Unit 2 Maintenance Engg

Unit 2 - Maintenance Categories
Preventive Maintenance:
Preventive maintenance (or preventative maintenance) is maintenance that is regularly performed
on a piece of equipment to lessen the likelihood of it failing. It is performed while the equipment
is still working so that it does not break down unexpectedly. In terms of the complexity of this
maintenance strategy, it falls between reactive (or run-to-failure) maintenance and predictive
maintenance.
Types of preventive maintenance

Preventive maintenance can be scheduled on a time or usage based trigger. Let’s look at an
example for each.
Time-based preventive maintenance
A typical example of a time-based preventive maintenance trigger is a regular inspection on a
critical piece of equipment that would severely impact production in the event of a breakdown.
Usage-based preventive maintenance
Usage-based triggers fire after a certain amount of kilometres, hours, or production cycles. An
example of this trigger is a motor-vehicle which might be scheduled for service every 10,000km.
Preventive Maintenance Workflow

The graphic below outlines the predictive maintenance workflow from start to finish.
How preventive maintenance decreases downtime?

Think about it in simple terms such as with your car. Oil changes and regular servicing are part of a
preventive maintenance schedule that ensures your car runs properly and without unexpected failure.
If you ignore that maintenance schedule and miss service intervals, your car will depreciate in value
and utility. The same goes for machinery in manufacturing plants and equipment in facilities.
With a PM schedule in place, maintenance managers can decrease downtime. This schedule is
usually automated with a CMMS that comes with PM scheduling software. However, managers are
always cautious of over-maintaining assets. There’s a point where preventive maintenance starts
costing too much in relation to the amount of downtime it prevents.
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The optimal amount of preventive maintenance occurs when the cost of corrective and preventive
maintenance meet
Examples of preventive maintenance
Some aspects of a solid preventive maintenance program are obvious. Production line equipment
should be suitably maintained to prevent breakdown, and infrastructure elements such as heating,
ventilation, and air conditioning (HVAC) should be routinely inspected, cleaned, and updated as
required. However, there may be other systems that also need routine maintenance to prevent failure.
How about your water systems? Do you have appropriate filtration? Are you running warm water
systems that may be a breeding area for serious bacterial infections such as Legionnaires Disease?
How about your electrical systems and the need to ensure that they not only comply with legislation
but do not degrade over time? Doors, stairways, lighting, and flooring all need periodic inspection
and maintenance, too.
The list of what needs to be included in your preventive maintenance plan can be bewildering, but
there are certain guidelines that give you at least a basis to conform too. The American National
Standards Institute (ANSI) carries a lot of information on preventive maintenance and is a good place
to start if you are unsure as to the extent of the program that you need.
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Note: Preventive maintenance checklist example
Benefits of preventive maintenance

There are more benefits of implementing a preventive maintenance program than merely reducing
the amount of unplanned downtime. Other benefits include:
• Extension of asset lifetime
• Increased safety and reduced risk of injury
• Optimized maintenance planning and resource allocation
• Less expensive corrective repairs
• Better margins and profits due to less downtime
Perhaps the greatest benefit is increased safety, especially for a company that owns heavy machinery.
The price of employee safety is never too high and organizations such as the Occupational Health
and Safety Administration (OHSA) rigorously enforce government policy.
Advantages of preventive maintenance
Advantages compared with less complex strategies

Planning is the biggest advantage of a preventive maintenance program over less complex strategies.
Unplanned, reactive maintenance has many overhead costs that can be avoided during the planning
process. The cost of unplanned maintenance includes lost production, higher costs for parts and
shipping, as well as time lost responding to emergencies and diagnosing faults while equipment is
not working. Unplanned maintenance typically costs three to nine times more than planned
maintenance. When maintenance is planned, each of these costs can be reduced. Equipment can be
shut down to coincide with production downtime. Prior to the shutdown, any required parts, supplies
and personnel can be gathered to minimize the time taken for a repair. These measures decrease the
total cost of the maintenance. Safety is also improved because equipment breaks down less often than
in less complex strategies.
Advantages compared with more complex strategies

A preventive maintenance program does not require condition-based monitoring. This eliminates the
need (and cost) to conduct and interpret condition monitoring data and act on the results of that
interpretation. It also eliminates the need to own and use condition monitoring equipment.
Disadvantages of preventive maintenance
Disadvantages compared with less complex strategies

Unlike reactive maintenance, preventive maintenance requires maintenance planning. This requires
an investment in time and resources that are not required with less complex maintenance strategies.
Maintenance may occur too often with a preventive maintenance program. Unless, and until the
maintenance frequencies are optimized for minimum maintenance, too much or too little preventive
maintenance will occur.
Disadvantages compared with more complex strategies
The frequency of preventive maintenance is most likely to be too high. This frequency can be
lowered, without sacrificing reliability when condition monitoring and analysis is used. The decrease
in maintenance frequency is offset by the additional costs associated with conducting the condition
monitoring.
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Conclusion
Preventive maintenance is often seen as an overhead cost that is difficult to justify. But it takes just
one period of downtime or a single notifiable accident to demonstrate how important it is to
undertake a program of forward-looking maintenance.
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What is predictive maintenance?
Predictive maintenance
Predictive maintenance is a technique to predict the future failure point of a machine component,
so that the component can be replaced, based on a plan, just before it fails. Thus, equipment
downtime is minimized and the component lifetime is maximized.
Predictive maintenance (PdM) is a type of condition-based maintenance that monitors the

condition of assets using sensor devices. These sensor devices supply data in real-time, which is
used to predict when the asset will require maintenance and prevent equipment failure.
The use of predictive maintenance is to establish, firstly, a historical perspective on the relation
between the selected variable and the component life. This is accomplished by taking readings
(for example, the vibration of a bearing) at regular intervals until the component fails. The figure
shows a typical curve which results from plotting the variable (vibration) against time. As the
curve suggests, subsequent bearings should be replaced when the vibration reaches 1.25 in / sec
(31.75 mm / sec). Manufacturers of instrumentation and software for predictive maintenance
may recommend ranges and values to replace the components of most equipment; this historical
analysis makes it unnecessary in most applications.
How predictive maintenance compares to other options

Predictive maintenance (PdM) is the most advanced type of maintenance currently available.
With time-based maintenance, organizations run the risk of performing too much maintenance or
not enough. And with reactive maintenance, maintenance is performed when needed, but at the
cost of unscheduled downtime. Predictive maintenance solves these issues. Maintenance is only
scheduled when specific conditions are met and before the asset breaks down.
A brief history of predictive maintenance

Organizations started using predictive maintenance tools around the start of the twenty first
century. To monitor conditions of assets, organizations used a periodic or offline approach.
A study that documents three PdM case studies from 2001 states: “The vibration measurements
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are taken periodically—one time per month in general—and vibration is monitored by
comparing previous measurements to new ones.”
Today, a continuous or online approach is used to monitor conditions of assets. Remote
monitoring is also possible by connecting an IoT sensor device to maintenance software. When
specific conditions are met, a work order for an inspection is triggered.
How does predictive maintenance work?

The first step in practicing predictive maintenance is establishing baselines. You need to monitor
assets’ conditional baselines and collect data before installing sensors. That way, when you begin
to collect conditional data, there is a “control” to compare any abnormalities to. From there, it’s
simple - any time a piece of equipment performs outside of normal parameters, the sensors
trigger your predictive maintenance protocol. Typically, a work order is generated in your
CMMS and assigned to technicians so they can perform any required repairs to address the
anomaly
Predictive maintenance workflow

The graphic below outlines the predictive maintenance workflow from start to finish. The
ultimate goal with predictive maintenance is to catch breakdowns before they happen by
monitoring equipment conditions.
Note: Predictive maintenance workflow exmaple

How to implement predictive maintenance?
Before predictive maintenance is implemented on the facility floor, ROI cases are presented to
management. Maintenance staff and machine operators are also trained with how to use the PdM
technology. After this happens, true implementation begins.
1. Establish baselines
The maintenance team establishes acceptable condition limits for assets that will have sensors.
2. Install Internet of Things (IoT) devices
The relevant sensor is affixed to the asset. For instance, a vibration meter is affixed to a
mechanical asset with gears and a temperature sensor is attached to a boiler.
3. Connect devices to software
The IoT device is connected to a CMMS or remote dashboard where data is collected and
analyzed.
4. Schedule maintenance
Inspections are automatically triggered by a CMMS when the condition limit is exceeded or the
person monitoring the dashboard schedules the inspection manually.
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Types of predictive maintenance
To evaluate equipment condition, predictive maintenance utilizes nondestructive
testing technologies such as infrared, acoustic (partial discharge and airborne ultrasonic), corona
detection, vibration analysis, sound level measurements, oil analysis, and other specific online
tests. A new approach in this area is to utilize measurements on the actual equipment in
combination with measurement of process performance, measured by other devices, to trigger
equipment maintenance. This is primarily available in collaborative process automation systems
(CPAS). Site measurements are often supported by wireless sensor networks to reduce the wiring
cost.
Vibrational analysis
Machine Speed: High | Machine Type: Mechanical | Cost: Medium
This is the go-to type of analysis for predictive maintenance inside manufacturing plants with
high-rotating machinery. Because it’s been around longer than other types of condition
monitoring, it’s relatively cost-effective. In addition to detecting looseness like in the example
above, vibrational analysis can also discover imbalance, misalignment, and bearing wear.
Note: Using vibration analysis in predictive maintenance on a motor
Acoustical analysis (sonic)

Machine Speed: Low, High | Machine Type: Mechanical | Cost: Low
This type of analysis requires less money to implement and is used for low- and high-rotating
machinery. It’s particularly popular among lubrication technicians.
According to an article by Machinery Lubrication, “Acoustic analysis is similar to vibration

analysis; however, its focus is not to detect causes for rotating equipment failure by measuring
and monitoring vibrations at discrete frequencies and recording data for trending purposes.
Instead, acoustic bearing analysis is intended for the lubrication technician and focuses on
proactive lubrication measures.”
Acoustical analysis (ultrasonic)
Machine Speed: Low, High | Machine Type: Mechanical, Electrical | Cost: High
While sonic acoustical analysis borders on the line of proactive and predictive maintenance,
ultrasonic acoustical analysis is solely used for predictive maintenance efforts. And because it
can identify sounds related to machine friction and stress in the ultrasonic range, it’s used for
electrical equipment that emit subtler sounds as well as mechanical equipment. It’s argued that
this type of analysis predicts imminent breakdowns better than vibration or oil analysis.
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Infrared analysis
Machine Speed: Low, High | Machine Type: Mechanical, Electrical | Cost: Low
This type of analysis is not dependent on an asset’s rotational speed or loudness. Therefore it’s
suitable for many different types of assets. When temperature is a good indicator of potential
issues, infrared analysis is the most cost-effective tool for predictive maintenance. It’s often used
to identify problems related to cooling, air flow, and even motor stress.
Model Based Condition Monitoring

The use of Model Based Condition Monitoring for predictive maintenance programs is
becoming increasingly popular over time. This method involves spectral analysis on the motor’s
current and voltage signals and then compares the measured parameters to a known and learned
model of the motor to diagnose various electrical and mechanical anomalies. This process of
"model based" condition monitoring was originally designed and used on NASA’s space shuttle
to monitor and detect developing faults in the space shuttle’s main engine. It allows for the
automation of data collection and analysis tasks, providing round the clock condition monitoring
and warnings about faults as they develop.
Example of predictive maintenance

A centrifugal pump motor in a coal preparation plant is a vital asset for day-to-day operations.
To prevent unscheduled downtime, the maintenance team decides to use predictive maintenance
technology. Because it’s a large piece of mechanical equipment that performs heavy rotations,
the obvious choice is to monitor vibrations with vibration meters.
The team attaches a vibration meter close to the pump’s inner bearing and establishes a normal
baseline measurement, visualized through a waveform graph (below, left). A few months later,
the vibration meter identifies a spike in acceleration (below, right). The maintenance team
reviews this new data remotely and schedules an inspection. The technician who performs the
inspection finds a loose ball-bearing and repairs it.
Moving forward, the team connects the vibration meter to its CMMS. Now, when the same spike
is identified, a fault with the ball-bearing is predicted and a work order is automatically triggered
to perform the repair.
Note: This example is inspired from a real use case documented in this study.
The benefits of predictive maintenance
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Predictive maintenance stands to improve your maintenance and reliability program as a whole.
By using technology and best practices to streamline processes and increase productivity. A few
of the top benefits of predictive maintenance are:
Increasing asset uptime by 30% and reducing unexpected failures by 55%.
Streamlining maintenance costs through reduced labor, equipment, and inventory costs.
Improving safety.
The ROI of predictive maintenance

According to a paper by the US Department of Energy, “a well-orchestrated predictive
maintenance program will all but eliminate catastrophic equipment failures.” Compared to
a preventive maintenance program, cost savings are 8 to 12 percent higher; and compared to a
reactive maintenance program, cost savings range from 30 to 40 percent.
Other numbers stated by the Department of Energy include:
Return on investment: 10 times
Reduction in maintenance costs: 25% to 30%
Elimination of breakdowns: 70% to 75%
Reduction in downtime: 35% to 45%
Increase in production: 20% to 25%
Applications (by industry)

Railway
• Detect problems before they cause downtime for linear, fixed and mobile assets.
• Improving safety and track void detection through a new vehicle cab-based monitoring
system
• Siemens Tracksure track monitoring system is able to identify voids underneath track from
the acceleration measured in the vehicle cab.
• Can also identify the type of track asset that the void is located under and provide an
indication of the severity of the void
• Health Monitoring of point Machines (devices used to operate railway turnouts) can aid in
detecting early symptoms of degradation prior to failure.
Manufacturing
• Early fault detection and diagnosis in the manufacturing industry.
• Manufacturers increasingly collect big data from Internet of Things (IoT) sensors in their
factories and products and using different algorithms for the collected data to detect warning
signs of expensive failures before they occur.
• Manufacturing industry: predict equipment failures can be easily found out using big data.
Oil and Gas
• Oil and gas companies often lack visibility into the condition of their equipment, especially
in remote offshore and deep-water locations.
• Big data can provide insight to oil and gas companies, this way equipment failures and the
optimal lifetime of the system and components can be analyzed and predicted.[
• Considerable work has been done in the area of health monitoring and fault diagnosis of
rotating machinery equipment in manufacturing industry.
Battery
• Detecting underlying degradation and predicting how soon a battery will reach a level of
unsatisfactory performance.[31]
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• Health assessment of batteries in electric vehicles for accurate quantification of the State of
Health (SOH) and its subsequent impact on vehicle mobility
Conclusion
Predictive maintenance is not for every organization, especially those that have yet to implement
planned maintenance activities. But for larger organizations that have outgrown traditional PMs
and have additional budget, predictive maintenance can provide an ROI that turns the
maintenance department into a source of cost-savings and higher profits.
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Condition-based maintenance (CBM)
Definition
Condition Based Monitoring (CBM) is a type of predictive maintenance that involves using
sensors to measure the status of an asset over time while it is in operation. The data collected can
be used to establish trends, predict failure, and calculate remaining life of an asset.[1] With CBM,
maintenance is only performed when the data shows that performance is decreasing or a failure
is likely
Condition-based maintenance (CBM) is a maintenance strategy that monitors the actual

condition of an asset to decide what maintenance needs to be done. CBM dictates that
maintenance should only be performed when certain indicators show signs of decreasing
performance or upcoming failure. Checking a machine for these indicators may include non-
invasive measurements, visual inspection, performance data and scheduled tests. Condition data
can then be gathered at certain intervals, or continuously (as is done when a machine has internal
sensors). Condition-based maintenance can be applied to mission critical and non-mission
critical assets.
Unlike in planned maintenance (PM), where maintenance is performed based upon predefined
scheduled intervals, condition-based maintenance is performed only after a decrease in the
condition of the equipment has been observed. Compared with preventive maintenance, this
increases the time between maintenance repairs, because maintenance is done on an as-needed
basis.
What’s the goal of condition-based maintenance?

The goal of condition based maintenance is to monitor and spot upcoming equipment failure so
maintenance can be proactively scheduled when it is needed – and not before. Asset conditions
need to trigger maintenance within a long enough time periods before failure, so work can be
finished before the asset fails or performance falls below the optimal level.
Example of condition-based maintenance

Motor vehicles come with a manufacturer-recommended interval for oil replacements. These
intervals are based on manufacturers’ analysis, years of performance data and experience.
However, this interval is based on an average or best guess rather than the actual condition of the
oil in any specific vehicle. The idea behind condition based maintenance is to replace the oil only
when a replacement is needed, and not on a predetermined schedule.
In the example of industrial equipment, oil analysis can perform an additional function too. By
looking at the type, size and shape of the metal particulates that are suspended in the oil, the
health of the equipment it is lubricating can also be determined.
Condition monitoring technology

The following list includes the main condition monitoring techniques applied in the industrial
and transportation sectors:
• Condition Monitoring Overview
• Vibration analysis and diagnostics
• Lubricant analysis
• Acoustic emission
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• Infrared thermography
• Ultrasound
• Oil Condition Sensors
• Motor condition monitoring and motor current signature analysis (MCSA)
• Model-based voltage and current systems (MBVI systems)
Most CM technologies are being standardized by ISO and ASTM.
Types of condition based maintenance

There are various types of condition-based monitoring techniques. Here are a few common
examples:
• Vibration analysis: Vibration Monitoring is a form of condition based monitoring that
involves listening to vibrations in an operating piece of equipment in order to determine
whether abnormal vibration patterns exist. Vibration monitoring is an important part of
effective asset integrity management, because changes in vibration levels can be indicative of
advanced wear and a number of other problems, including equipment coming loose from
mountings or malfunctioning parts. Rotating equipment such as compressors, pumps and
motors all exhibit a certain degree of vibration. As they degrade, or fall out of alignment, the
amount of vibration increases. Vibration sensors can be used to detect when this becomes
excessive. Information gathered while monitoring for vibration inconsistencies can be used
while planning predictive maintenance activities.
• Infrared: IR cameras can be used to detect high-temperature conditions in energized

equipment
• Ultrasonic: Detection of deep subsurface defects such as boat hull corrosion
• Acoustic: Used to detect gas, liquid or vacuum leaks
• Oil analysis: Measures the number and size of particles in a sample to determine asset wear
• Electrical: Motor current readings using clamp on ammeters
• Operational performance: Sensors throughout a system measure pressure, temperature,
flow etc.
• Often visual inspections are considered to form an underlying component of condition

monitoring, however this is only true if the inspection results can be measured or critiqued
against a documented set of guidelines. For these inspections to be considered condition
monitoring, the results and the conditions at the time of observation must be collated to allow
for comparative analysis against the previous and future measurements. The act of simply
visually inspecting a section of pipework for the presence of cracks or leaks cannot be
considered condition monitoring unless quantifiable parameters exist to support the
inspection and a relative comparison is made against previous inspections. An act
performed in isolation to previous inspections is considered a Condition Assessment,
Condition Monitoring activities require that analysis is made comparative to previous data
and reports the trending of that comparison.
• Slight temperature variations across a surface can be discovered with visual inspection
and non-destructive testing with thermography. Heat is indicative of failing components,
especially degrading electrical contacts and terminations. Thermography can also be
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successfully applied to high-speed bearings, fluid couplings, conveyor rollers, and storage
tank internal build-up.
• A scanning electron microscope can take an image of a carefully taken sample of debris
suspended in lubricating oil (taken from filters or magnetic chip detectors). Instruments then
reveal the elements contained, their proportions, size and morphology. Using this method,
the site, the mechanical failure mechanism and the time to eventual failure may be
determined. This is called WDA - Wear Debris Analysis.
• Spectrographic oil analysis that tests the chemical composition of the oil can be used to
predict failure modes. For example, a high silicon and aluminium content indicates
contamination of dirt or grit (aluminium silicates) etc., and high iron levels indicate wearing
components. Individually, elements give fair indications, but when used together they can
very accurately determine failure modes e.g. for internal combustion engines, the presence of
iron (liner), aluminium (piston) and chrome (rings) would indicate upper cylinder wear.
• Ultrasound can be used for high-speed and slow-speed mechanical applications and for
high-pressure fluid situations. Digital ultrasonic meters measure high frequency signals from
bearings and display the result as a dBuV (decibels per microvolt) value. This value is
trended over time and used to predict increases in friction, rubbing, impacting, and other
bearing defects. The dBuV value is also used to predict proper intervals for re-lubrication.
Ultrasound monitoring, if done properly, proves out to be a great companion technology for
vibration analysis.
Headphones allow humans to listen to ultrasound as well. A high pitched 'buzzing sound'
in bearings indicates flaws in the contact surfaces, and when partial blockages occur in
high pressure fluids the orifice will cause a large amount of ultrasonic noise. Ultrasound
is used in the Shock Pulse Method[18] of condition monitoring.
• Performance analysis, where the physical efficiency, performance, or condition is found by

comparing actual parameters against an ideal model. Deterioration is typically the cause of
difference in the readings. After motors, centrifugal pumps are arguably the most common
machines. Condition monitoring by a simple head-flow test near duty point using repeatable
measurements has long been used but could be more widely adopted. An extension of this
method can be used to calculate the best time to overhaul a pump based on balancing the cost
of overhaul against the increasing energy consumption that occurs as a pump wears. Aviation
gas turbines are also commonly monitored using performance analysis techniques with the
original equipment manufacturers such as Rolls-Royce plc routinely monitoring whole fleets
of aircraft engines under Long Term Service Agreements (LTSAs) or Total Care packages.
• Wear Debris Detection Sensors are capable of detecting ferrous and non-ferrous wear
particles within the lubrication oil giving considerable information about the condition of the
measured machinery. By creating and monitoring a trend of what debris is being generated it
is possible to detect faults prior to catastrophic failure of rotating equipment such as
gearbox's, turbines, etc.
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The Criticality Index
The Criticality Index is often used to determine the degree on condition monitoring on a given
machine taking into account the machines purpose, redundancy (i.e. if the machine fails, is there
a standby machine which can take over), cost of repair, downtime impacts, health, safety and
environment issues and a number of other key factors. The criticality index puts all machines
into one of three categories:
1. Critical machinery - Machines that are vital to the plant or process and without which
the plant or process cannot function. Machines in this category include the steam or gas
turbines in a power plant, crude oil export pumps on an oil rig or the cracker in an oil
refinery. With critical machinery being at the heart of the process it is seen to require full
on-line condition monitoring to continually record as much data from the machine as
possible regardless of cost and is often specified by the plant insurance. Measurements
such as loads, pressures, temperatures, casing vibration and displacement, shaft axial and
radial displacement, speed and differential expansion are taken where possible. These
values are often fed back into a machinery management software package which is
capable of trending the historical data and providing the operators with information such
as performance data and even predict faults and provide diagnosis of failures before they
happen.
2. Essential machinery - Units that are a key part of the process, but if there is a failure, the
process still continues. Redundant units (if available) fall into this realm. Testing and
control of these units is also essential to maintain alternative plans should critical
machinery fail.
3. General purpose or balance of plant machines - These are the machines that make up
the remainder of the plant and normally monitored using a handheld data collector as
mentioned previously to periodically create a picture of the health of the machine.
Challenges of condition-based maintenance

• Condition-based maintenance requires an investment in measuring equipment and staff up-
skilling so the initial costs of implementation can be high.
• CBM introduces new maintenance techniques, which can be difficult to implement due to
resistance within an organization.
• Older equipment can be difficult to retrofit with sensors and monitoring equipment, or can be
difficult to access during production to spot measure.
• With CBM in place, it still requires competence to turn performance information from a
system into actionable proactive maintenance items.
Advantages
• CBM is performed while the asset is working, which lessens the chances of disruption to
normal operations
• Reduces the cost of asset failures
• Improves equipment reliability
• Minimizes unscheduled downtime due to catastrophic failure
• Minimizes time spent on maintenance
• Minimizes overtime costs by scheduling the activities
• Minimizes requirement for emergency spare parts
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• Optimizes maintenance intervals (more optimal than manufacturer recommendations)
• Improves worker safety
• Reduces the chances of collateral damage to the system
Disadvantages
This method has some limitations as well though. The tools used to monitor equipment for CBM
can be expensive to install. Employees must be trained to use CBM technology effectively,
which can cost time and money. Furthermore, the sensors employed might not work in harsher
operating environments and can have trouble detecting fatigue damage
• Condition monitoring test equipment is expensive to install, and databases cost money to
analyze
• Cost to train staff–you need a knowledgeable professional to analyze the data and perform
the work
• Fatigue or uniform wear failures are not easily detected with CBM measurements
• Condition sensors may not survive in the operating environment
• May require asset modifications to retrofit the system with sensors
• Unpredictable maintenance periods
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Corrective maintenance
Corrective maintenance is a maintenance task performed to identify, isolate, and rectify a fault
so that the failed equipment, machine, or system can be restored to an operational condition
within the tolerances or limits established for in-service operations.
Corrective maintenance is any task that corrects a problem with an asset and returns it to proper
working order. Corrective maintenance tasks can be Both planned and unplanned.
There are three situations when corrective maintenance occurs:
1. When an issue is detected through condition monitoring
2. When a routine inspection uncovers a potential fault
3. When a piece of equipment breaks down
Corrective maintenance can be subdivided into "immediate corrective maintenance" (in which
work starts immediately after a failure) and "deferred corrective maintenance" (in which work is
delayed in conformance to a given set of maintenance rules).
Corrective maintenance workflow
How corrective maintenance decreases downtime?

Think of corrective maintenance as something that gets caught just in time. For example, if you
see that the brake pads in your car are just about worn down but haven’t affected the rotors yet,
you caught them in time.
Within the maintenance arena, corrective maintenance is triggered when a technician sees
something that is about to break or will affect the overall performance of a piece of equipment. It
can still be repaired or restored without incurring downtime.
If corrective maintenance is not scheduled, the problem may become an emergency
maintenance work order down the road and result in halted production lines, interruption in
service, or unhappy customers.
Methods
The steps of corrective maintenance are, following failure, diagnosis – elimination of the part,
causing the failure – ordering the replacement – replacement of the part – test of function and
finally the continuation of use.
The basic form of corrective maintenance is a step-by-step procedure. The object's failure
triggers the steps. Modern technologies as the use of Industry 4.0 features reduce the inherant
drawbacks of corrective maintenance.[6] by e.g. providing device history, fault patterns, repair
advice or availability of spare parts.
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Types of corrective maintenance
Corrective maintenance is separated into planned and unplanned tasks.
Planned corrective maintenance
There are two ways that corrective maintenance can be planned.
1. Corrective maintenance is planned when a run-to-failure maintenance strategy is used.
This is when an asset is allowed to run until it breaks down and is then repaired or
replaced. This type of corrective maintenance only works with non-critical assets that are
easily and cheaply repaired or replaced, or with systems that have redundancies.
2. Corrective maintenance is planned when it’s performed as part of preventive
maintenance or condition-based monitoring. Both preventive and condition-based
maintenance attempt to find problems before they cause equipment failure. If a problem
is found, maintenance can be planned and scheduled.
Unplanned corrective maintenance
Corrective maintenance is considered unplanned in two situations.
1. Corrective maintenance is unplanned when a preventive maintenance schedule is in
place, but a breakdown occurs between scheduled maintenance actions. Maintenance can
be may be performed immediately or at a later date, depending on the availability of
tools, parts, and personnel.
2. Corrective maintenance can also be unplanned when an asset shows signs of potential
failure or reaches failure unexpectedly. In this scenario, there are no planned
maintenance actions to catch the failure before it happens or to address it after it happens.
Examples of corrective maintenance

There are several different scenarios where corrective maintenance can be used. These examples
can be split up into planned and unplanned tasks.
Examples of planned corrective maintenance
1. Imagine an asset has several fans. The asset can still operate properly if one breaks and
there are lots of extra fans in your storeroom, which means repairs are quick and
inexpensive. Because of this, you decide to let the fans run until one of them fails and
then replace it at that point. This is an example of run-to-fail corrective maintenance.
2. Let’s say you perform a preventive maintenance inspection on a conveyor system every
two weeks. During one of these inspections, you find that some bearings have been
damaged, so you replace them. This is an example of preventive corrective maintenance.
Examples of unplanned corrective maintenance
1. Pretend your facility has a compressor. You plan for it to be inspected and repaired after
every 100 hours of use in order to keep it functioning properly. However, the asset
breaks after only 75 hours of operation and you have to perform an emergency repair.
This is one example of unplanned corrective maintenance.
2. Unplanned corrective maintenance can also happen if you have no plan in place to
maintain, repair, or replace a piece of equipment before it fails. For example, your
facility can’t afford for one of its forklifts to break down, but there’s no preventive
maintenance done on the vehicles. When it breaks and a technician scrambles to get it
working again, this is considered unplanned corrective maintenance.
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When to use corrective maintenance?
Corrective maintenance can improve asset health and performance in situations when planned
maintenance occurs.
• When preventive maintenance tasks identify potential faults
• When condition-based monitoring finds machine anomalies that signal potential failure
• When non-critical assets can be allowed to run to failure and are inexpensive and easy to
repair or replace.
• When asset failure doesn’t affect safety
• When a system has redundancies that allow it to operate properly even if a part fails
Benefits of corrective maintenance

Since corrective maintenance is performed “just in time,” the main benefit is reduced emergency
maintenance orders as well as increased employee safety. Corrective maintenance work orders
are scheduled and prioritized in a CMMS, that helps maintenance teams resolve problems before
delays in production or service interruptions occur.
Corrective maintenance, coupled with good preventive maintenance, helps a business extend the
lifetime of its assets, reduce employee injury, and optimize resource planning. Corrective
maintenance work orders are often less expensive to implement than emergency maintenance
work orders may need to be completed during overtime hours.
Summary
In order to get the most benefit from corrective maintenance, organizations must provide training
to maintenance employees about what to look for when they are carrying out preventive
maintenance duties. Planning for corrective maintenance—by making sure that needed parts and
equipment are always available, for example—can also ensure that corrective maintenance
happens before disaster strikes. By maximizing planned corrective maintenance, organizations
can reduce unplanned corrective maintenance and the costly downtime that comes with it.
18
Reliability centred maintenance (RCM)
Reliability-Centered Maintenance (RCM) is the process of determining the most effective
maintenance approach. The RCM philosophy employs Preventive Maintenance (PM), Predictive
Maintenance (PdM), Real-time Monitoring (RTM1 ), Run-to-Failure (RTF- also called reactive
maintenance) and Proactive Maintenance techniques in an integrated manner to increase the
probability that a machine or component will function in the required manner over its design life
cycle with a minimum of maintenance. The goal of the philosophy is to provide the stated
function of the facility, with the required reliability and availability at the lowest cost. RCM
requires that maintenance decisions be based on maintenance requirements supported by sound
technical and economic justification.
Industry professionals have described an RCM program as:

• “The best way to develop a maintenance improvement program improvement program.”
– A. M. Smith
• A process that “uses a cross-functional team to develop a complete maintenance strategy
designed to ensure inherent design reliability for a process or piece of equipment.” –
Doug Plucknett
• A way “to identify components whose functional failures can cause unwanted
consequences to one’s plant or facility.” – Neil Bloom
A Brief History of RCM

Reliability Centered Maintenance originated in the Airline industry in the 1960’s. By the late
1950’s, the cost of Maintenance activities in this industry had become high enough to warrant a
special investigation into the effectiveness of those activities. Accordingly, in 1960, a task force
was formed consisting of representatives of both the airlines and the FAA to investigate the
capabilities of preventive maintenance. The establishment of this task force subsequently led to
the development of a series of guidelines for airlines and aircraft manufacturers to use, when
establishing maintenance schedules for their aircraft. This led to the 747 Maintenance Steering
Group (MSG) document MSG-1; Handbook: Maintenance Evaluation and Program
Development from the Air Transport Association in 1968. MSG-1 was used to develop the
maintenance program for the Boeing 747 aircraft, the first maintenance program to apply RCM
concepts. MSG-2, the next revision, was used to develop the maintenance programs for the
Lockheed L-1011 and the Douglas DC-10. The success of this program is demonstrated by
comparing maintenance requirements of a DC-8 aircraft, maintained using standard maintenance
techniques, and the DC-10 aircraft, maintained using MSG-2 guidelines. The DC-8 aircraft has
339 items that require an overhaul, verses only seven items on a DC-10. Using another example,
the original Boeing 747 required 66,000 labor hours on major structural inspections before a
major heavy inspection at 20,000 operating hours. In comparison, the DC-8 - a smaller and less
sophisticated aircraft using standard maintenance programs of the day required more than 4
million labor hours before reaching 20,000 operating hours. In 1974 the US Department of
Defense commissioned United Airlines to write a report on the processes used in the civil
aviation industry for the development of maintenance programs for aircraft. This report, written
by Stan Nowlan and Howard Heap and published in 1978, was entitled Reliability Centered 1 As
described later in this paper RTM and PdM are often combined under the heading of Condition
Based Maintenance, or CBM. Maintenance, and has become the report upon which all
subsequent Reliability Centered Maintenance approaches have been based. What Mr's Nowlan
19
and Heap found was many types of failures could not be prevented no matter how intensive the
maintenance activities. Additionally it was discovered that for many items the probability of
failure did not increase with age. Consequently, a maintenance program based on age will have
little, if any effect on the failure rate.
The primary RCM principles are:

1. RCM is Function Oriented – It seeks to preserve system or equipment function, not just
operability for operability's sake. Redundancy of function, through multiple equipment, improves
functional reliability, but increases life cycle cost in terms of procurement and operating costs.
2. RCM is System Focused – It is more concerned with maintaining system function than
individual component function.
3. RCM is Reliability Centered – It treats failure statistics in an actuarial manner. The
relationship between operating age and the failures experienced is important. RCM is not overly
concerned with simple failure rate; it seeks to know the conditional probability of failure at
specific ages (the probability that failure will occur in each given operating age bracket).
4. RCM Acknowledges Design Limitations – Its objective is to maintain the inherent reliability
of the equipment design, recognizing that changes in inherent reliability are the province of
design rather than maintenance. Maintenance can, at best, only achieve and maintain the level of
reliability for equipment, which is provided for by design. However, RCM recognizes that
maintenance feedback can improve on the original design. In addition, RCM recognizes that a
difference often exists between the perceived design life and the intrinsic or actual design life,
and addresses this through the Age Exploration (AE) process.
5. RCM is Driven by Safety and Economics – Safety must be ensured at any cost; thereafter,
cost-effectiveness becomes the criterion.
6. RCM Defines Failure as Any Unsatisfactory Condition – Therefore, failure may be either a
loss of function (operation ceases) or a loss of acceptable quality (operation continues).
7. RCM Uses a Logic Tree to Screen Maintenance Tasks – This provides a consistent approach
to the maintenance of all kinds of equipment. See Figure 1.
9. RCM Tasks Must Be Applicable – The tasks must address the failure mode and consider the
failure mode characteristics.
10. RCM Tasks Must Be Effective – The tasks must reduce the probability of failure and be cost
effective.
11. RCM Acknowledges Three Types of Maintenance Tasks a. Time-directed (PM) – Scheduled
when appropriate b. Condition-directed (PdM and real-time monitoring) – Performed when
conditions indicate they are needed c. Failure finding (one of several aspects of Proactive
Maintenance) – Equipment is run-tofailure. This is acceptable for some situations and some
types of equipment.
12. RCM is a Living System – It gathers data from the results achieved and feeds this data back
to improve design and future maintenance. This feedback is an important part of the Proactive
Maintenance element of the RCM program.
20
Reliability-Centered Maintenance is the As the airline industry showed 40 years significantly
reduce the required maintenance. monies saved, both from reduced failures will continue saving
money year after to remain on the sidelines doing things program into the 21st century.
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Maintenance schedule
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34
Total Productive Maintenance
Total Productive Maintenance (TPM) is a system of maintaining and improving the integrity of
production, safety and quality systems through the machines, equipment, processes, and employees
that add business value to an organization.
TPM focuses on keeping all equipment in top working condition to avoid breakdowns and delays in
manufacturing processes.
History
One of the first companies to gain from TPM was Nippondenso, a company that created parts for
Toyota. They became the first winner of the PM prize. An internationally accepted TPM benchmark
developed by the JIPM Seiichi Nakajima is therefore regarded as the father of TPM.
Objectives
The goal of TPM is the continuous improvement of equipment effectiveness through engaging those
that impact on it in small group improvement activities. Total quality management (TQM) and total
productive maintenance (TPM) are considered as the key operational activities of the quality
management system. In order for TPM to be effective, the full support of the total workforce is
required. This should result in accomplishing the goal of TPM: "Enhance the volume of the
production, employee morals, and job satisfaction."
The main objective of TPM is to increase the Overall Equipment Effectiveness (OEE) of plant
equipment. TPM addresses the causes for accelerated deterioration while creating the correct
environment between operators and equipment to create ownership.
OEE has three factors which are multiplied to give one measure called OEE
Performance x Availability x Quality = OEE
Each factor has two associated losses making 6 in total, these 6 losses are as follows:
Performance = (1) running at reduced speed – (2) Minor Stops
Availability = (3) Breakdowns – (4) Product changeover
Quality = (5) Startup rejects – (6) Running rejects
The objective finally is to identify then prioritize and eliminate the causes of the losses. This is done
by self-managing teams that solve problem. Employing consultants to create this culture is a
common practice.
So, if Availability is 95%, Performance is 97%, and Quality is 98%, then OEE is .95 x .97 x .98 =
90.3%
Implementation of TPM:
Following are the steps involved by the implementation of TPM in an organization:[2]
1. Initial evaluation of TPM level,
2. Introductory Education and Propaganda (IEP) for TPM,
3. Formation of TPM committee,
4. Development of a master plan for TPM implementation,
5. Stage by stage training to the employees and stakeholders on all eight pillars of TPM,
6. Implementation preparation process,
7. Establishing the TPM policies and goals and development of a road map for TPM
implementation.
The steering committee may consist of production managers, maintenance managers, and
engineering managers. The committee should formulate TPM policies and strategies and give
advice. This committee should be led by a top-level executive. Also a TPM program team must rise,
this program team has oversight and coordination of implementation activities. As well, it's lacking
some crucial activities, like starting with partial implementation. Choose the first target area as a pilot
35
area, this area will demonstrate the TPM concepts. Lessons learned from early target areas/the pilot
area can be applied further in the implementation process.
The eight pillars of TPM are mostly focused on proactive and preventive techniques for improving equipment
reliability:
1. Autonomous Maintenance
2. 5S
3. Planned Maintenance
4. Quality management
5. Kaizen
6. Education and Training
7. Administrative & office TPM
8. Safety Health Environmental conditions
With the help of these pillars, we can increase productivity. Manufacturing support.
36
2/11/2020 An Introduction to Total Productive Maintenance (TPM)
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An Introduction to Total Productive Maintenance (TPM)

By Venkatesh J
What is Total Productive Maintenance ( TPM ) ?

It can be considered as the medical science of machines. 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 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.
Why TPM ?
TPM was introduced to achieve the following objectives. The important ones are listed below.
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.
Similarities and differences between TQM and TPM :

The TPM program closely resembles the popular Total Quality Management (TQM) program. Many of the tools such as
employee empowerment, benchmarking, documentation, etc. used in TQM are used to implement and optimize
TPM.Following are the similarities between the two.
1. Total commitment to the program by upper level management is required in both programmes
2. Employees must be empowered to initiate corrective action, and
3. A long range outlook must be accepted as TPM may take a year or more to implement and is an on-going process. Changes in
employee mind-set toward their job responsibilities must take place as well.
The differences between TQM and TPM is summarized below.
Category TQM TPM
Object Quality ( Output and effects ) Equipment ( Input and cause )
Systematize the management. It is Employees participation and it is

Mains of attaining goal
software oriented hardware oriented
Target Quality for PPM Elimination of losses and wastes.
Types of maintenance :
1. Breakdown maintenance :
It means that people waits until equipment fails and repair it. Such a thing could be used when the equipment failure does not
significantly affect the operation or production or generate any significant loss other than repair cost.
2. Preventive maintenance ( 1951 ):

It is a daily maintenance ( cleaning, inspection, oiling and re-tightening ), design to retain the healthy condition of equipment
and prevent failure through the prevention of deterioration, periodic inspection or equipment condition diagnosis, to measure
deterioration. It is further divided into periodic maintenance and predictive maintenance. Just like human life is extended by
preventive medicine, the equipment service life can be prolonged by doing preventive maintenance.
2a. Periodic maintenance ( Time based maintenance - TBM) :

Time based maintenance consists of periodically inspecting, servicing and cleaning equipment and replacing
parts to prevent sudden failure and process problems.
www.plant-maintenance.com/articles/tpm_intro.shtml 1/10
2b. Predictive maintenance :
This is a method in which the service life of important part is predicted based on inspection or diagnosis, in
order to use the parts to the limit of their service life. Compared to periodic maintenance, predictive
maintenance is condition based maintenance. It manages trend values, by measuring and analyzing data about
deterioration and employs a surveillance system, designed to monitor conditions through an on-line system.
3. Corrective maintenance ( 1957 ) :

It improves equipment and its components so that preventive maintenance can be carried out reliably. Equipment with design
weakness must be redesigned to improve reliability or improving maintainability
4. Maintenance prevention ( 1960 ):

It indicates the design of a new equipment. Weakness of current machines are sufficiently studied ( on site information
leading to failure prevention, easier maintenance and prevents of defects, safety and ease of manufacturing ) and are
incorporated before commissioning a new equipment.
TPM - History:
TPM is a innovative Japanese concept. The origin of TPM can be traced back to 1951 when preventive maintenance was
introduced in Japan. However the concept of preventive maintenance was taken from USA. Nippondenso was the first
company to introduce plant wide preventive maintenance in 1960. Preventive maintenance is the concept wherein, operators
produced goods using machines and the maintenance group was dedicated with work of maintaining those machines,
however with the automation of Nippondenso, maintenance became a problem as more maintenance personnel were
required. So the management decided that the routine maintenance of equipment would be carried out by the operators. (
This is Autonomous maintenance, one of the features of TPM ). Maintenance group took up only essential maintenance
works.
Thus Nippondenso which already followed preventive maintenance also added Autonomous maintenance done by
production operators. The maintenance crew went in the equipment modification for improving reliability. The modifications
were made or incorporated in new equipment. This lead to maintenance prevention. Thus preventive maintenance along with
Maintenance prevention and Maintainability Improvement gave birth to Productive maintenance. The aim of productive
maintenance was to maximize plant and equipment effectiveness to achieve optimum life cycle cost of production equipment.
By then Nippon Denso had made quality circles, involving the employees participation. Thus all employees took part in
implementing Productive maintenance. Based on these developments Nippondenso was awarded the distinguished plant
prize for developing and implementing TPM, by the Japanese Institute of Plant Engineers ( JIPE ). Thus Nippondenso of the
Toyota group became the first company to obtain the TPM certification.
TPM Targets:
P
Obtain Minimum 80% OPE.
Obtain Minimum 90% OEE ( Overall Equipment Effectiveness )
Run the machines even during lunch. ( Lunch is for operators and not for machines ! )
Q
Operate in a manner, so that there are no customer complaints.
C
Reduce the manufacturing cost by 30%.
D
Achieve 100% success in delivering the goods as required by the customer.
S
Maintain a accident free environment.
M
Increase the suggestions by 3 times. Develop Multi-skilled and flexible workers.
Motives of TPM 1. Adoption of life cycle approach for improving the overall performance of
production equipment.
2. Improving productivity by highly motivated workers which is achieved by job
enlargement.
3. The use of voluntary small group activities for identifying the cause of failure,
possible plant and equipment modifications.
Uniqueness of TPM The major difference between TPM and other concepts is that the operators
are also made to involve in the maintenance process. The concept of "I (
Production operators ) Operate, You ( Maintenance department ) fix" is not
followed.
TPM Objectives 1. Achieve Zero Defects, Zero Breakdown and Zero accidents in all functional
areas of the organization.
2. Involve people in all levels of organization.
3. Form different teams to reduce defects and Self Maintenance.
Direct benefits of TPM 1. Increase productivity and OPE ( Overall Plant Efficiency ) by 1.5 or 2 times.
2. Rectify customer complaints.
3. Reducethe manufacturing cost by 30%.
4. Satisfy the customers needs by 100 % ( Delivering the right quantity at the right
time, in the required quality. )
5. Reduce accidents.
6. Follow pollution control measures.
Indirect benefits of TPM 1. Higher confidence level among the employees.

2. Keep the work place clean, neat and attractive.
3. Favorablechange in the attitude of the operators.
4. Achieve goals by working as team.
5. Horizontaldeployment of a new concept in all areas of the organization.
6. Share knowledge and experience.
7. The workers get a feeling of owning the machine.
OEE ( Overall Equipment Efficiency ) :

OEE = A x PE x Q
A - Availability of the machine. Availability is proportion of time machine is actually available out of time it should be available.
A = ( MTBF - MTTR ) / MTBF.
MTBF - Mean Time Between Failures = ( Total Running Time ) / Number of Failures.
MTTR - Mean Time To Repair.
PE - Performance Efficiency. It is given by RE X SE.
Rate efficiency (RE) : Actual average cycle time is slower than design cycle time because of jams, etc. Output is reduced
because of jams
Speed efficiency (SE) : Actual cycle time is slower than design cycle time machine output is reduced because it is running at
reduced speed.
Q - Refers to quality rate. Which is percentage of good parts out of total produced sometimes called "yield".
Steps in introduction of TPM in a organization :

Step A - PREPARATORY STAGE :
STEP 1 - Announcement by Management to all about TPM introduction in the organization :
Proper understanding, commitment and active involvement of the top management in needed for this step. Senior
management should have awareness programmes, after which announcement is made to all. Publish it in the house
magazine and put it in the notice board. Send a letter to all concerned individuals if required.
STEP 2 - Initial education and propaganda for TPM :
Training is to be done based on the need. Some need intensive training and some just an awareness. Take people who
matters to places where TPM already successfully implemented.
STEP 3 - Setting up TPM and departmental committees :
TPM includes improvement, autonomous maintenance, quality maintenance etc., as part of it. When committees are set up it
should take care of all those needs.
STEP 4 - Establishing the TPM working system and target :
Now each area is benchmarked and fix up a target for achievement.
STEP 5 - A master plan for institutionalizing :
Next step is implementation leading to institutionalizing wherein TPM becomes an organizational culture. Achieving PM
award is the proof of reaching a satisfactory level.
STEP B - INTRODUCTION STAGE

This is a ceremony and we should invite all. Suppliers as they should know that we want quality supply from them. Related
companies and affiliated companies who can be our customers, sisters concerns etc. Some may learn from us and some can
help us and customers will get the communication from us that we care for quality output.
STAGE C - IMPLEMENTATION
In this stage eight activities are carried which are called eight pillars in the development of TPM activity.
Of these four activities are for establishing the system for production efficiency, one for initial control system of new products
and equipment, one for improving the efficiency of administration and are for control of safety, sanitation as working
environment.
STAGE D - INSTITUTIONALISING STAGE

By all there activities one would has reached maturity stage. Now is the time for applying for PM award. Also think of
challenging level to which you can take this movement.
Organization Structure for TPM Implementation :
Pillars of TPM
PILLAR 1 - 5S :
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.
Japanese Term English Translation Equivalent 'S' term
Seiri Organisation Sort
Seiton Tidiness Systematise
Seiso Cleaning Sweep
Seiketsu Standardisation Standardise
Shitsuke Discipline Self - Discipline
SEIRI - Sort out :
This means sorting and organizing the items as critical, important, frequently used items, useless, or items that are not need
as of now. Unwanted items can be salvaged. Critical items should be kept for use nearby and items that are not be used in
near future, should be stored in some place. For this step, the worth of the item should be decided based on utility and not
cost. As a result of this step, the search time is reduced.
Priority Frequency of Use How to use
Throw away, Store away from the

Low Less than once per year, Once per year<
workplace
Average At least 2/6 months, Once per month, Store together but offline
Once per week
High Once Per Day Locate at the workplace
SEITON - Organise :
The concept here is that "Each items has a place, and only one place". The items should be placed back after usage at the
same place. To identify items easily, name plates and colored tags has to be used. Vertical racks can be used for this
purpose, and heavy items occupy the bottom position in the racks.
SEISO - Shine the workplace :
This involves cleaning the work place free of burrs, grease, oil, waste, scrap etc. No loosely hanging wires or oil leakage from
machines.
SEIKETSU - Standardization :
Employees has to discuss together and decide on standards for keeping the work place / Machines / pathways neat and
clean. This standards are implemented for whole organization and are tested / Inspected randomly.
SHITSUKE - Self discipline :
Considering 5S as a way of life and bring about self-discipline among the employees of the organization. This includes
wearing badges, following work procedures, punctuality, dedication to the organization etc.
PILLAR 2 - JISHU HOZEN ( Autonomous maintenance ) :

This pillar is geared towards developing operators to be able to take care of small maintenance tasks, thus freeing up the
skilled maintenance people to spend time on more value added activity and technical repairs. The operators are responsible
for upkeep of their equipment to prevent it from deteriorating.
Policy :
1. Uninterrupted operation of equipments.

2. Flexible operators to operate and maintain other equipments.
3. Eliminating the defects at source through active employee participation.
4. Stepwise implementation of JH activities.
JISHU HOZEN Targets:
1. Prevent the occurrence of 1A / 1B because of JH.

2. Reduce oil consumption by 50%
3. Reduce process time by 50%
4. Increase use of JH by 50%
Steps in JISHU HOZEN :
1. Preparation of employees.
2. Initial cleanup of machines.
3. Take counter measures
4. Fix tentative JH standards
5. General inspection
6. Autonomous inspection
7. Standardization and
8. Autonomous management.
Each of the above mentioned steps is discussed in detail below.
1. Train the Employees : Educate the employees about TPM, Its advantages, JH advantages and Steps in JH. Educate the
employees about abnormalities in equipments.
2. Initial cleanup of machines :
Supervisor and technician should discuss and set a date for implementing step1
Arrange all items needed for cleaning
On the arranged date, employees should clean the equipment completely with the help of maintenance department.
Dust, stains, oils and grease has to be removed.
Following are the things that has to be taken care while cleaning. They are Oil leakage, loose wires, unfastened nits and
bolts and worn out parts.
After clean up problems are categorized and suitably tagged. White tags is place where problems can be solved by
operators. Pink tag is placed where the aid of maintenance department is needed.
Contents of tag is transferred to a register.
Make note of area which were inaccessible.
Finally close the open parts of the machine and run the machine.
3. Counter Measures :
Inaccessible regions had to be reached easily. E.g. If there are many screw to open a fly wheel door, hinge door can be
used. Instead of opening a door for inspecting the machine, acrylic sheets can be used.
To prevent work out of machine parts necessary action must be taken.
Machine parts should be modified to prevent accumulation of dirt and dust.
4. Tentative Standard :
JH schedule has to be made and followed strictly.
Schedule should be made regarding cleaning, inspection and lubrication and it also should include details like when, what
and how.
5. General Inspection :
The employees are trained in disciplines like Pneumatics, electrical, hydraulics, lubricant and coolant, drives, bolts, nuts and
Safety.
This is necessary to improve the technical skills of employees and to use inspection manuals correctly.
After acquiring this new knowledge the employees should share this with others.
By acquiring this new technical knowledge, the operators are now well aware of machine parts.
6. Autonomous Inspection :
New methods of cleaning and lubricating are used.
Each employee prepares his own autonomous chart / schedule in consultation with supervisor.
Parts which have never given any problem or part which don't need any inspection are removed from list permanently
based on experience.
Including good quality machine parts. This avoid defects due to poor JH.
Inspection that is made in preventive maintenance is included in JH.
The frequency of cleanup and inspection is reduced based on experience.
7. Standardization :
Upto the previous stem only the machinery / equipment was the concentration. However in this step the surroundings of
machinery are organized. Necessary items should be organized, such that there is no searching and searching time is
reduced.
Work environment is modified such that there is no difficulty in getting any item.
Everybody should follow the work instructions strictly.
Necessary spares for equipments is planned and procured.
8. Autonomous Management :
OEE and OPE and other TPM targets must be achieved by continuous improve through Kaizen.
PDCA ( Plan, Do, Check and Act ) cycle must be implemented for Kaizen.
PILLAR 3 - KAIZEN :
"Kai" means change, and "Zen" means good ( for the better ). Basically kaizen is for small improvements, but carried out on a
continual basis and involve all people in the organization. Kaizen is opposite to big spectacular innovations. Kaizen requires
no or little investment. The principle behind is that "a very large number of small improvements are move effective in an
organizational environment than a few improvements of large value. This pillar is aimed at reducing losses in the workplace
that affect our efficiencies. By using a detailed and thorough procedure we eliminate losses in a systematic method using
various Kaizen tools. These activities are not limited to production areas and can be implemented in administrative areas as
well.
Kaizen Policy :
1. Practice concepts of zero losses in every sphere of activity.

2. relentless pursuit to achieve cost reduction targets in all resources
3. Relentless pursuit to improve over all plant equipment effectiveness.
4. Extensive use of PM analysis as a tool for eliminating losses.
5. Focus of easy handling of operators.
Kaizen Target :
Achieve and sustain zero loses with respect to minor stops, measurement and adjustments, defects and unavoidable
downtimes. It also aims to achieve 30% manufacturing cost reduction.
Tools used in Kaizen :
1. PM analysis
2. Why - Why analysis
3. Summary of losses
4. Kaizen register
5. Kaizen summary sheet.
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 16 major losses.
16 Major losses in a organisation:
Loss Category
1. Failure losses - Breakdown loss Losses that impede equipment efficiency

2. Setup / adjustment losses
3. Cutting blade loss
4. Start up loss
5. Minor stoppage / Idling loss.
6. Speed loss - operating at low speeds.
7. Defect / rework loss
8. Scheduled downtime loss
9. Management loss
10. Operating motion loss
11. Line organization loss
Loses that impede human work efficiency
12. Logistic loss
13. Measurement and adjustment loss
14. Energy loss

15. Die, jig and tool breakage loss
Loses that impede effective use of production resources
16. Yield loss.
Classification of losses :
Aspect Sporadic Loss Chronic Loss

Causes for this failure can be easily This loss cannot be easily identified and
Causation traced. Cause-effect relationship is solved. Even if various counter measures
simple to trace. are applied
This type of losses are caused because
Remedy Easy to establish a remedial measure of hidden defects in machine, equipment
and methods.
A single cause is rare - a combination of

Impact / Loss A single loss can be costly
causes trends to be a rule
The frequency of occurrence is low and

Frequency of occurrence The frequency of loss is more.
occasional.
Specialists in process engineering,

Usually the line personnel in the
Corrective action quality assurance and maintenance
production can attend to this problem.
people are required.
PILLAR 4 - PLANNED MAINTENANCE :

It is aimed to have trouble free machines and equipments producing defect free products for total customer satisfaction. This
breaks maintenance down into 4 "families" or groups which was defined earlier.
1. Preventive Maintenance
2. Breakdown Maintenance
3. Corrective Maintenance
4. Maintenance Prevention
With Planned Maintenance we evolve our efforts from a reactive to a proactive method and use trained maintenance staff to
help train the operators to better maintain their equipment.
Policy :
1. Achieve and sustain availability of machines

2. Optimum maintenance cost.
3. Reduces spares inventory.
4. Improve reliability and maintainability of machines.
Target :
1. Zero equipment failure and break down.

2. Improve reliability and maintainability by 50 %
3. Reduce maintenance cost by 20 %
4. Ensure availability of spares all the time.
Six steps in Planned maintenance :
1. Equipment evaluation and recoding present status.

2. Restore deterioration and improve weakness.
3. Building up information management system.
4. Prepare time based information system, select equipment, parts and members and map out plan.
5. Prepare predictive maintenance system by introducing equipment diagnostic techniques and
6. Evaluation of planned maintenance.
PILLAR 5 - QUALITY MAINTENANCE :

It is aimed towards customer delight through highest quality through defect free manufacturing. Focus is on eliminating non-
conformances in a systematic manner, much like Focused Improvement. We gain understanding of what parts of the
equipment affect product quality and begin to eliminate current quality concerns, then move to potential quality concerns.
Transition is from reactive to proactive (Quality Control to Quality Assurance).
QM activities is to set equipment conditions that preclude quality defects, based on the basic concept of maintaining perfect
equipment to maintain perfect quality of products. The condition are checked and measure in time series to very that
measure values are within standard values to prevent defects. The transition of measured values is watched to predict
possibilities of defects occurring and to take counter measures before hand.
Policy :
1. Defect free conditions and control of equipments.

2. QM activities to support quality assurance.
3. Focus of prevention of defects at source
4. Focus on poka-yoke. ( fool proof system )
5. In-line detection and segregation of defects.
6. Effective implementation of operator quality assurance.
Target :
1. Achieve and sustain customer complaints at zero

2. Reduce in-process defects by 50 %
3. Reduce cost of quality by 50 %.
Data requirements :
Quality defects are classified as customer end defects and in house defects. For customer-end data, we have to get data on
1. Customer end line rejection

2. Field complaints.
In-house, data include data related to products and data related to process
Data related to product :
1. Product wise defects

2. Severity of the defect and its contribution - major/minor
3. Location of the defect with reference to the layout
4. Magnitude and frequency of its occurrence at each stage of measurement
5. Occurrence trend in beginning and the end of each production/process/changes. (Like pattern change, ladle/furnace lining etc.)
6. Occurrence trend with respect to restoration of breakdown/modifications/periodical replacement of quality components.
Data related to processes:
1. The operating condition for individual sub-process related to men, method, material and machine.
2. The standard settings/conditions of the sub-process
3. The actual record of the settings/conditions during the defect occurrence.
PILLAR 6 - TRAINING :
It is aimed to have multi-skilled revitalized employees whose morale is high and who has eager to come to work and perform
all required functions effectively and independently. Education is given to operators to upgrade their skill. It is not sufficient
know only "Know-How" by they should also learn "Know-why". By experience they gain, "Know-How" to overcome a problem
what to be done. This they do without knowing the root cause of the problem and why they are doing so. Hence it become
necessary to train them on knowing "Know-why". The employees should be trained to achieve the four phases of skill. The
goal is to create a factory full of experts. The different phase of skills are
Phase 1 : Do not know.

Phase 2 : Know the theory but cannot do.
Phase 3 : Can do but cannot teach
Phase 4 : Can do and also teach.
Policy :
1. Focus on improvement of knowledge, skills and techniques.

2. Creating a training environment for self learning based on felt needs.
3. Training curriculum / tools /assessment etc conductive to employee revitalization
4. Training to remove employee fatigue and make work enjoyable.
Target :
1. Achieve and sustain downtime due to want men at zero on critical machines.
2. Achieve and sustain zero losses due to lack of knowledge / skills / techniques
3. Aim for 100 % participation in suggestion scheme.
Steps in Educating and training activities :
1. Setting policies and priorities and checking present status of education and training.
2. Establish of training system for operation and maintenance skill up gradation.
3. Training the employees for upgrading the operation and maintenance skills.
4. Preparation of training calendar.
5. Kick-off of the system for training.
6. Evaluation of activities and study of future approach.
PILLAR 7 - OFFICE TPM :
Office TPM should be started after activating four other pillars of TPM (JH, KK, QM, PM). Office TPM must be followed to
improve productivity, efficiency in the administrative functions and identify and eliminate losses. This includes analyzing
processes and procedures towards increased office automation. Office TPM addresses twelve major losses. They are
1. Processing loss
2. Cost loss including in areas such as procurement, accounts, marketing, sales leading to high inventories
3. Communication loss
4. Idle loss
5. Set-up loss
6. Accuracy loss
7. Office equipment breakdown
8. Communication channel breakdown, telephone and fax lines
9. Time spent on retrieval of information
10. Non availability of correct on line stock status
11. Customer complaints due to logistics
12. Expenses on emergency dispatches/purchases
How to start office TPM ?
A senior person from one of the support functions e.g. Head of Finance, MIS, Purchase etc should be heading the sub-
committee. Members representing all support functions and people from Production & Quality should be included in sub
committee. TPM co-ordinate plans and guides the sub committee.
1. Providing awareness about office TPM to all support departments

2. Helping them to identify P, Q, C, D, S, M in each function in relation to plant performance
3. Identify the scope for improvement in each function
4. Collect relevant data
5. Help them to solve problems in their circles
6. Make up an activity board where progress is monitored on both sides - results and actions along with Kaizens.
7. Fan out to cover all employees and circles in all functions.
Kobetsu Kaizen topics for Office TPM :
Inventory reduction
Lead time reduction of critical processes
Motion & space losses
Retrieval time reduction.
Equalizing the work load
Improving the office efficiency by eliminating the time loss on retrieval of information, by achieving zero breakdown of office
equipment like telephone and fax lines.
Office TPM and its Benefits :
1. Involvement of all people in support functions for focusing on better plant performance
2. Better utilized work area
3. Reduce repetitive work
4. Reduced inventory levels in all parts of the supply chain
5. Reduced administrative costs
6. Reduced inventory carrying cost
7. Reduction in number of files
8. Reduction of overhead costs (to include cost of non-production/non capital equipment)
9. Productivity of people in support functions
10. Reduction in breakdown of office equipment
11. Reduction of customer complaints due to logistics
12. Reduction in expenses due to emergency dispatches/purchases
13. Reduced manpower
14. Clean and pleasant work environment.
P Q C D S M in Office TPM :
P - Production output lost due to want of material, Manpower productivity, Production output lost due to want of tools.
Q - Mistakes in preparation of cheques, bills, invoices, payroll, Customer returns/warranty attributable to BOPs,
Rejection/rework in BOP's/job work, Office area rework.
C - Buying cost/unit produced, Cost of logistics - inbound/outbound, Cost of carrying inventory, Cost of communication,
Demurrage costs.
D - Logistics losses (Delay in loading/unloading)
Delay in delivery due to any of the support functions

Delay in payments to suppliers
Delay in information
S - Safety in material handling/stores/logistics, Safety of soft and hard data.
M - Number of kaizens in office areas.

How office TPM supports plant TPM :
Office TPM supports the plant, initially in doing Jishu Hozen of the machines (after getting training of Jishu Hozen), as in
Jishu Hozen at the
1. Initial stages machines are more and manpower is less, so the help of commercial departments can be taken, for this
2. Office TPM can eliminate the lodes on line for no material and logistics.
Extension of office TPM to suppliers and distributors :
This is essential, but only after we have done as much as possible internally. With suppliers it will lead to on-time delivery,
improved 'in-coming' quality and cost reduction. With distributors it will lead to accurate demand generation, improved
secondary distribution and reduction in damages during storage and handling. In any case we will have to teach them based
on our experience and practice and highlight gaps in the system which affect both sides. In case of some of the larger
companies, they have started to support clusters of suppliers.
PILLAR 8 - SAFETY, HEALTH AND ENVIRONMENT :
Target :
1. Zero accident,
2. Zero health damage
3. Zero fires.
In this area focus is on to create a safe workplace and a surrounding area that is not damaged by our process or procedures.
This pillar will play an active role in each of the other pillars on a regular basis.
A committee is constituted for this pillar which comprises representative of officers as well as workers. The committee is
headed by Senior vice President ( Technical ). Utmost importance to Safety is given in the plant. Manager (Safety) is looking
after functions related to safety. To create awareness among employees various competitions like safety slogans, Quiz,
Drama, Posters, etc. related to safety can be organized at regular intervals.
Conclusion:
Today, with competition in industry at an all time high, TPM may be the only thing that stands between success and total
failure for some companies. It has been proven to be a program that works. It can be adapted to work not only in industrial
plants, but in construction, building maintenance, transportation, and in a variety of other situations. Employees must be
educated and convinced that TPM is not just another "program of the month" and that management is totally committed to
the program and the extended time frame necessary for full implementation. If everyone involved in a TPM program does his
or her part, an unusually high rate of return compared to resources invested may be expected.
Copyright 1996-2006, The Plant Maintenance Resource Center . All Rights Reserved.
Revised: Thursday, 08-Oct-2015 11:54:54 AEDT
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Unit 2 - Maintenance Categories

Types of preventive maintenance

Preventive Maintenance Workflow

How preventive maintenance decreases downtime?

Benefits of preventive maintenance

Advantages of preventive maintenance

Advantages compared with less complex strategies

Advantages compared with more complex strategies

Disadvantages compared with less complex strategies

Predictive maintenance (PdM) is a type of condition-based maintenance that monitors the

How predictive maintenance compares to other options

A brief history of predictive maintenance

How does predictive maintenance work?

Predictive maintenance workflow

Note: Predictive maintenance workflow exmaple

Note: Using vibration analysis in predictive maintenance on a motor

Acoustical analysis (sonic)

According to an article by Machinery Lubrication, “Acoustic analysis is similar to vibration

Model Based Condition Monitoring

Example of predictive maintenance

The benefits of predictive maintenance

The ROI of predictive maintenance

Applications (by industry)

Condition-based maintenance (CBM) is a maintenance strategy that monitors the actual

What’s the goal of condition-based maintenance?

Example of condition-based maintenance

Condition monitoring technology

Types of condition based maintenance

• Infrared: IR cameras can be used to detect high-temperature conditions in energized

• Often visual inspections are considered to form an underlying component of condition

• Performance analysis, where the physical efficiency, performance, or condition is found by

Challenges of condition-based maintenance

Corrective maintenance workflow

How corrective maintenance decreases downtime?

Examples of corrective maintenance

Benefits of corrective maintenance

Industry professionals have described an RCM program as:

A Brief History of RCM

The primary RCM principles are:

Plant Maintenance Resource Center

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An Introduction to Total Productive Maintenance (TPM)

What is Total Productive Maintenance ( TPM ) ?

Avoid wastage in a quickly changing economic environment.

Similarities and differences between TQM and TPM :

The differences between TQM and TPM is summarized below.

Category TQM TPM

Object Quality ( Output and effects ) Equipment ( Input and cause )

Systematize the management. It is Employees participation and it is

Target Quality for PPM Elimination of losses and wastes.

2. Preventive maintenance ( 1951 ):

2a. Periodic maintenance ( Time based maintenance - TBM) :

3. Corrective maintenance ( 1957 ) :

4. Maintenance prevention ( 1960 ):

Indirect benefits of TPM 1. Higher confidence level among the employees.

OEE ( Overall Equipment Efficiency ) :

A = ( MTBF - MTTR ) / MTBF.

PE - Performance Efficiency. It is given by RE X SE.

Steps in introduction of TPM in a organization :

STEP 1 - Announcement by Management to all about TPM introduction in the organization :