.
(Parida et al., 2000)
2.5 Summary In ABC Automobile Company, preventive maintenance system enables it to prevent
malfunctioning of critical equipment. In this system, condition monitoring of critical
equipment is performed through manually collected data on the basis of senses of sight,
smell, touch and hearing. For example the data of Paint booth fans just shows whether
abnormal noise exists or not. This system has limitation of actual parameter measurement and
authenticity of information.
Secondly it enables to alarm or indicate imminent failure and to take remedial action
before failure occurs. After the deep analysis with the help of RCM, it is concluded to follow
predictive maintenance system for critical equipment. In plant survey, equipment are
classified into critical and non critical categories and then proposed predictive maintenance
for critical components. For predictive maintenance, parameters are selected for each
machine, and to collect data and analyze. This analysis or trend data indicates imminent
failure and give alarms to take remedial action before failure occurs.
Predictive maintenance basically focuses on the future problem and helps to monitor
condition on-line. This on line condition monitoring helps to perform well planned
maintenance tasks and eliminates consequential losses. Through this system ABC
Automobile Company cannot perform unneeded maintenance and reduces overall
maintenance cost. To check the validity of the proposal a test case is taken of Paint Booth
process and vibration monitoring technique used on its fans to collect data to predict
imminent failure.
Test Case:
Step # 1 Equipment Selection The car paint process is important not only in aesthetic aspects of car but also it has
direct impact on the business. Car Paint quality cannot be compromised because it is an
integral feature of a business to generate repeated sales. The purpose of paint is to get
smooth, uniform and shiny coats which can withstand extreme conditions of sunlight, rain or
dust and tends to last long. So the paint booth process plays vital role to fulfill all
requirements of finishing process, as given below.
• Shiny and glamorous look,
• corrosion and rust prevention,
• Resistant to fading due to sun and ultraviolet rays,
In process of Painting and Drying Spray booth plays an important role where the
selected critical components are fans. In Painting and Drying Spray booth the vehicle is
painted through a spray gun with air channel, which works under low pressure, followed by
drying. The ceiling filter system derives air from outside of the facility, into the booth. Paint
International Journal of Industrial Engineering Research and Development (IJIERD), ISSN 0976
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stop filters hold paint particles which are decomposed from air. Spray booth contains diesel
burner and fan-motor units. A channel connection to units for air circul
installed on the facility floor.
The most important and critical function of a spray booth is managing its airflow
maintaining uniform velocity in unidirectional layers. The managed airflow results in two
advantages,
• Maximum efficiency of the paint sprayed in the Paint booth,
• And improved finish quality through directing overspray away from the painted
finish.
Air supply house supplies air to the booth after conditioning and filtering, minimizing
temperature variations and removing particulates that compromise finish quality.
Intake air moving across the painting operation conveys the overspray into the water
curtain and the water wash apparatus, which then works to move the water in such a way as
to trap and separate the particulate from the recycling water.
Process flow of paint booth is shown in fig 5, with sequence of operation and
sequence of equipment.
Fig 5
International Journal of Industrial Engineering Research and Development (IJIERD), ISSN 0976
6987(Online), Volume 5, Issue 1, January - February (2014), © IAEME
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stop filters hold paint particles which are decomposed from air. Spray booth contains diesel
motor units. A channel connection to units for air circulation is executed and
The most important and critical function of a spray booth is managing its airflow
maintaining uniform velocity in unidirectional layers. The managed airflow results in two
efficiency of the paint sprayed in the Paint booth,
And improved finish quality through directing overspray away from the painted
Air supply house supplies air to the booth after conditioning and filtering, minimizing
removing particulates that compromise finish quality.
Intake air moving across the painting operation conveys the overspray into the water
curtain and the water wash apparatus, which then works to move the water in such a way as
articulate from the recycling water.
Process flow of paint booth is shown in fig 5, with sequence of operation and
Fig 5: Process flow of paint booth
International Journal of Industrial Engineering Research and Development (IJIERD), ISSN 0976 –
February (2014), © IAEME
stop filters hold paint particles which are decomposed from air. Spray booth contains diesel
ation is executed and
The most important and critical function of a spray booth is managing its airflow
maintaining uniform velocity in unidirectional layers. The managed airflow results in two
And improved finish quality through directing overspray away from the painted
Air supply house supplies air to the booth after conditioning and filtering, minimizing
removing particulates that compromise finish quality.
Intake air moving across the painting operation conveys the overspray into the water
curtain and the water wash apparatus, which then works to move the water in such a way as
Process flow of paint booth is shown in fig 5, with sequence of operation and
International Journal of Industrial Engineering Research and Development (IJIERD), ISSN 0976 –
6979(Print), ISSN 0976 – 6987(Online), Volume 5, Issue 1, January - February (2014), © IAEME
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Step # 2 RCM Process Seven Questions & Answers
1. What are the functions and associated desired standards of performance of the asset in its
present operating context (functions)?
Delivery of air into the booth or circulation of it is provided by fans, having the capacity
of 360 m³ / min. In this unit air is delivered to the booth after being filtered by a pre-filter.
Additionally output air is controlled by a damper in the output air channel.
1. In what ways can it fail to fulfill its functions (functional failures)?
Table 3: Functional failures
Function Function Failure
Delivery of the air into the booth or
circulation of it is provided by fans while
meeting all quality, health, safety, and
environmental standards.
1. Unable to rotate at 1460 rpm
2. Unable to meet quality standards
3. Unable to meet health, safety, and
environmental standards.
2. What causes each functional failure (failure modes)?
Vibration is due to the repeating forces in machines which are mostly due to the rotation
of imbalanced and misaligned parts and may be due to the following,
• Looseness
• Contamination
• Oil condition
• Wear and tear
• Defective bearing
3. What happens when each failure occurs (failure effects)?
Failure may have following effects;
• Broken, deformed, corroded or dirty fan blades.
• Fan may trip
• Machine unavailability
• Unnecessary maintenance at predetermined schedules to adjust and replace parts
regardless of whether or not the machines are malfunctioning
• Quality problems when machine is running, which apparently seem functioning
normally, but actually running into trouble and may have yielded losses rework costs,
or worse still, warranty returns by customers.
4. In what way does each failure matter (failure consequences)?
Failure may have following effects;
• High Power Consumption, as machine that is vibrating consumes more power.
• Cost of lost production
• Cost of emergency spares procurement
• Cost of maintenance and additional overheads
• Delayed Shipment resulting in customer dissatisfaction
• Accumulation of unfinished goods or WIP (work in process)
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• Bad company image will be associated with shipment delays and poor quality
• Occupational hazards and human discomfort
5. What should be done to predict or prevent each failure (proactive tasks and task
intervals)?
Monitoring the vibration characteristics of a machine gives us an understanding of the
‘health’ condition of the machine. We can use this information to detect problems that might
be developing. Operating a machine until it breaks down might be acceptable if the machine
was a ‘disposable’ one. Most machines, however, are not ‘disposable’ due to their cost.
6. What should be done if a suitable proactive task cannot be found (default actions)?
Default actions are may be routine preventive maintenance at predetermined
schedules and cleaning of fan blades or allowed to breakdown.
This RCM seven Question process helps to determine the causes of system failures
and develop activities targeted to prevent them. The questions are designed to focus on
maintaining the required functions of the system and help to conclude proactive maintenance
strategy.
The answers of first four questions, which are related to functional failure, causes and
effects, are recorded in RCM information sheet as shown in table 4.
In table 5 answers of remaining question is recorded which is decision worksheet.
Decision worksheet is recorded with the help of answering question in RCM decision
diagram related to failure consequences, preventive tasks and default actions as shown in
Fig 6.
Table 4: RCM information worksheet
RCM information Worksheet Unit: Paint Booth Sr.
no Function
Component: Fans
Functional
failure Failure mode Failure effect
1) Delivery of
the air into the
booth or
circulation of it
is provided by
fans while
meeting all
quality, health,
safety, and
environmental
standards.
A) Unable to
rotate at 1460
rpm
Unable to meet
quality standards
Unable to meet
health, safety,
and
environmental
standards.
a) Looseness
b) Contamination
c) Oil condition
d) Wear and tear
e) Defective
bearing
Broken, deformed, corroded or
dirty fan blades.
Fan may trip
Machine. Unavailability.
Unnecessary maintenance at
predetermined schedules to
adjust and replace parts
regardless of whether or not the
machines are malfunctioning.
Quality problems when
machine is running, it appears
to be functioning normally, but
into trouble and may have
yielded losses, rework costs, or
worse still, warranty returns by
customers.
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Fig 6: RCM decision diagram (V.S Deshpande et al., 2003)
Fig 7: Failure consequences summary (V.S Deshpande et al., 2003)
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Table 5: RCM decision worksheet
RCM decision Worksheet Unit: Paint Booth
Component: Fans
Information
reference Consequence
evaluation
H1 H2 H3 Default
action
Proposed Task
S1 S2 S3
O1 O2 O3
F FF FM H S E O N1 N2 N3 H4 H5 S4 1 A
(a) Y N N Y N Y - - - - Schedule restoration
(b) N N N Y Y - - - - - Schedule On condition
(c) N N N Y Y - - - - - Schedule On condition
(d) N N N Y Y - - - - - Schedule On condition
(e) N N N Y N N Y - - - Schedule discard
Legends :
Step # 3 Selecting RCM Strategy In process of paint booth, unscheduled breakdown of critical components like fans
can cause production and other consequential losses. One of the selected critical components
is fans, in which buff deposit may cause other defects like wear, imbalance, etc. Its managed
airflow enables to get maximum efficiency of the paint sprayed while directing overspray
away from the painted finish. Predictive maintenance through vibration monitoring is
selected to keep the function preserved. The parameter of velocity is selected to monitor such
that must it be evenly maintained and balanced at 0.5mm/sec to perform proper function.
Y= Yes N= No F= Failure
FF=
Functional failure
FM= Failure Mode
H= Hidden
failure consequences
S= safety consequences
E=
Environmental consequences
O= Operational
consequences
N =Non Operational
consequences
H1/S1/O1/N1 On condition
Task
H2/S2/O2/N2
Scheduled restoration
Task
H3/S3/O3/N3
Discard Task
H4= Default
action
H5= Default
action
S4= Default
action
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Fig 8: Flowchart for Implementation of Predictive Maintenance
PAINT BOOTH
SELECTED
SELECT PREDICTIVE
MAINTENANCE
FANS
SELECTED AS
CRITICAL
SELECT PREVENTIVE
MAINTENANCE
VIBRATION MONITORING
SELECTED
ACCEPTABLE LIMIT 0.5
mm/sec
COLLECT DATA
TREND ANALYSIS OF
FAULT DETECTION
CONDITION ANALYSIS &
ROOT CAUSE FINDING
REMEDIAL ACTION
PLANT SURVEY
YES
NO
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The data collected (Table 6 and Fig 9) is plotted in given below graph, and analysis
performed on these reading revealed operation at alarm level.
Table 6: Vibration readings before repair
S.no Date Amplitude Unit Alarm Level
1 15-Oct-11 0.435 m/sec 0.55
2 16-Oct-11 0.57 m/sec 0.55
3 17-Oct-11 0.56 m/sec 0.55
4 18-Oct-11 0.55 m/sec 0.55
5 19-Oct-11 0.59 m/sec 0.55
6 20-Oct-11 0.43 m/sec 0.55
7 21-Oct-11 0.55 m/sec 0.55
8 22-Oct-11 0.58 m/sec 0.55
9 23-Oct-11 0.61 m/sec 0.55
10 24-Oct-11 0.54 m/sec 0.55
Fig 9: Equipment Vibration Monitoring Trend report before repair
After trend analysis for default detection, it is found that;
• buff deposits on fan blades,
• unbalancing,
• bearings in deteriorated condition and,
• oil condition has to be inspected,
So for, the remedial action of cleaning has been performed to remove buff deposits
from blades and deteriorated bearings were replaced. Fan was then rotated and found
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
TREND DATA
TREND DATA
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dynamic unbalanced, so in-situ balancing performed to restore proper functioning. It is
dynamically balanced at 1460 rpm and the vibration level reduced from 0.61 mm/sec to 0.5
mm/sec, as shown in graph (Table 7 and Fig 10) below.
Table 7: Vibration readings after repair
S.no Date Amplitude Unit Alarm Level
1 25-Oct-11 0.5 m/sec 0.55
2 26-Oct-11 0.51 m/sec 0.55
3 27-Oct-11 0.49 m/sec 0.55
4 28-Oct-11 0.5 m/sec 0.55
5 29-Oct-11 0.52 m/sec 0.55
6 30-Oct-11 0.44 m/sec 0.55
7 31-Oct-11 0.46 m/sec 0.55
8 1-Nov-11 0.5 m/sec 0.55
9 2-Nov-11 0.5 m/sec 0.55
10 3-Nov-11 0.49 m/sec 0.55
Fig 10: Equipment Vibration Monitoring Trend report after repair
In this way, vibration monitoring data provided very detailed assessment of fault
causes, and selected repair action performed as per need of equipment condition. Since then,
the fans are running smoothly and uninterruptedly.
CONCLUSIONS AND PERSPECTIVES
The paper highlights application of predictive maintenance strategy and the benefits
of its implementation for the equipment at ABC Automobile Company, instead of preventive
maintenance. This study focuses on rotating equipment (e.g. motors, pumps, conveyors,
compressors), where vibration monitoring can be implemented through RCM.
0.4
0.42
0.44
0.46
0.48
0.5
0.52
0.54
TREND DATA
TREND DATA
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The comprehensive literature review is presented of maintenance, its types and the
interfacing topics. The qualitative data is collected and analyzed with determining the
effectiveness of existing maintenance strategy. Predictive maintenance is proposed in
addition to preventive maintenance, and its previewed benefits compared. To preserve
function of equipment, RCM seven question analyses performed in test case and vibration
monitoring data is collected for fan of paint booth. That data trend is analyzed and used to
identify causes of imminent damage. So, equipment is repaired before failure and reliability
is increased by eliminating root causes.
In this way, RCM helps to plan scheduled maintenance and scarce economic
resources on critical equipment having high risk of failure. The paper reveals that the ABC
Automobile Company Ltd can achieve enhanced manufacturing performance leading to
competitive advantage with successful RCM implementation through predictive maintenance.
Due to limited resources and time, the paper showed only test case of fan of paint
booth, but in case it will implemented on all critical equipment then it will further clarify the
differences and benefits of predictive maintenance strategy over other. So, it is strongly
recommended to implement this proposal and analyze the situation differences to explore
effective Reliability Centered Maintenance.
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