Thursday, August 12, 2010

How to get the most out of your CMMS

Experience shows there are three key groups that must buy in on the initial selection of a computerized maintenance management system (CMMS) and then the ongoing use of the system. Common to each of these groups is an understanding of their culture and the environment in which the system will be used. This is critical to CMMS success.

1) Maintenance: Technicians must see the CMMS as a tool that will help them do a better job, be more efficient and improve work processes. It can't be viewed as a system management is using to "watch them" or give the perception that someone always is peering over their shoulder.

Because technicians will use the CMMS daily, they will grow to depend on it. Early acceptance is important and buy-in during the initial evaluations is critical. Their CMMS will become an integral tool that they learn to rely on and trust in for helping them do their jobs to their best abilities as maintenance professionals every day.

2) Equipment users: Production and engineering personnel must see the value CMMS delivers for prompt and effective maintenance. These are the resources responsible for producing product and generating output; therefore, their lines must operate at their highest levels as much as possible. Preventive maintenance must be coordinated with production and unplanned maintenance must be performed quickly so as not to impact production.

Personnel at the equipment level will be able to recognize the value of a CMMS and understand that proactive maintenance on critical equipment is essential. Having the right CMMS tool that enables maintenance pros to do this work is key.

3) Management: People in management roles should view the CMMS as a means of obtaining metrics regarding maintenance deployment and equipment performance. Through reporting on work performed, planned and in process, management can improve its decision-making process. Having updated information on equipment maintenance history and relative maintenance cost enables management to control resources and costs more effectively. The right CMMS must be able to provide the data management needs for this process.

Bringing these groups together during the selection and implementation planning stages will set the tone for ongoing CMMS success. Such a process will also encourage user input to help determine the type of system that is the best fit for the company. This should take into account the size of organization that will be using the CMMS, functionality required, facility type, budget and return on investment. These components will influence how an organization will achieve the desired results from a CMMS.
IMPLEMENTATION
Software will not "implement itself." Unfortunately, many companies aren't deriving much benefit from their CMMS because the system has been poorly implemented. By taking a systematic approach to the CMMS implementation, organizations will be on a better path for success.

Database building must be planned and checked for effectiveness at predetermined steps. It is essential to have one person actively involved and in charge to ensure proper implementation. Many implementations fail because the database hasn't been built systematically; several people have entered their own data without direction as to what is needed or expected, resulting in a system that only can be used by the implementer. Proper implementation consists of building the database to match the environment (data formats, how data is recorded, manipulated and managed) and developing a systematic use of the CMMS that is consistent on a daily basis.

Training on how to use the CMMS is often a key component of implementation and provides a disciplined approach to best system usage. It also provides a means for educating multiple users across different disciplines on how to use the system for each of their areas.

CONCLUSION
Software alone won't improve how an organization handles maintenance. System users must understand how the CMMS works and how it can be trusted as a tool to improve work processes and effectiveness. Maintenance, equipment users and management all should view a CMMS as a means for controlling costs and increasing capacity. Having this mind-set is a huge step toward getting the most from a system.

Source: www.benchmate.com.

Tuesday, August 10, 2010

Predictive Maintenance (PdM) and Preventive Maintenance (PM)

One of the employee ask me, What is the difference between Preventive Maintenance (PM) and Predictive Maintenance (PdM)?

Here's an straight answer:

"The distinction between preventive maintenance (PM) and predictive maintenance (PdM) is that PdM tracks performance based on conditions while PM is a time-based replacement or service process"
The question now is... what is the best between these two?

Static and dynamic testing as part of PdM programs

by Timothy Thomas, Baker Instrument Company


Predictive maintenance programs (PMPs) are becoming universally accepted as the best method for maintaining motor reliability within most modern plants and facilities. A complete PMP will include as many technologies as possible, with each technology providing vital pieces to the diagnostic puzzle. Periodic static testing and more aggressive dynamic testing of motors are essential parts of predicting the potential for a motor to continue a safe and successful operation. Tracking and trending the results of electric motor testing on a regular schedule is the most effective method of making intelligent predictions.

The need for motor testing

The steady, safe and efficient operation of electric motors is essential to the productivity of all plants and facilities. Some facilities have many critical and/or expensive motors. A motor failure could be catastrophic, causing lost production and costly emergency repairs. For example, a motor failure at a nuclear plant can cost up to $1 million a day for critical motors and may have a disastrous, long-lasting impact. Even failures at a wastewater treatment facility can have a huge, negative environmental effect and can be very costly.

Motors fail due to numerous operational circumstances, including power condition, mechanical influences and environmental hazards. According to IEEE1 and EPRI2 studies, at least 35 to 45 percent of motor failures are electrically related. Monitoring the motors “electrical health” is, unquestionably, an important and vital consideration.

Trending the historical operating condition of a motor makes early detection of any decline in the motors “health” possible. Planning downtime and having only minor reconditioning repairs instead of a major rewind or replacement is far less expensive in both repair costs and lost production. Since electric motors begin deteriorating the instant they are started, it is necessary to monitor their operating condition on a routine, periodic schedule. Periodic monitoring and trending of data collected and properly diagnosed provides the technician with evidence needed to prepare for downtime before a catastrophe occurs.

It is no longer practical to just “megger” a motor in order to determine its condition. Plants and facilities depend on a complete predictive maintenance program (PMP) to monitor their operations and plan their repair schedules. A good PMP requires both static (and off-line) and dynamic (or on-line) testing, with educated and trained technicians monitoring data routinely, with quality equipment.

Besides voltages and currents, on-line test equipment must be able to capture and trend torque ripple and torque signatures as well as rotor bar sidebands. Off-line testing with modern, high-voltage test equipment is essential to getting reliable data. The voltages required to properly test motor windings cannot be reached with impedance-based or low-voltage test equipment.

On-line testing

Effective dynamic test equipment must be able to collect and trend all essential data that affects the operation of electric motors. Power condition – including voltage level, voltage imbalance and harmonic distortions, current levels and current imbalances, load levels, torque signatures, rotor bar signatures, service factors and efficiencies – should be tracked and trended.

On-line testing is performed at the motor’s MCC, at the load side of a variable frequency drive or at an installed port, which allows for on-line testing without opening the MCC. Data is collected through a set of current transformers and corresponding voltage probes. The data collected, processed and analyzed provides the technician with an overall view of the normal operational environment to which the motor is subjected on a daily basis and of how the motor is responding within this environment.

Often, a motor is subjected to incoming power problems including low or high voltages, voltage imbalances and harmonic distortions. Lower voltages cause higher currents and, therefore, more heat. Higher voltages cause lower power factors and ultimately higher losses. A small amount of voltage imbalance creates an exponential amount of current imbalance which causes temperature increases. Harmonic distortion also causes thermal stress in motors. Any of these voltage problems can cause severe overheating in the motor even without factually reaching an over-load situation, and excessive heat is the insulation’s major enemy. Some motors are subjected to physical obstacles that cause undue stress. Over-greasing, misalignment and over-tightened belts all cause thermal stress.

Many motor failures can be traced to load related situations. Erratic torque signatures can be an indicator of load-related problems. Broken or cracked rotor bars also can cause premature motor failures. On-line testing identifies these problems, and routine trending will reveal the rate of decline. Of major importance to the overall health of a motor also is the “effective service factor.” Two elements affect the service factor number are: real operating power condition (voltage quality) and steady state load conditions. The effective service factor number represents the thermal stress caused by these two conditions on the motor. On-line testing can find and trend all of these motor conditions.

Dynamic testing schedules should be tailored individually according to operating time, criticality and any other important element of operation. Generally, an on-line test should be performed at least quarterly. Motors that begin to show obvious decline or thermal over-stressing should be monitored more closely until the motor can be statically tested or removed from operation and repaired. New and recently repaired motors should be tested as soon as they are returned to service in order to provide a historical record (or baseline) of their performance when the motor is at its “best.”

Off-line testing

In general, motors are quite reliable, and when properly maintained, you should expect at least 100,000 hours of continual operation. That is to say, a new motor operated within nameplate parameters should give us at least 11 years of steady use. Unfortunately, motors are almost always subjected to a variety of damaging elements, with the end result being a rise in operating temperature. Thermal aging of the insulation is the major cause of insulation failure. Years of testing and numerous studies have shown that, as a “rule of thumb,” “for every 10 degrees centigrade increase in temperature, the winding life is decreased in half.”3

Besides thermal problems, other causes of insulation failures include incoming line related problems. Spikes caused by lightning and surges created by switching and contactor closing contribute to insulation breakdown. Motors also are subjected to mechanical influences including bearing failure, environmental hazards and magnet wire damage caused during the manufacturing process. Even the physical movements of the windings during startups causes wear to the insulation system, especially the magnet-wire insulation, as D.E. Crawford has shown.4

Proper testing of all components of a motor requires a series of tests designed to emulate the conditions the motor will see in the field. It has been proved in numerous studies that low-voltage testing, including capacitance, inductance, impedance, etc., are not effective tools in verifying insulation problems. Quality off-line test equipment will be able to perform winding resistance tests, insulation-resistance tests, high-potential (HiPot) tests, polarization index, and surge tests at IEEE, NEMA and EASA accepted standards. Top-quality test equipment will automatically run a series of preprogrammed tests and provide a complete final report.

This automatic equipment will stop testing before any damage is done to the windings.

The resistance test verifies the existence of dead shorts within the turn-to-turn coils and shows any imbalances between phases due to turn count differences, along with locating poor wire connections or contacts and finds open parallel coils.

DC insulation resistance testing detects faults in ground wall insulation or motors that have already failed to ground. Weak ground wall insulation (prior to copper-to-ground failure) can only be found successfully with the HiPot tests. The ground wall insulation system consists of the magnet wires insulation, slot liner insulation, wedges, varnish and often phase paper. DC HiPot test should be performed at twice line voltage plus 1,000 volts since motors will see voltage spikes of at least that level during each startup. HiPot testing is necessary to verify winding suitability for continued service.

Surge testing detects faults in both inter-turn winding and phase-to-phase insulation systems. Turn-to-turn faults will not be seen by a megger or HiPot test. Potential faults can only be seen when the coils see more than 350 volts from turn-to-turn or coil-to-coil, as described by Paschen’s Law 5 (Figure 1). The typical mechanism of fault progression is a turn-to-turn short, causing excessive heat and progressing within seconds or minutes to copper to ground faults. Faults are much more likely to occur between turn-to-turn winding coils due to the added stress caused by bending and exaggerated during the winding process. The ground wall insulation is generally many times stronger and more capable of withstanding voltage spikes and other stresses.


Figure 1.

Conclusions

Integrating on-line and off-line testing into a predictive maintenance program provides the technician with verification of his motor’s condition (see case studies below). Both technologies are necessary in order to have a complete picture of a motor’s health.

Collecting both on-line and off-line data on a routine schedule allows for early warning of impending failures and opens the opportunity window for planned downtime. Performing resistance, HiPot and surge testing along with dynamic testing provides the technician with a total picture of the motor’s condition and allows him or her to track its rate of decline.

Modern test equipment includes enhanced and detailed reporting. Reports are easily generated, providing a written hard copy of test results and making diagnosing and comparing of data clearer and more accurate. Setting up and managing a program to monitor the motors within any facility is essential to insure the safe and continued operation and production of the facility. In most cases, a properly managed and operated PMP will save a plant or facility much more than it will cost to implement, administer and manage.

Case studies

1) At a large wastewater treatment facility in Florida, 14 identical motors were scheduled for predictive maintenance. These motors were 40-horsepower aerators for a large treatment tank and operated continuously. Static tests were performed on all 14, and each received passing marks on all tests. When dynamic testing was complete, it was noted that 13 motors were acting very similar running within expected parameters at approximately 85 percent load, while the 14th motor was running at just over 30 percent load. Further inspection revealed a sheared coupling on the motor running at reduced load. The operators had no way of detecting the problem, and the location of these motors made visual inspection difficult. The dynamic testing found a problem that was costing the customer both in wasted kilowatt usage and production.

2) Twelve 60-horsepower pump/motors were tested at a large office building. Six were chilled water pump/motors and six were condenser water circulating pump/motors. All 12 were installed at the same time and ran continuously. Dynamic testing was performed one day on all 12, and all appeared to be operating within expected parameters. The motors were shut down for a scheduled annual routine building maintenance, and static testing was planned for the following morning. Resistance tests appeared normal on all, but two would not pass HiPot testing at the preset voltage. Three others failed the surge tests. The five motors were removed from service, disassembled and inspected. Two were found to be extremely dirty, while three had no visual damage. All five were reconditioned, retested and replaced in service. The off-line testing prevented five potential catastrophic failures and allowed the customer to dictate the downtime.

Source: reliableplant.com

Sunday, August 8, 2010

Embedded Condition Monitoring and Remote Diagnostics Prevent Equipment Failure, Reduce Energy Consumption, Improve Reliability

By Adam Krug


Only a very small percentage of critical motors and motor loads in the U.S. actually are equipped with any sort of condition monitoring. This lack of adoption largely stems from the costs and complexity of conventional condition monitoring equipment.

Industry-leading solid-state, motor control technology provides customers with the ability to monitor parameters, albeit not the exact same parameters, to gain a more precise and real-time perspective on performance, far more simply than traditional condition monitoring methods.

For the purposes and scope of this discussion, condition monitoring makes use of sophisticated technologies and tools to assess equipment condition, so as to predict potential equipment failure. Condition monitoring is a key element of predictive maintenance and enables scheduled maintenance. Fundamentally, it aims to prevent equipment failure and the spectrum of associated costs.

Imminent damages or failure is identified by a deviation from an established reference value. While condition monitoring does not directly predict failure, it identifies machinery or equipment that is failing or imperfect; equipment with latent problems is at greater risk for failure. Further, it is typically more cost effective to address conditions that could cause failures, rather than cleaning up once a failure has occurred.

Employing new intelligent overload relays as a supplement to traditional condition monitoring provides customers with a cost-effective means to increase the percentage of assets covered by condition monitoring within a facility. This helps end users protect more equipment from a pending motor or load failure, on loads that otherwise would have been left unmonitored. Ultimately, this means:

* Improved uptime
* Reduced maintenance costs per repair
* Reduced energy consumption

Traditional approach

Condition monitoring typically includes the following technologies: Vibration sensors, pressure transducers, RTDs and other means of measuring temperature, infrared scopes, and other various sensors to record performance data.

Traditional implementation requires sensors to be mounted on motors and pumps and then hardwired back to a device to gather the data, such as a centralized computer system. This data then needs to be interpreted by trained personnel, who are able to understand the output from these sensors. Ultimately, traditional condition monitoring methods are complex and costly.

Typically, this data is gathered continuously and logged in a central computer, or it is taken by teams of inspection crews, who record performance readings on a set schedule. In most instances, inspection crews are trained specifically on signal processing and sensor analysis and typically outsourced to a third party. Whether facilities outsource these teams to third parties or have in-house personnel dedicated to spot inspections, there are significant costs and opportunity costs associated with such methods.

Moreover, motors and pumps are not all conveniently located; many are in hard-to-access areas and can require more than one inspector to comply with OSHA regulations. When trained professionals perform their analysis from a remote location, the data is required to be streamed and passed through an IT firewall or transmitted via an outside modem.

All of that said, the traditional approach to condition monitoring can be largely effective. But, due to the costs and complexity involved, this type of attention is typically reserved for only the most critical and expensive capital equipment. Most users calculate the value of the asset as the capital costs of replacement, as well as the effect that asset has on productivity and throughput.

The lack of implementation of traditional condition monitoring despite its value is evident in a U.S. Department of Energy (DOE) study on motor monitoring practices. According to a recent study on critical loads, the U.S. manufacturing sector has nearly 32M motors rated 500 horsepower (HP) or less. Of the 141,000 motors driving pumps, fans, and compressors, only 1% has monitoring today; these are typically motors rated at 200HP or more. In other words, there are a high percentage of critical loads at low horsepower where condition monitoring is not being used. The result is unscheduled downtime or inefficient operation of equipment, which translate into:

* Reduced throughput
* Environmental fines
* Energy waste
* Higher maintenance costs
* Increased capital expenditure
* Reduced profitability

Notably, downtime costs, maintenance costs, and energy usage are critical concerns for end-users, according to an Eaton Survey. Further, according to a similar study by the DOE, there is the potential for tremendous cost avoidance; if users added monitoring to their motors and pumps, they could recognize an aggregate, annual $23 billion of energy cost avoidance.


A means for greater asset coverage


Increased adoption of advanced motor overload relays and fieldbus communications is game changing; it allows for greater system reliability and tremendous potential for cost and energy savings. The starter-based technology is “sensorless” and nonintrusive. Further, a starter is necessary with every motor installation. Simply put, advanced overload and monitoring relays provide a cost-effective solution, with greater motor coverage for condition monitoring. They yield performance data and energy usage information that can be monitored and acted upon either by personnel or control schemes within the higher level plant systems.

Maintenance optimization

With intelligent pump, motor, and line quality monitoring, customers are able to eliminate unnecessary inspections and only send personnel when data indicates an issue. With an understanding of the fault type or pending fault type, the right person with the appropriate skill set can be deployed to address specific issues. In other words, if a clog is detected, a 40-year veteran need not be sent to address the issue at hand; send individuals with appropriate experience and expertise to address defined issues. Additionally, an understanding of fault type enables personnel to come equipped with the appropriate tools; costly second trips are avoided, and service time is reduced. Simply put, optimized maintenance means:

* Scheduled downtime
* Eliminate unnecessary inspections
* Optimized labor skill sets
* Reduced service time

Armed with a remote look at the performance of their motors, customers are able to optimize maintenance and reduce costs. Motor or pump operation can be checked from any computer in a plant or facility, and even from home. Trending data collection allows for the detection or prediction of potential motor failure conditions. Further, when conditions are indicative of an imminent failure, customers are able to switch to spare or secondary motors or pumps and avoid downtime.

Low power conditions

Though much of the discussion to this point has been regarding the advanced overload relays’ ability to provide remote data monitoring, the goal of this data is to prevent failure of an asset. Overload relays can act on their own data with a high degree of flexible protection settings. One such setting not widely associated with overload relays is low power protection.

Low power conditions, where real power provided to the motor falls below normal operating conditions, can cause mechanical failure and/or excessive heating by running a pump in dead- headed or starved condition—damaging expensive seals and ultimately failing the pump. New overload relays are able to detect low power conditions with protective fault settings and avoid associated costs and downtime.

For example, an under power situation occurs when a pump continues to run against a mostly closed valve—overload relays can extend equipment life, reduce downtime, save energy, and reduce maintenance. Without the use of an advanced overload relay, the pump would continue to run because a float limit switch would not drop—as the water level would not decrease. A second pump would likely be turned on to compensate. And so, two pumps would be running and performing the work of one pump, essentially. In the meantime, the seal of the first pump would be heat-aging, shortening its usable life. Today, such a situation can be monitored, detected, and avoided. Wasted run-time hours can be avoided, with the protective-fault, under power feature. The overload relay would take the first motor offline, and the second pump would come online and complete the pumping activity—the first pump would be saved from doing non-value add work. Further, the wear on components would be reduced; the overload relay would have taken the first pump offline, preventing the heat-aging of the seal. Energy consumption would be reduced, as only one motor would be running (instead of two). Maintenance is reduced by avoiding the unnecessary use of equipment.

Driving, delivering energy savings

In the U.S., motors use approximately 71% of the electrical energy in a typical industrial facility. The large population of motors in the 20 to 300HP range are consuming the majority of the energy. Little monitoring (less than 1%) is done on low horsepower motors.

Overload relays able to monitor energy and power factor are able to:

* Avoid peak demand charges
* Shed non-vital loads
* Identify and rectify increased consumption
* Identify discrepancy between equal loads
* Identify power factor line items

Overload relays with advanced monitoring and flexible communications capabilities allow customers to observe abnormal and inefficient operation in real time. For across-the-line loads, today’s overload relays are able to do more than protect the motor. They allow customers to see consumption at the specific load and facilitate real-time equipment monitoring. Using industry protocol communications and central SCADA systems, customers can catch increased consumption in real time and control consumption and avoid downtime; situations can be rectified before extra energy costs are incurred. Commands over the fieldbus allow remote shutdown of non-vital assets, while side-by-side comparisons of similarly sized assets and comparisons made over time enable the identification of inefficiencies.

As many plants must run continuously, it is critical to be able to prevent equipment failure and scheduled downtime to address detected problems. Continuously monitoring key failure indicators with remote monitoring solutions helps facilities respond to equipment problems sooner. The early detection of system degradation—through condition monitoring and predictive diagnostics—is critical to productivity and the bottom line. To gain greater asset coverage, overload relays with advanced remote monitoring capabilities can supplement traditional condition monitoring methods—and yield significant energy and cost savings, while improving system reliability and reducing maintenance.

To meet new energy efficiency standards, many facilities will need to adopt and implement new and existing technologies, including VFDs, advanced overload relays with on-board electronic metering and monitoring, and asset management products to help make informed decisions that can improve operational efficiency. To propel energy efficiency, it is critical to provide support, education, and training for plant operators, engineers, and production workers.

Consequently, the increased demand for remote monitoring, advanced control methods, condition monitoring, and predictive diagnostics is not surprising. Customers are increasingly seeking devices that save energy, optimize their maintenance schedules, and provide greater system protection to reduce overall costs and downtime. Remote monitoring devices allow customers to monitor conditions in hard-to-access areas, trend in real-time motor conditions that could otherwise go unnoticed, and dispatch maintenance personnel before a problem occurs. Motor control system design focuses on power optimization and extended equipment life. Remote monitoring of asset conditions allows for optimal and timely predictive maintenance actions to prevent equipment failure and inefficient operation.

Source: www.isa.org

Friday, August 6, 2010

Vibration Testing and Thermal Imaging Technology

Here's an article about vibration testing technology and thermal imaging technology. I find it really amazing hearing some companies using it and living through it, keeping it as part of their predictive maintenance technology in their manufacturing and operation.

Vibration Testing Technology

To the savvy maintenance professional, industrial machinery almost "talks" to reveal its condition. The key to success is in understanding what the machine is saying. To detect problems, the professional "listens" in many ways: With eyes and ears, to see and hear conditions that may indicate problems and...

  • With thermometers and thermal imagers, to detect overheating, poor electrical connections or failing bearings
  • With digital multimeters and power analyzers, to diagnose electrical problems
  • Using techniques like lubricant analysis, to gauge machine condition over time

And now new vibration testing tools provide the maintenance professional with a valuable new way not just to listen, but to find mechanical problems and fixes: these new troubleshooting tools are engineered to detect and evaluate machine vibration immediately and recommend any needed repairs.

A new kind of troubleshooting tool

Many industrial maintenance teams today work under severe restrictions on money and time. They may not have the resources to train for and implement the typical long-term vibration analysis program. Further, many professionals may think there are only two options for vibration testing; high-end vibration analyzers that are expensive and difficult to use, and low-end vibration pens, which aren't particularly accurate.

Fortunately, a new breed of vibration-testing tool fills the middle of the category, combining the diagnostic capability of a trained vibration analyzer with the speed and convenience of lower-end testers, at a reasonable price. This type of tool is designed to be not merely a vibration detector, but a complete diagnostic and problem-solving solution, and targeted specifically for maintenance professionals who need to troubleshoot mechanical problems and quickly understand the root cause of equipment condition.

These tools are designed and programmed to diagnose the most common mechanical problems of unbalance, looseness, misalignment and bearing failures in a wide variety of mechanical equipment, including motors, fans, blowers, belts and chain drives, gearboxes, couplings, pumps, compressors, closed coupled machines and spindles.

Not just data, but actionable results

When these new testers detect a fault, they identify the problem, its location and severity on a multi-level scale to help the maintenance professional prioritize maintenance tasks. They may also recommend repairs.

Mechanical diagnosis can begin with the user placing the device's accelerometer on the machine under test. The accelerometer may have a magnetic mount or can be installed using adhesive. As the machine under test operates, the accelerometer detects its vibration along three planes of movement (vertical, horizontal and axial) and transmits that information to the tester. Using a set of advanced algorithms, the tester then provides a plain-text diagnosis of the machine with a recommended solution.

No training? No problem

Mechanical equipment is typically evaluated by comparing its condition over time to an established baseline condition. Vibration analyzers used in condition-based monitoring programs rely upon these baseline conditions to evaluate machine condition and estimate remaining operating life. System operators must have considerable training and experience before they can determine the meaning and significance of the vibration spectra they detect.

But what about the maintenance pro who isn't trained in vibration analysis? How do you tell the difference between acceptable vibration, and the kind of vibration that demands immediate attention to service or replace troubled equipment?

Fortunately, extensive experience with mechanical vibration, what it means and how to fix it is built into the advanced algorithms of today's testers. Now the maintenance professional can quickly and reliably determine the cause of the machine vibration, learn the severity and location of the problem and receive recommendations for repair. It's all done with the intelligence built into the tester, without the extensive training, monitoring and recording required for typical vibration monitoring programs.


Now Lets talk about things about thermal imaging technolgy.



About the Thermal Image Camera


Having a thermal image camera can be quite beneficial. There are a lot of individuals who are opting for thermal imaging nowadays. Thermal imaging is quite great for analysis and problem solving. The great thing about thermal image camera is that it is quite easy to carry with you and it gives great performance. This can be attributed to the fact that it produces great thermal pictures due to its high resolution thermal detectors. It can be like having a normal digital camera but with more benefits.

When you are planning to purchase your own camera that has thermal imaging one has to consider some pointers in finding a quality one. One has to look a camera that has a high resolution. It is also wise to note the pixels output of the camera. This feature is very important for the temperature ability of the camera.

Secondly, accuracy should be an important feature of your choice of camera. An accuracy of 3% to 5% is what you should look for. Another feature that should consider is its temperature range. You have to take into account the weather conditions in your area. Whether you a hot or cold climate, this can really create a problem with the pictures it will produce.

A camera that has thermal imaging is being widely used by law enforcers. It helps them detect things that are quite seen by the human eye and this is a valuable asset for the law enforcement departments. Even plumbing and pest control areas have a great use for this type of camera. It helps them detect problems where they can not quite see or is obstructed from view.

Of course, the price of a thermal imaging camera is an important factor in buying it. You can usually buy a camera that has thermal imaging at around $3000. This is the model that is being used by a lot of professionals. The more features it has would mean that it would be more expensive. The best thing to do is to do a little bit of research and do price comparisons. You can great deals and bargains if you know where to look.

Source: Zara Jones and Steve Glad

Tuesday, January 19, 2010

Can smart instruments help Predictive Maintenance?

Predictive Maintenance do really needs modern instrument or can smart instruments really help Predictive Maintenance? This question pulls together the entirely unrelated concepts of smart instruments, and predictive maintenance. The smart instruments (sometimes also called “smart sensors”) concept is a hardware-architecture strategy. Predictive maintenance, on the other hand, is a system-level concept.

Smart instruments have been around for a decade or more. The technology falls under the general heading of “embedded systems,” which includes any device containing a microcomputer, but no fully developed user interface. Examples include automotive engine control modules (ECMs); microprocessor controls for major appliances, such as dishwashers, microwave ovens, etc.; and mobile systems, such as cellphones and digital cameras. Smart instruments include one or more sensors to make physical measurements, a microprocessor to partially analyze sensor data, on-board memory to hold parameters and intermediate results, and I/O capabilities to report results to the next level of automation. Components for such devices are packaged together and mounted as close as possible to the point of measurement.

Predictive maintenance strategies monitor selected variables that engineers believe have maintenance-predictive power. For example, a rise in a bearing’s temperature may warn of impending need for additional or replacement lubricant. Automatically monitoring such variables makes it possible for the system to tailor the maintenance program to the machinery’s actual needs, saving time, supplies, and replacement parts, and avoiding unplanned work stoppages. The alternative is scheduled maintenance, which generally provides more maintenance than necessary on average, but may miss extraordinary events.

For example, a system described by engineers at SKF provides automatic bearing lubrication based on predictive maintenance principles. Traditional scheduled-maintenance calls for a technician to apply a certain amount of oil at set intervals. The schedule is (theoretically) based on historical data about how rapidly that type of bearing uses lubricant under the prevailing use conditions. Being statistical in nature, that data may over- or under-predict the needs of a particular bearing. In addition, even experienced technicians tend to apply more lubricant than necessary, which can actually harm the equipment. Failures can occur when the particular bearing uses lubricant at a rate significantly slower or faster than average. In the first case, too much lubricant would be applied. In the second, too little.

Physical phenomena associated with impending requirements for bearing lubrication are temperature rise and increased bearing noise (vibration). A smart instrument monitoring bearing temperature and noise can tailor the maintenance program to the particular bearing. It can automatically report a pattern of increasing operating temperature coupled with increased bearing noise appears. Maintenance personnel can then use this information to predict when lack of lubrication will begin damaging the bearing, and schedule a technician to apply lubricant just ahead of the danger point. This manual system reduces lubricant requirements, protects equipment more effectively, and reduces unscheduled downtime. Because maintenance operations still occur infrequently (typically at longer intervals than with scheduled maintenance because safety margins can be reduced), however, more lubricant than necessary is typically added at each maintenance, leading to some waste.
Smart-instrument-based predictive maintenance
Smart sensors can help make an automated system for bearing lubrication.

In SKF’s automated system, maintenance personnel do not schedule the lubrication visit, but the condition-monitoring computer automatically controls a microvolume pump to add oil in small quantities until the temperature and noise begin to trend down. When these parameters drop within specifications, the pump stops adding lubricant. This strategy applies just the needed lubrication when it’s needed, independent of the bearing’s peculiarities. By adding lubricant frequently in very small quantities, it is possible to keep the lubricant level very close to optimum. This reduces waste to a minimum by virtually eliminating overlubrication, and eliminates downtime for lubrication entirely.

The automated bearing lubrication system is just one example of a well-developed automated system based on predictive maintenance principles. Predictive maintenance systems based on monitoring physical parameters are actually quite common today. As embedded system techniques and smart sensors become more common in control applications, look for more instances of automated maintenance systems.

Source: www.controleng.com/blog | August 18, 2008

Sunday, January 17, 2010

5S Process in Reliability Improvement

The 5-S process is a method for ensuring workplace cleanliness, order and organization and should be at the heart of any reliability improvement initiative. It consists of five fundamental steps:
  1. Sort— Get rid of accumulated junk that has no value to the job at hand. In Maintenance, this includes removing everything that does not add value to the work being done — components from broken machinery, unrepaired spare assemblies and tools, obsolete charts and graphs and "abandoned-in-place" equipment and piping systems. If it is not needed for the job at hand, it needs to be eliminated.
  2. Straighten— Organize what remains after the first step. Consider the flow of work through the area and position equipment and storage facilities to eliminate lost motion and wasted travel. A craftsperson should not have to search for a tool or move something out of the way to begin work.
  3. Scrub/Shine— Workplace cleanliness is the next step. Precision work requires a clean work environment. Shop spaces used to rebuild equipment should approach "clean room" standards. Remove all dust, dirt and contamination. Seal concrete floors so that spills are easily cleaned. Repair lighting fixtures and paint the work area with light colors — a brightly lit work environment is much more likely to remain clean. Deteriorating equipment conditions are more easily spotted when not covered by contamination.
  4. Standardize— When the workplace is clean and organized, it must be kept that way. A system should be put into place that ensures the condition of the work area does not degrade. Visual controls can be used at the equipment level — registration marks on fasteners, color coding correct operating ranges on gauges and matched marking assemblies are examples.
  5. Sustain— A process for conducting audits on a regular basis should be considered. When management shows a concern for workplace condition, it is much more likely to remain in good shape. Every employee must understand the need for safety, order and cleanliness. The facility should be kept in "tour condition" at all times.

The cleanliness must be performed so you won’t have to work in an unsafe, disorganized area which puts you at risk or even in danger. Since 5-S is for you, you also have an obligation and the responsibility to help prepare the tools and make sure they are in the proper place so that you can begin your job on time and efficient. Clean-up and organize your work area every day so that each new day is easier and safer than the day before. Share your input with your leaders so that the tools you need will be available to you, increasing your efficiency. Volunteer to help with the 5-S tours and resolve issues that are noted.

Thursday, January 14, 2010

Total Productive Maintenance Implementation

To begin applying TPM concepts to plant maintenance activities, the entire work force must first be convinced that upper level management is committed to the program. The first step in this effort is to either hire or appoint a TPM coordinator. It is the responsibility of the coordinator to sell the TPM concepts to the work force through an educational program. To do a thorough job of educating and convincing the work force that TPM is just not another "program of the month," will take time, perhaps a year or more.

Once the coordinator is convinced that the work force is sold on the TPM program and that they understand it and its implications, the first study and action teams are formed. These teams are usually made up of people who directly have an impact on the problem being addressed. Operators, maintenance personnel, shift supervisors, schedulers, and upper management might all be included on a team. Each person becomes a "stakeholder" in the process and is encouraged to do his or her best to contribute to the success of the team effort. Usually, the TPM coordinator heads the teams until others become familiar with the process and natural team leaders emerge.

Total Productive Maintenance action teams are charged with the responsibility of pinpointing problem areas, detailing a course of corrective action, and initiating the corrective process. Recognizing problems and initiating solutions may not come easily for some team members. They will not have had experiences in other plants where they had opportunities to see how things could be done differently. In well run TPM programs, team members often visit cooperating plants to observe and compare TPM methods, techniques, and to observe work in progress. This comparative process is part of an overall measurement technique called "benchmarking" and is one of the greatest assets of the TPM program.

TPM teams are encouraged to start on small problems and keep meticulous records of their progress.
Successful completion of the team's initial work is always recognized by management. Publicity of the program and its results are one of the secrets of making the program a success. Once the teams are familiar with the TPM process and have experienced success with a small problem, problems of ever increasing importance and complexity are addressed.

As an example, in one manufacturing plant, one punch press was selected as a problem area. The machine was studied and evaluated in extreme detail by the team. Production over an extended period of time was used to establish a record of productive time versus nonproductive time. Some team members visited a plant several states away which had a similar press but which was operating much more efficiently. This visit gave them ideas on how their situation could be improved. A course of action to bring the machine into a "world class" manufacturing condition was soon designed and work was initiated. The work involved taking the machine out of service for cleaning, painting, adjustment, and replacement of worn parts, belts, hoses, etc. As a part of this process, training in operation and maintenance of the machine was reviewed. A daily check list of maintenance duties to be performed by the operator was developed. A factory representative was called in to assist in some phases of the process. Total Productive Maintenance was just the right fit for the situation

After success has been demonstrated on one machine and records began to show how much the process had improved production, another machine was selected, then another, until the entire production area had been brought into a "world class" condition and is producing at a significantly higher rate.

Note that in the example above, the operator was required to take an active part in the maintenance of the machine. This is one of the basic innovations of TPM. The attitude of "I just operate it!" is no longer acceptable. Routine daily maintenance checks, minor adjustments, lubrication, and minor part change out become the responsibility of the operator. Extensive overhauls and major breakdowns are handled by plant maintenance personnel with the operator assisting. Even if outside maintenance or factory experts have to be called in, the equipment operator must play a significant part in the repair process. Training for TPM coordinators is available from several sources. Most of the major professional organizations associated with manufacturing as well as private consulting and educational groups have information available on TPM implementation. The Society of Manufacturing Engineers (SME) and Productivity Press are two examples. Both offer tapes, books, and other educational material that tell the story of TPM. Productivity Press conducts frequent seminars in most major cities around the United States. They also sponsor plant tours for benchmarking and training purposes.

Wednesday, January 13, 2010

Total Productive Maintenance History


Total Productive Maintenance (TPM) evolved from Total Quality Management (TQM,) which evolved as a direct result of Dr. W. Edwards Deming's influence on Japanese industry. Dr. Deming began his work in Japan shortly after World War II. As a statistician, Dr. Deming initially began to show the Japanese how to use statistical analysis in manufacturing and how to use the resulting data to control quality during manufacturing. The initial statistical procedures and the resulting quality control concepts fueled by the Japanese work ethic soon became a way of life for Japanese industry. This new manufacturing concept eventually became knows as Total Quality Management or TQM.


When the problems of plant maintenance were examined as a part of the TQM program, some of the general concepts did not seem to fit or work well in the maintenance environment. Preventative maintenance (PM) procedures had been in place for some time and PM was practiced in most plants. Using PM techniques, maintenance schedules designed to keep machines operational were developed. However, this technique often resulted in machines being over-serviced in an attempt to improve production. The thought was often "if a little oil is good, a lot should be better." Manufacturer's maintenance schedules had to be followed to the letter with little thought as to the realistic requirements of the machine. There was little or no involvement of the machine operator in the maintenance program and maintenance personnel had little training beyond what was contained in often inadequate maintenance manuals.

The need to go further than just scheduling maintenance in accordance with manufacturer's recommendations as a method of improving productivity and product quality was quickly recognized by those companies who were committed to the TQM programs. To solve this problem and still adhere to the TQM concepts, modifications were made to the original TQM concepts. These modifications elevated maintenance to the status of being an integral part of the overall quality program.

The origin of the term "Total Productive Maintenance" is disputed. Some say that it was first coined by American manufacturers over forty years ago. Others contribute its origin to a maintenance program used in the late 1960's by Nippondenso, a Japanese manufacturer of automotive electrical parts. Seiichi Nakajima, an officer with the Institute of Plant Maintenance in Japan is credited with defining the concepts of TPM and seeing it implemented in hundreds of plants in Japan.

Books and articles on TPM by Mr. Nakajima and other Japanese as well as American authors began appearing in the late 1980's. The first widely attended TPM conference held in the United States occurred in 1990. Today, several consulting companies routinely offer TPM conferences as well as provide consulting and coordination services for companies wishing to start a TPM program in their plants.

Tuesday, January 12, 2010

Lean maintenance and its many faces


What Lean Maintenance is all about?


Lean Maintenance is the application of Lean philosophy, tools and techniques to the maintenance function. It has the same goals as the application of Lean principles to the manufacturing function: eliminating wasted time, effort and material (and resulting cost) while improving throughput and quality.

As Lean Manufacturing seeks to provide products at the highest quality at the lowest cost in the shortest possible time, Lean Maintenance provides the same attributes to the maintenance function. In fact, Lean Manufacturing depends highly on reliable systems and equipment to achieve its potential.

Lean does not imply cutting the fat or eliminating jobs. It is not an attempt to reduce cost through headcount reductions, which typically don't have anything to do with reducing work. Lean organizations reduce costs by eliminating activities that don't add value to the product stream. It means reassigning people and resources from unnecessary work to value-adding work.

Many tools used to implement Lean principles in manufacturing operations also apply to implementing Lean Maintenance. These tools include:

• 5-S process
• Elimination of the Seven Deadly Wastes
• Kaizen
• Jidoka (Quality at the Source)
• JIT (Just in Time).

I came across in this article some years ago, I think that was 2005. That was during the time I am searching about Lean Maintenance. I like the idea on Lean Maintenance but I never heard this term (Lean Maintenance) in our company department but I assure that we're practicing its application.

Source: Bruce Hawkins, CMRP, CPMM, Life Cycle Engineering | Plant Engineering

Thursday, January 7, 2010

Successful Predictive Maintenance (PdM) Programs Depend on Consistency


The following is an except from the article entitled "Choose Your PdM Partners Wisely Or Discover Another Reason Why PdM Programs Can Fail" by Alan Friedman, appeared on reliabilityweb.com

One reason many in-house programs fail is a lack of consistency on many levels. A successful Predictive Maintenance (PdM) program relies on long-term consistency on the technical level in terms of collecting repeatable data for trending. This means that assets must be tested the same way time after time, year after year, in terms of test speeds, loads, test positions, test types etc. Consistent testing ensures accurate trending of machine condition, the development of meaningful baselines and alarm criteria and, therefore, accurate fault diagnosis and repair recommendations. This is very different from the process of using the technology to troubleshoot an asset. Troubleshooting is a valid use of these technologies, but does not result in a change in maintenance philosophy, nor does it provide the large ROI’s such a change in philosophy should produce.


On a higher level, such technical consistency also depends on the reliability of management and personnel. Oftentimes, due to lack of financial justification, PdM programs are stopped and personnel are reassigned to different tasks. New maintenance managers may not understand the technology and may recommend a new approach to using – or not using – it which disrupts the consistency of a program. In-house “experts,” in seeking to keep their jobs secure, may not document or follow fixed procedures for monitoring equipment or share information with others, causing programs to fail when they leave for greener pastures.


There are many reasons why programs bloom and then decay. People who have different ideas about how Predictive Maintenance (PdM) should be done come and go, priorities change, technology changes, expertise changes and approaches change. The one sure thing is that all of these starts and stops and changes in direction ensure a program will never be successful. This is another reason why an external partner is a good option to keep the program running steadily regardless of what is happening within the maintenance department of your facility.


In general, it can be said that a good Predictive Maintenance program requires a consistent approach, with a clear set of objectives that can be measured to monitor the success or failure of the program. The program must continue to remain consistent through good times and bad, regardless of who in the facility (or outside the facility) is running the program, collecting data, analyzing it or writing reports. This sort of consistency is often difficult to maintain within a facility, and is an example of where a good partnership with a Predictive Maintenance service provider can be a huge asset. Especially if this partner has a long track record of managing successful PdM programs and has a well-defined approach to managing such programs. This is different from hiring a vibration expert to come on-site at times to troubleshoot machines or structures.


But why choose your Predictive Maintenance (PdM) partners wisely? Here's his conclusion:

Whether you are considering starting a new program, revamping a dead one, outsourcing or looking for someone to become a long term partner to step in when needed and step back when not needed, make sure you pick the correct partner. The company should have a good track record of managing successful programs, should use good equipment for the job, and should make necessary equipment available to you as part of a sale or service or as a lease as needed. Make sure your partner can train staff at all levels, from using the products to analyzing graphs, but, more importantly, is capable of managing your particular program and answering specific questions related to auditing your program. The importance of helping you calculate the economic impacts of these technology and maintenance practices to your bottom line can not be underestimated.

More than anything, consider that choosing the right partner may make the difference between a consistent and effective program that runs smoothly over the next ten or twenty years and an endless series of false starts and investments in misused equipment. One thing is for sure, successful programs, more often than not, involve good partners.

To read the full article click here:
Choose Your PdM Partners Wisely

Wednesday, January 6, 2010

Reliability Centered Maintenance Advantage and Disadvantages

Reliability centered maintenance (RCM) is the maintenance approach used when following a process that assesses equipment condition and determines the maintenance requirements of any physical asset in its operating context.

Basically, the RCM methodology addresses key issues not dealt with by other maintenance programs. This approach recognizes that all equipment in a facility is not of equal importance—to either the process or to facility needs and safety. Focusing on reliability of equipment means recognizing that equipment design and operations differ, and that each piece of equipment will have a different probability of undergoing failure from degradation than will another. A reliability-focused approach will mean structuring a maintenance program based upon the understanding of equipment needs and priorities, as well as limited financial and personnel resources, to plan activities such that equipment maintenance is prioritized while operations are optimized.

Simply put, RCM is a systematic approach of evaluating a facility's equipment and resources to best match the two needs. This results in a high degree of facility reliability and cost-effectiveness, and is highly reliant on predictive maintenance. However, it also recognizes that maintenance activities on equipment that is inexpensive and less important to overall facility reliability may be best left to a reactive maintenance approach, focusing both labor and financial resources on higher priority and more costly equipment. The following maintenance program breakdowns of continually top-performing facilities echo the RCM approach, which utilizes all available maintenance tactics. As is shown, all maintenance approaches are used, but the predominant strategy used is predictive.
  • <10%>
  • 25% to 35% Preventive
  • 45% to 55% Predictive
Because RCM is so heavily weighted on utilization of predictive maintenance strategies, its program advantages and disadvantages mirror those of predictive maintenance. In addition to these advantages, RCM will allow a facility to more closely match its resources to operational needs and at the same time improve both reliability and also reduce associated maintenance costs.

Advantages
  • Can be the most efficient maintenance program
  • Lowers costs by eliminating unnecessary equipment maintenance or system overhauls
  • Minimizes the frequency of overhauls
  • Reduces probability of sudden equipment failures
  • Focuses maintenance activities on critical system components
  • Increases component reliability
  • Incorporates root cause analysis
Disadvantages
  • Can have significant startup costs associated with staff training and equipment needs
  • Savings potential is not readily seen by management

An Introduction to Total Productive Maintenance (TPM)


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 Total Productive Maintenance?
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 Total Quality Management (TQM) and Total Productive Maintenance (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.

TQM
Object: Quality ( Output and effects )
Mains of attaining goal: Systematize the management. It is software oriented
Target: Quality for PPM

TPM
Object:
Equipment ( Input and cause )
Mains of attaining goal:
Employees participation and it is hardware oriented
Target:
Elimination of losses and wastes.

Source: plant-maintenance.com | Venkatesh J

Tuesday, January 5, 2010

Predictive Maintenance Implementation: Advantages and Disadvantages

A predictive maintenance approach strives to detect the onset of equipment degradation and to address the problems as they are identified. This allows casual stressors to be eliminated or controlled, prior to any significant deterioration in the physical state of the component or equipment. This leads to both current and future functional capabilities.

Basically, predictive maintenance differs from preventive maintenance by basing maintenance needs on the actual condition of the equipment, rather than on some predetermined schedule. Recall that preventive maintenance is time-based. Activities such as changing lubricant are based on time, like calendar time or equipment run time. For example, most people change the oil in their vehicles every 3,000 to 5,000 miles traveled. This is effectively basing the oil change needs on equipment run time. No concern is given to the actual condition and performance capability of the oil. It is changed because it is time.

This methodology would be analogous to a preventive maintenance task. If, on the other hand, the operator of the car discounted the vehicle run time and had the oil analyzed at some periodicity to determine its actual condition and lubrication properties, he or she may be able to extend the oil change until the vehicle had traveled 10,000 miles. This is the fundamental difference between predictive maintenance and preventive maintenance, whereby predictive maintenance is used to define needed maintenance tasks based on quantified material and equipment condition.

Advantages
  • Provides increased component operational life and availability
  • Allows for preemptive corrective actions
  • Results in decrease in equipment and/or process downtime
  • Lowers costs for parts and labor
  • Provides better product quality
  • Improves worker and environmental safety
  • Raises worker morale
  • Increases energy savings
  • Results in an estimated 8% to 12% cost savings over which might result from a predictive maintenance program
Disadvantages
  • Increases investment in diagnostic equipment
  • Increases investment in staff training
  • Savings potential is readily seen by management
There are many advantages of using a predictive maintenance program. A well-orchestrated predictive maintenance program will all but eliminate catastrophic equipment failures. Staff will then be able to schedule maintenance activities to minimize or eliminate overtime costs. And, inventory can be minimized, as parts or equipment will not need to be ordered ahead of time to support anticipated maintenance needs. Equipment will be operated at an optimal level, which will also save energy costs and increase plant reliability.

Past studies have estimated that a properly functioning predictive maintenance program can provide a savings of 8% to 12% over a program utilizing preventive maintenance strategies alone. Depending on a facility's reliance on a reactive maintenance approach and material condition, savings opportunities of 30% to 40% could easily be realized. In fact, independent surveys indicate the following industrial average savings resulted from initiation of a functional predictive maintenance program:
  • 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%
The down side of using a predictive maintenance approach are its initial costs. The up-front costs of starting this type of program can be expensive. Much of the equipment requires expenditures in excess of $50,000. And, training of in-plant personnel to effectively utilize predictive maintenance technologies and practices will require substantial additional funding. And, beginning a predictive maintenance program requires an understanding of the facility's predictive maintenance needs and the approaches which need to be undertaken. It is also essential to have a firm commitment, by management and all facility staff and organizations, to make it work.

Monday, January 4, 2010

Preventive Maintenance (PM) Definition

Preventive Maintenance

Preventive maintenance (PM) has the following meanings:

  1. The care and servicing by personnel for the purpose of maintaining equipment and facilities in satisfactory operating condition by providing for systematic inspection, detection, and correction of incipient failures either before they occur or before they develop into major defects.
  2. Maintenance, including tests, measurements, adjustments, and parts replacement, performed specifically to prevent faults from occurring.

While preventive maintenance is generally considered to be worthwhile, there are risks such as equipment failure or human error involved when performing PM, just as in any maintenance operation. PM as scheduled overhaul or scheduled replacement provides two of the three proactive failure management policies available to the maintenance engineer. Common methods of determining what PM (or other) failure management policies should be applied are; OEM recommendations, requirements of codes and legislation within a jurisdiction, what an "expert" thinks ought to be done, or the maintenance that's already done to similar equipment. However Reliability Centered Maintenance, provides the most rigorous and method to determine applicable and effective failure management policies - which may include PM tasks - for an item.

Preventive Maintenance

To make it simple:
  • Preventive maintenance is conducted to keep equipment working and/or extend the life of the equipment.
  • Corrective maintenance, sometimes called "repair", is conducted to get equipment working again.

The primary goal of maintenance is to avoid or mitigate the consequences of failure of equipment. This may be by preventing the failure before it actually occurs which PM and condition based maintenance help to achieve. It is designed to preserve and restore equipment reliability by replacing worn components before they actually fail. Preventive maintenance activities include partial or complete overhauls at specified periods, oil changes, lubrication and so on. In addition, workers can record equipment deterioration so they know to replace or repair worn parts before they cause system failure. The ideal preventive maintenance program would prevent all equipment failure before it occurs.

Source: wikipedia

Predictive Maintenance Program

A Quality Rotating Machinery Predictive Maintenance (PdM) Program for your facility will return your investment many times over. This type of PdM Program is based on periodic vibration measurements of your Rotating Machinery. In many cases, a Return On Investment (ROI) of less than one year (six months typical) is quite common. A Contract PdM Program eliminates the initial capital investment required to conduct your own PdM Program.

There are three classifications of machinery maintenance methods: Breakdown, Preventative, and Predictive Maintenance. Each method has its own associated costs and benefits.

Breakdown Maintenance, by its own nature, is the most expensive method of plant maintenance. This method has no scheduled maintenance until a machine destroys itself, and it must be replaced at great cost. The machine breakdown often brings the production process to an immediate halt. Breakdown Maintenance has high costs in manpower, replacement parts, and lost production.

Preventive Maintenance, the next logical method, relies on a periodic inspection the machines. During the inspection, machine damage is found and corrected. This method requires a large inventory of replacement parts prior to the machine's inspection. Preventative Maintenance has a lower associated cost because manpower can be planned in advance.

Predictive Maintenance involves monitoring the machine's vibration characteristics or symptoms to diagnose its condition. This method relies on the machine's condition to accurately schedule the repair interval. The machine's condition also determines the required replacement parts. Predictive Maintenance has the lowest cost of the three methods with the highest possible savings.

A Machinery PdM Program is beneficial to all industries that have rotating machinery on their site such as:
  • Petroleum
  • Chemical
  • Power Generation
  • Co-Generation
  • Pulp and Paper
  • Water Treatment
  • Building Services
  • HVAC
  • Mining
  • Food Processing

Typical Rotating Machinery commonly included in a Machinery PdM Program include but are not limited to the following:
  • Electric Motors
  • Pumps
  • Fans
  • Gear Boxes
  • Turbines
  • Compressors
  • Paper Machines
  • Reciprocating Machines
  • Blowers
  • Machine Tools
  • Chillers
  • Conveyors

Sunday, January 3, 2010

Vibration Analysis as Prognostic Maintenance Procedure

Vibration analysis is becoming more and more well-known as a prognostic maintenance procedure as well as a support for machinery maintenance judgment and decisions. Generally, machines don't fail, malfunction, or break down without showing some symptoms or warning, which is often shown by an amplified level of vibration. To find out the nature and harshness of the machine flaw, and to therefore predict the failure of the machine or equipment, vibration measurement and analysis should be conducted.

A machine has an overall vibration signal that comes from the several components and structures infused into it. Mechanical problems, however, create distinctive vibrations at varying frequencies. And these defects as well as the natural frequencies of different structural elements can be diagnosed by analyzing the frequency and time range and employing signal processing skills.

Since vibration analysis deals with all moving components of any kind of rotating device, it can point out not just particular machine troubles but can also make repairs simpler by spotting the origin or root cause of the problem. And most significantly, vibration analysis is capable of discovering the flaws before they become evident. Hence, you will be warned of budding equipment problems, and you can allow your engineers or technicians to be ready for repairs and to make the repairs at a convenient time rather than during emergency situations.

Vibration analysis, which is done through a vibration analyzer, and some skill, can help a person point out the causes of coarse and irregular machinery conditions. Vibration analysis systems are really helpful for modal analysis and vibration testing.

When it comes to analysis requirements, vibration analysis is complicated and calls for human experience and capability. Nevertheless, it is an inexpensive and functional diagnostic means to guarantee a smoothly running machine.

Source: Ezinearticles | Elizabeth Morgan

Saturday, January 2, 2010

Predictive and Preventive Maintenance in a Declining Economy

In a declining economy saving operating expenses has become a priority for most firms. Predictive and preventive maintenance although similar, are two different tools used by facilities managers in order to save precious dollars. Both maintenance systems help keep earnings (the bottom line) stable by avoiding costly repairs and maximizing equipment up-time. Normally cutting expenses for operations means fewer support staff, hiring freezes, and a repair versus replacement strategy on equipment. But what happens when the forecast for low or declining sales does not improve or is mired in a deep recession?

A recent survey conducted by Facilities Planners and Architects, Inc. of facility managers and business owners revealed intended reactions to the current economic situation. The survey highlights are:

  • Limiting capital expenditures to sustainability initiatives such as more efficient lighting systems
  • More plans to reduce square footage
  • Outsourcing non-core services such as janitorial services
  • Assessing the condition of the facilities and better strategic planning of their use
  • Initiating predictive maintenance programs

Obviously, it is always a good idea to watch your expenses. The results echoes this and indicates a long overdue desire to become more energy efficient, a focus on core responsibilities by outsourcing non-core functions, a strategic look at assets and the initiation of efficiency and savings programs. The survey mentions predictive maintenance as one of the most popular choices for cost saving solutions. It should be noted that predictive maintenance is not the same as preventive maintenance. Successful predictive maintenance starts with preventive maintenance. To better understand let us take a look at both.

Predictive vs. Preventive Maintenance:

Preventive maintenance occurs on a pre-determined schedule and is intended to increase efficiencies by reducing the amount of reactive work and increasing the ability of management to manage work. Most importantly, it allows for the early identification of problems and significantly increases the life cycle of equipment, lowers capital expenditure requirements and allows for better planning of capital budgets. In addition, when integrated with handheld technologies and a combination of asset management, work order management and inspections, work flow efficiencies are increased to maximum levels. The data collected through this method becomes the building block for predictive maintenance.

Predictive maintenance does have its benefits in a difficult economy particularly because it can be less labor intensive than preventive maintenance. Predictive maintenance programs are based upon the actual condition of the equipment and a determination of when maintenance should be performed to minimize costs. New technology techniques such as ultrasound, infrared and vibration online testing make predictive maintenance a viable alternative in certain circumstances. However, for most equipment the complex metrics for making educated guesses is provided by preventive programs.

The goal of a facility manager or business owner is to make sure equipment has the highest possible uptime and to extend the life cycle of the equipment as long as possible at the most reasonable economical cost. Some predictive maintenance plans will require a capital investment in higher technology sensing equipment but most will be built upon the foundation and metrics provided by an existing preventive maintenance program. Facility managers should not rely on just a predictive maintenance solution to save expenses especially if dealing with high value equipment or if safety is at stake.

Tough times call for tough decisions as both maintenance programs have their place. The solution may be a combination of the two maintenance programs or it may be dependent on your industry, type of equipment and survival strategy. What is your company going to do?

Source: Mintek | http://EzineArticles.com/?expert=S_W_Smith

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