Monday, October 26, 2009

Equipment Maintenance Management Software

The strategic goal of any production and utilities department is to maximize production. Machinery and equipment is run continuously, or in batches. The equipment can be complex, as in nuclear reactors, or as simple as lathe machines. The goal to maximize production is determined by the availability of the equipment and its condition.

The strategic goal of the maintenance department servicing production and utilities departments is to ensure the reliability and availability of the machines. The operational goals of the maintenance department require availability and scheduling of employees for work orders, maintaining inventories for the parts, and the analysis of maintenance-related problems.

Equipment maintenance management software helps achieve the strategic and operational goals of a maintenance organization. These software packages are available as stand-alone applications customized for specific requirements, or integrated end-to-end solutions.

At the strategic level, equipment MMS helps top management to make decisions about the purchase of equipment by providing data and analysis of the cost of managing the assets, and by providing data about the vendor and analysis of the equipment provided by various vendors.

At the operations level, equipment MMS helps manage the maintenance schedule of the equipment. The software helps in the preventive and predictive maintenance by analyzing the historic data of the previous maintenance work orders. It also helps decide the availability of the equipment and the duration of the work. An integrated solution helps in optimizing the inventories by determining the parts usage and reorder time.

Equipment MMS is ideally suited for small and medium-sized enterprises for which the entire integrated solutions may be very expensive. The decision to install equipment MMS should be guided by the requirements of the organizations and the features of the software.

Develop Good Strategies For Effective Preventive Maintenance (2/2)

A second and more dominant area of confusion occurs when a scheduled task reveals unacceptable equipment deterioration (like the problem above in the MO situation, except it was not unexpected since a PM task discovered its presence). So actions are taken to repair/restore the full functionality before an unexpected operational impact can occur. Is the repair/restore action preventive or corrective?

If you will recall that the purpose of the PM task is to perform actions that will retain functional capabilities, then the answer is essentially self evident — the repair/restore action is preventive. Why? Because a proper structuring of the PM task will always include not only the search for equipment condition, but also the requirement to do something about it if the search uncovers a problem.

This search includes PM tasks that require inspection, monitoring parameters that detect failure onset, discovery of hidden failures and even restoration of equipment that was deliberately allowed to run to failure. Unfortunately, though, many CMMS programs will not allow the user to create or code a new work order to cover the emergent work as PM. This additional PM work can only be coded as CM. This inflates the cost of CM, and can lead management to question why CM costs are increasing even when their PM program had been recently improved.

As a general rule, corrective maintenance is more costly than preventive maintenance. If anyone should doubt this, then just compare two similar plants or systems where one has a proactive maintenance program and the other a reactive maintenance program. Which one do you think has the lower overall maintenance cost and higher availability?
Why do preventive maintenance?

For the past 15 years, as part of our seminars and client training programs, we frequently ask the question "Why do preventive maintenance?" The answers that we consistently hear reflect the popular belief that PM is done for a rather narrowly defined reason and this, as such, leads to the exclusion of a number of golden opportunities for PM enhancement.

So why do you do preventive maintenance? The overwhelming majority of maintenance and plant engineering personnel will respond "To prevent equipment failures." Would that have been your response? If so, you are correct — but not complete in your viewpoint. Unfortunately, we are not yet smart enough to prevent all equipment failures. But that does not mean that our ability to perform meaningful preventive maintenance tasks must end there.

In fact, there are three additional and important options to consider. First, while we may not know how to prevent a failure, frequently we do know how to detect the onset of failure. And our knowledge of how to do this is increasing every day, and is creating a whole new discipline called predictive maintenance. Second, even though we may not be able to prevent or detect the onset of failure, we often can check to see if a failure has occurred before equipment is called into service. Various standby and special purpose equipments (whose operational state is often hidden from the operator's view until it is too late) are candidates for this area. Thus, discovery of hidden failures is yet another PM option available to us.

There are also situations in a well planned PM program where economics and/or technical limitations can dictate a decision to do nothing — he appropriately labeled Run-To-Failure (RTF) option. This RTF option is not to be confused with the more general situation of missing potentially useful PM actions due to oversight or lack of attention to PM planning.

To summarize, there are four basic factors behind the decisions to define and choose preventive maintenance actions:
1. Prevent (or mitigate) failure occurrence.
2. Detect onset of failure.
3. Discover a hidden failure.
4. Do nothing, because of valid limitations.

Source: Anthony M. Smith and Glenn R. Hinchcliffe (Plant Engineering - November 1, 2005)

Develop Good Strategies For Effective Preventive Maintenance (1/2)

Experience has clearly shown that some confusion does exist over just what people mean when they use the term preventive maintenance. One significant factor stems from the evidence that a vast majority of our industrial plants and facilities have been operating for extended periods, years in many cases, in a reactive maintenance mode. That is to say that the maintenance resources have been almost totally committed to responding to unexpected equipment failures. Corrective, not preventive, maintenance is frequently the operational mode of the day, and this tends to blur what is preventive and what is corrective.

In one actual extreme case, a plant developed an entire culture that fostered a feeling of pride in people's ability to fix things rapidly and under pressure when a forced outage occurred. Plant personnel viewed their actions as preventive in the sense that they were able to "prevent" a long outage because of their highly efficient and effective reactive and corrective actions. What the plant staff did not consciously recognize (or acknowledge) was that they were the highest cost per unit producer among their peers.
We use the following definition of preventive maintenance (PM):

Preventive maintenance is the performance of inspection and/or servicing tasks that have been preplanned (i.e., scheduled) for accomplishment at specific points in time to retain the functional capabilities of operating equipment or systems.

The word "preplanned" is the key element in developing a proactive maintenance mode and culture. In fact, this now provides us with a very clear and concise way to define corrective maintenance (CM):

Corrective maintenance is the performance of unplanned (i.e., unexpected) maintenance tasks to restore the functional capabilities of failed or malfunctioning equipment or systems.As viewed by the authors, the entire world of maintenance activity is fully encompassed in these two definitions.

However, there are two troubling factors that people frequently question which give rise to some of the confusions over the "PM or CM" discussions. The first of these involves the games that people play with the terminology. These games can be driven by such diverse nontechnical factors as accounting practices or political (regulatory) pressures. For example, some plants, in addition to planned outages and forced outages, have a third category known as a maintenance outage (MO).

The MO occurs as a result of an unexpected equipment problem which hasn't quite yet reached the full failure state but will do so very soon. So the plant management will delay the shutdown until some off-peak period when the plant outage is more tolerable, and hope that the equipment will hold out until then.

Now from an operational point of view, this is a very smart thing to do — but, as a rule, MOs are not counted when it comes to reporting the plant forced outage rate. Somehow they seem to wind up in the preplanned category ("after all, we planned to fix it next Saturday!"). Make no mistake about it, an MO is a forced outage and should be labeled as such when measurements are made. You are only kidding yourself to do otherwise.

Please also read:
Develop Good Strategies For Effective Preventive Maintenance (2/2)

Source: Anthony M. Smith and Glenn R. Hinchcliffe (Plant Engineering - November 1, 2005)

Sunday, October 25, 2009

SKF Machine Condition Advisor (MCA)

Machine monitoring, made simple.

The SKF Machine Condition Advisor is a rugged, easy-to-use, hand held device that simultaneously measures vibration signals and temperature to indicate machine health and bearing damage - providing early warning of machine problems before a costly breakdown occurs.

Essential plant equipment such as pumps, fans, motors, compressors, gear boxes, cranes and conveyors rely on bearings to keep machines running.

Using the SKF Machine Condition Advisor to measure both the machine condition and bearing activity for changes in vibration and temperature, operations or maintenance staff can detect a pending machine failure before it results in lost production, unplanned downtime and machine damage.

Features
* Quick and easy to set up and use
* Compact, durable and ergonomically designed
* Automatically compares measurements to established standards
* Alert and Danger prompts provide diagnostic confidence
* Efficient, economical and environmentally friendly

Benefits
* Avoid costly failures
* Plan maintenance
* Reduce maintenance costs
* Improve machine reliability
* Ideal for both expert and novice users

Solutions 2.0 Conference Reliability & Operations Solutions supporting Organizational Performance

Featuring:
IMC-2009
24th International Maintenance Conference (more)
OPS-2009 Operations Performance Summit (more)
PdM-2009 Predictive Maintenance Technology Conference (more)
LubricationWorld (more)
Ocean Walk Village Hilton
Daytona Beach Florida, USA
November 17-19, 2009 (Bonus activities on November 16)

Tuesday, October 13, 2009

Four Task Categories To Understand In Undertaking Preventive Maintenance (4/4)


As the name implies, we make a deliberate decision to allow an equipment to operate until it fails — and the maintenance action occurs only after the failure has occurred. There are some limited cases where such a strategy makes common sense:

1. We can find no PM task that will do any good irrespective of how much money we might be able to spend.

2. The potential PM task that is available is too expensive. It is less costly to fix it when it fails, and there is no safety impact at issue in the RTF decision.

3. The equipment failure, should it occur, is too low on the priority list to warrant attention within the allocated PM budget.

4. Note the distinction between FF and RTF. With FF the failure is hidden and we do not want to be surprised by its occurrence if the failure should happen. With RTF, we have made a deliberate decision not to be concerned about failure occurrence, be it evident or hidden, and will simply correct the failure at our time of choosing should it occur.

Four Task Categories To Understand In Undertaking Preventive Maintenance (3/4)


When we do not know how to directly prevent or retard equipment failure-or it is impossible to do so — the next best thing that we can hope to do is to detect its onset and predict the point in time where failure is likely to occur in the future. We do this by measuring some parameter over time where it has been established that the parameter correlates with incipient failure conditions. When such is done, we call it a condition-directed or CD task. Thus, a CD task would pre-warn us to take action to avoid the full failure event. If the warning comes soon enough, our action can most likely be taken at some favorable timing of our choice.

The CD task, like the TD task, has a periodicity for the measurements, but actual preventive actions are not taken until the incipient failure signal is given. The CD task takes two forms: (1) we can measure a performance parameter directly (e.g., temperature, thickness) and correlate its change over time with failure onset; or (2) we can use external or ancillary means to measure equipment status for the same purpose (e.g., oil analysis or vibration monitoring). With the CD task, all such measurements are nonintrusive. The keys to classifying a task as CD are: (1) we can identify a measurable parameter that correlates with failure onset; (2) we can also specify a value of that parameter when action may be taken before full failure occurs; and (3) the task action is nonintrusive with respect to the equipment.

In large complex systems and facilities, there are almost always several equipment items-or possibly a whole subsystem or system-that could experience failure and, in the normal course of operation, no one would know that such failure has occurred. We call this situation a hidden failure. Backup systems, emergency systems, and infrequently used equipment constitute the major source of potential hidden failures. Clearly, hidden failures are an undesirable situation since they may lead to operational surprises and could then possibly initiate an accident scenario via human error responses. For example, an operator may go to activate a backup system or some dormant function only to find that it is not available and, in the pressure of the moment, fail to take the correct follow-up procedure. So, if we can, we find it most beneficial to exercise a prescheduled option to check and see if all is in proper working order. We call such an option a failure-finding task.

Let's look at a simple example-the spare tire in our automobile. If you are like us, you don't really worry about a flat spare tire because you have AAA coverage, and are never more than 10 to 15 minutes away from an ability to get emergency road service-except for that once-a-year trip with the family into "uncharted lands" (e.g., Death Valley). Again, if you are like us, you do check the spare before you leave — and that is a failure-finding task.

Notice that the only intent in such an action is to determine if the spare tire is in working order or not. We are doing nothing to prevent or retard a flat tire (a TD task) or to measure its incipient failure condition (a CD task). It is or is not in working order. And, if it is not in working order, we fix it. That is the essence of what a failure finding task is all about. (Is it OK? If not, fix it.)

Four Task Categories To Understand In Undertaking Preventive Maintenance (2/4)

This is part 2 of the series Four Task Categories To Understand In Undertaking Preventive Maintenance

Time Directed (TD)
In the not too distant past, virtually all preventive maintenance was premised on the basis that equipment could be periodically restored to like-new condition before it was necessary to discard it for a new (or improved) item. This premise thus dictated that equipment overhauls were about the only way to do preventive maintenance.

Today, we are slowly realizing that this is not always the correct path to pursue. However, in many valid situations we still specify PM tasks at predetermined ("hard time") intervals with the objective of directly preventing or retarding a failure. When such is done, we call it a time-directed task. A TD task is still basically an overhaul action-sometimes very complete, extensive, and expensive (like rebuilding an electric motor), and sometimes very simple and cheap (like alignments and oil/filter replacements). As a rule of thumb, whenever we have a planned intrusion into the equipment (even just to inspect it), we have in essence an overhaul-type action which is labelled a TDI (Time-Directed Intrusive) task. Some time-directed tasks can be non-intrusive, such as simple visual inspections or minor adjustments that do not require a breach of the equipment boundary or housing. In this case, the action is simply labelled as a TD task.

More often than not, time-directed tasks tend to be intrusive. A simple example that everyone can picture is the changing of oil in our automobile. Here, we intrude in the PM action by removing the drain plug (which will leak if not properly reinstalled), by injecting fresh oil (which must be of the correct type, grade, and quantity with the fill cap properly replaced), and by replacing the oil filter (which will leak if the gasket is not properly installed). The "hard time" associated with this action is car mileage, which has been suggested by the manufacturer who has collected years of experience defining excessive engine wear as a function of oil deterioration due to contaminants and loss of viscosity.

Notice that this simple PM task, a TDI task, presents several opportunities for human error to creep into the procedure. The keys to categorizing a task as time-directed are:
(1) the task action and its periodicity are preset and will occur without any further input when the preset time occurs;
(2) the action is known to directly provide failure prevention or retardation benefits; and
(3) the task usually requires some form of intrusion into the equipment.

Four Task Categories To Understand In Undertaking Preventive Maintenance (1/4)

By Mac Smith and Glenn HinchcliffePlant Engineering - December 1, 2005

There are four basic factors behind the decision to define and choose preventative maintenance actions:
1. Prevent or mitigate failure occurrence
2. Detect onset of failure
3. Discover a hidden failure
4. No nothing, because of value limitations

By identifying the four factors for doing preventive maintenance, we have also set the stage for defining the four task categories from which a PM action may be specified. These task categories, by one name or another, are universally employed in constructing a PM program, irrespective of the methodology that is used to decide what PM should be done in the program.

The four task categories are as follows:
1. Time-directed (TD): aimed directly at failure prevention or retardation.
2. Condition-directed (CD): aimed at detecting the onset of a failure or failure symptom.
3. Failure-finding (FF): aimed at discovering a hidden failure before an operational demand.
4. Run-to-failure (RTF): a deliberate decision to run to failure because the others are not possible or the economics are less favorable.

Thursday, October 8, 2009

Is Preventive Maintenance Necessary?

Written by William C. Worsham (Senior Consultant and Trainer, Reliability Center, Inc.) Feature article for "Focus on Reliability" Column at MaintenanceResources.com

Reliability Centered Maintenance has changed the way we think about Preventive Maintenance (PM). It has caused some to question whether it is even necessary to do preventive maintenance. The truth is most manufacturing facilities would benefit from a good preventive maintenance program. It would be especially beneficial for those plants that rely on breakdown or run-to-failure maintenance. But, a preventive maintenance program is potentially risky, so it must be administered and performed properly to be successful. This paper will examine both the benefits and risks of preventive maintenance and offer some ideas on how to make it successful. We will start with a definition of preventive maintenance.

What is Preventive Maintenance?

Preventive maintenance is planned maintenance of plant and equipment that is designed to improve equipment life and avoid any unplanned maintenance activity. PM includes painting, lubrication, cleaning, adjusting, and minor component replacement to extend the life of equipment and facilities. Its purpose is to minimize breakdowns and excessive depreciation. Neither equipment nor facilities should be allowed to go to the breaking point. In its simplest form, preventive maintenance can be compared to the service schedule for an automobile.

A bona fide preventive maintenance program should include:
  • Non-destructive testing
  • Periodic inspection
  • Preplanned maintenance activities
  • Maintenance to correct deficiencies found through testing or inspections.

The amount of preventive maintenance needed at a facility varies greatly. It can range from a walk through inspection of facilities and equipment noting deficiencies for later correction up to computers that actually shut down equipment after a certain number of hours or a certain number of units produced, etc.

Many reasons exist for establishing a PM program. Listed below are a few of these. Whenever any of these reasons are present, a PM program is likely needed.

Reasons for Preventive Maintenance
  • Increased Automation
  • Business loss due to production delays
  • Reduction of insurance inventories
  • Production of a higher quality product
  • Just-in-time manufacturing
  • Reduction in equipment redundancies
  • Cell dependencies
  • Minimize energy consumption (5% less)
  • Need for a more organized, planned environment

Why Have a PM Program
  • The most important reason for a PM program is reduced costs as seen in these many ways:
  • Reduced production downtime, resulting in fewer machine breakdowns.
  • Better conservation of assets and increased life expectancy of assets, thereby eliminating premature replacement of machinery and equipment.
  • Reduced overtime costs and more economical use of maintenance workers due to working on a scheduled basis instead of a crash basis to repair breakdowns.
  • Timely, routine repairs circumvent fewer large-scale repairs.
  • Reduced cost of repairs by reducing secondary failures. When parts fail in service, they usually damage other parts.
  • Reduced product rejects, rework, and scrap due to better overall equipment condition.
  • Identification of equipment with excessive maintenance costs, indicating the need for corrective maintenance, operator training, or replacement of obsolete equipment.
  • Improved safety and quality conditions.

If it cannot be shown that a preventive maintenance program will reduce costs, there is probably no good reason other than safety to have a PM program.

The Law of PM Programs:
There are many advantages for having a good preventive maintenance program. The advantages apply to every kind and size of plant. The law of PM programs is that the higher the value of plant assets and equipment per square foot of plant, the greater will be the return on a PM program. For instance, downtime in an automobile plant assembly line at one time cost $10,000 per minute. Relating this to lost production time an automobile manufacturer reported that the establishment of a PM program in their 16 assembly plants reduced downtime from 300 hours per year to 25 hours per year. With results such as this no well-managed plant can afford not to develop a PM program.


Preventive Maintenance Program Risks
As mentioned in the beginning of this report, preventive maintenance does involve risk. The risk here refers to the potential for creating defects of various types while performing the PM task. In other words, human errors committed during the PM task and infant mortality of newly installed components eventually lead to additional failures of the equipment on which the PM was performed. Frequently, these failures occur very soon after the PM is performed. Typically, the following errors or damage occur during PM’s and other types of maintenance outages.
  • Damage to an adjacent equipment during a PM task.
  • Damage to the equipment receiving the PM task to include such things as:
  • Damage during the performance of an inspection, repair, adjustment, or installation of a replacement part.
  • Installing material that is defective, incorrectly installing a replacement part, or incorrectly reassembling material.
  • Reintroducing infant mortality by installing new parts or materials.
  • Damage due to an error in reinstalling equipment into its original location.

Especially disturbing about these types of errors is the fact that they go unnoticed – until they cause an unplanned shutdown. There is some published data that illustrates this point. It comes from the fossil-fuel power industry.

A review of the data from fossil-fueled power plants that examined the frequency and duration of forced outages after a planned or forced maintenance outage reinforces this concept. That data showed that of 3146 maintenance outages, 1772 of them occurred in less than one week after a maintenance outage. Clearly, this is pretty strong evidence that suggests that in 56% of the cases, unplanned maintenance outages were caused by errors committed during a recent maintenance outage.

Having performed and supervised many industrial PM’s, I also support this concept. I can remember many instances where it would take days after a PM was performed to get everything back to normal. This was particularly true when many components that came in contact with the product being produced were replaced. I remember working with the quality people on many occasions to insure that every position on a multiple position machine was once again producing first quality product. Many times it required adjusting and/or replacing components that were adjusted or replaced on the PM.

How to Have a Successful PM Program
The key to a successful Preventive Maintenance (PM) program is scheduling and execution. Scheduling should be automated to the maximum extent possible. Priority should be given to preventive maintenance and a very aggressive program to monitor the schedule and ensure that the work is completed according to schedule should be in place.

Preventive Maintenance Execution:
Traditional preventive maintenance was based on the concept of the bathtub curve. That is, new parts went through three stages, an infant mortality stage, a fairly long run stage, and a wear-out stage. The PM concept was to replace these parts before they entered the wear-out phase. Unfortunately, Reliability Centered Maintenance based on research done by United Airlines and the rest of the aircraft industry showed that very few non-structural components exhibit bathtub curve characteristics. Their research showed that only about 11% of all components exhibit wear-out characteristics, but 72% of components do exhibit infant mortality characteristics. These same characteristics have been shown to apply in Department of Defense systems as well as power plant systems. It is very likely that they apply universally as well. Therefore, they should be taken into account when configuring preventive maintenance on industrial equipment.


In order to have a successful PM program, the message is clear. The PM should focus on cleaning, lubrication, and correcting deficiencies found through testing and inspections. When there is a need to adjust or replace components, it should be done by highly trained and motivated professionals. Predetermined parts replacement should be minimal and done only where statistical evidence clearly indicates wear-out characteristics. In the absence of data to support component replacement, an age exploration program or the collection of data for statistical analysis to determine when to replace components should be initiated. Borrowing from the Japanese, lubrication points should be clearly marked with bright red circles to ensure that lubrication tasks are not missed. Cleaning should be carried our to remove dust, dirt, and grime because these things mask defects that can cause unplanned maintenance outages.

Motivating Preventive Maintenance Workers:
A quality preventive maintenance program requires a highly motivated preventive maintenance crew. To provide proper motivation, the following activities are suggested:

  • Establish inspection and preventive maintenance as a recognized, important part of the overall maintenance program.
  • Assign competent, responsible people to the preventive maintenance program.
  • Follow-up to assure quality performance and to show everyone that management does care.
  • Provide training in precision maintenance practices and training in the right techniques and procedures for preventive maintenance on specific equipment.
  • Set high standards.
  • Publicize reduced costs with improved up-time and revenues, which are the result of effective preventive maintenance.
In addition to explaining the importance of a good preventive maintenance program and the benefits that can be derived from it, training is probably the most effective motivational tool available to the maintenance supervisor. Maintenance and training professionals have estimated that a company should spend $1200 per year for training of supervisors and $1000 per year for each craftsperson. In fact, due to advances in technology, if the company has not provided any training for craftspeople in the past 18 months, their skills have become dated.

Conclusion
It is possible to have a successful preventive maintenance program. From a cost reduction viewpoint it is essential, but it does entail risk. When the proper care is taken, the risks, however, can be minimized. In order to minimize risk, preventive maintenance has to be carefully planned and carried out by well-trained and motivated workers. The biggest benefits of a PM program occur through painting, lubrication, cleaning and adjusting, and minor component replacement to extend the life of equipment and facilities.

Monday, October 5, 2009

Preventive Maintenance: Replacing Incandescent Lamps with LEDS

Currently, there is interest in high efficiency, long-life, light emitting diode (LED) lamps for use in factories, institutional, and commercial applications, because the costs of electricity for lighting and labor for bulb replacement are significant. The goal of the LED manufacturers is to build a very high-brightness white LED that is economical and efficient enough to be used for illumination. To gain widespread acceptance as a legitimate light source for general lighting, LEDs must be able to economically and reliably deliver illumination levels of white light of a quality within today's acceptable standards.

Theory of operation

An LED is a PN junction semiconductor that emits photons when forward biased. The emission of light occurs when minority carriers recombine with carriers of the opposite type in the band gap of the diode. The wavelength of the emitted light — which determines its color — varies according to the semiconductor material.

LEDs are processed in wafer form similar to silicon integrated circuits, and broken out into dice. The simplest packaged LED is the indicator lamp. Typically, LEDs have a mean time between failures (MTBF) of more than 100,000 hr.

Today's ultrabright LEDs exceed the light output of incandescent and halogen lamps. They don't have the maintenance requirements associated with filament lamps. LEDs can be dimmed using a pulse-width modulation (PWM) circuit, which delivers energy in pulses of varying duty cycle.

History of LEDs

The first reports of a device with properties similar to LEDs dates back to 1906 when Henry Round reported electroluminescence while experimenting with carborundum. However, LEDs didn't become commercially available until the early 1960s. Texas Instruments sold an infrared (IR) device for $130 and GE distributed red LEDs through the Allied Radio catalog for $260. They were expensive and sold in low volumes.

IBM used LEDs as on-off indicator lights on circuit boards in a mainframe computer constructed around 1964, which marks the first time LEDs were used to replace incandescent lamps. LEDs used less power, could be mounted directly on the circuit board, and had a much longer life expectancy, which made using LEDs attractive from a maintenance perspective.

In the mid 1980s, the U.S. military began gradually replacing tungsten filament indicators with LEDs, and they began appearing in elevator cars. As with the IBM application, LEDs were designed into pieces of equipment. They were mounted on printed circuit boards (PCBs), mounted in equipment panels and face plates using specific mounting bezels with wires soldered to their leads, and plugged into sockets made specifically for LEDs.

LED performance made a leap in the early 2000s. Companies started manufacturing flashlights using LEDs instead of the traditional incandescent bulb. As improvements were made in brightness and color, LEDs moved farther into tungsten territory. They appeared in traffic signals, home entertainment, and decorative lighting.

Today, LEDs are used in many industries from automotive to architectural lighting applications. Industrial plants are discovering the benefits of replacing traditional bulbs with LED lamps. For example, hundreds of incandescent lamp part numbers now have direct LED-based replacements. Most LED suppliers have extensive cross-reference literature and databases. Standard lamp bases are available, allowing LED lamps to replace incandescent lamps without having to retrofit equipment.

Flashlights continue to get brighter. Some currently available flashlights suitable for industrial use boast as much as 1800 foot-candles (fc) of white light. LED floodlights, work lights, and luminaires for general-purpose lighting applications are available as well.

Benefits

LEDs have enjoyed continued success because they use considerably less power and last much longer than tungsten filament incandescent bulbs. LED lamps use only 10% to 20% of the energy consumed by equivalent incandescent lamps. An average LED life span can exceed 100,000 hr — more than 11 yr.

LEDs are solid-state devices, which make them virtually immune to electrical and mechanical shock — unlike incandescent lamps, which have filaments that are very susceptible to electrical and mechanical shock. Electrical shock comes from constant on-off transitions, transients, and surges; mechanical shock comes from bumping, jarring, and other forms of vibration. Also, LEDs produce very little heat, making them an attractive alternative to incandescent lamps in applications where heat is an issue, such as biotechnology, chemical, and food processing.

Issues

LEDs had to overcome physical and technological issues to get where they are today. The primary hurdles have been drive current, packaging, color, and price. Although these issues have been addressed, they still exist to some degree. Drive current directly affects LED lamp output and lamp life. LEDs are inherently robust. They are capable of delivering high output at high current, as long as heat is extracted properly.

Packaging issues include thermal management, current handling capability, and color. Advanced device packaging allows adequate heat dissipation and increased current capacity. Packaging also affects color, which is extremely important in applications that require white light. Use of LEDs as illumination sources requires white light with a degree of "warmth." This requirement must be met if LEDs are to make any headway in replacing incandescent lamps for general-purpose illumination. Fluorescent lighting addressed this issue. And it appears that LEDs are rising to meet the challenge as well.

The cost-effectiveness of LEDs depends on the application. Today, the system price is high for replacing conventional incandescent lamps with LED-based technology. However, for established LED applications, such as control panel indicators and annunciator lamps, LEDs are more cost effective. Although the unit price is higher, the lower power consumption and longer lamp life help offset the initial purchase price. Some plants can justify the higher cost of LEDs for this application based on lower maintenance costs alone.

Source: Plant Engineering Magazine - January 1, 2005

An Introduction To Maintenance Management Software

Maintenance management software is a complete maintenance solution for businesses and organizations to improve their efficiency. It helps to achieve optimum utilization of vehicles, equipments, and other facilities at the company’s disposal. The functions of a maintenance management software include asset management, inventory ordering, work order generation and management, tracking and reporting, purchasing management, scheduling, service request processing, preventive maintenance, predictive maintenance, and much more.

Maintenance management software is a perfect tool for all types of businesses including manufacturing plants, health care facilities, retail and commercial properties, government firms, and educational institutions. Standard maintenance management software provides effective scheduling of work and generates full history reports. It estimates costs correctly, handles spare parts inventory, improves the reordering system, and enhances the material tracking process. It can keep track of service contracts, problem reports, preventive maintenance schedules, and material inventories. Maintenance management software can reduce paperwork and communication costs. In short, maintenance management software helps to improve the productivity of any business.

Most maintenance management software has facilities for detailed and graphical reports. Most software provides easy report writing tools that do not require any knowledge of programming. Many maintenance management software programs help to automate tracking and scheduling of maintenance activities. Some maintenance software has advanced purpose-built user interface and browser-based requesting system. Built-in procedure libraries are part of most common maintenance management software. A lot of software comes with comprehensive dispatching and scheduling tools that help enhance productivity. Certain software allow you to stay connected with customers, suppliers, technicians, and the back office with a view to achieve best results.

Most maintenance management software are user-friendly and require no training. MPulse, ePAC, Servicom, CrossForm, Smart Maintenance, MainBoss CMMS, FTMaintenance, and FaciliWorks are among the popular maintenance management software available in the market.

Sunday, October 4, 2009

Preventative Maintenance Software

Preventive maintenance software is a program that helps you reduce daily workload and do your department’s job more efficiently. A preventive maintenance software system deals with the various aspects of a maintenance operation such as scheduling employees and work orders, inventory control, purchasing, breakdown maintenance, corrective maintenance and project work. It allows users to recognize and fix possible problems and errors in a system. The preventive maintenance software reduces a company’s workload by managing all the routine operations of the maintenance department.

Preventive maintenance software keeps exact maintenance records for industries that have reliability analysis and validation requirements. It provides information that can be used for cost estimates, cost reduction, budgeting, and cost control. Also, preventive maintenance software identifies high cost areas on procedures and equipments. Standard preventive maintenance management software offers full history records for all maintenance work. It lists and tracks outside customers and vendors and displays information on specific work orders.

Some preventive maintenance software automatically schedule preventive maintenance for up to a year and beyond. Weekend days and holidays can be skipped or included. Equipment tracking is a major function of most preventive maintenance software. The software enters and tracks equipments by name, class, category, and serial number. Preventive maintenance software produces reports on complete equipment preventive maintenance history with detailed information on who did the work and when.

Generally, preventive maintenance software can produce a work order for each piece of preventive maintenance to be done. The work order usually contains step-by-step instructions on how to execute a particular preventative maintenance job. The required machinery and materials are also listed. A full inventory control and tracking is a must for preventive maintenance software. Most maintenance software come with a flexible full inventory control module. When inventory levels run low, the software alerts the operator to reorder.

Source:
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Saturday, October 3, 2009

Preventive and Predictive Maintenance

by Ken Staller, Senior Maintenance Consultant

If you ask ten people what their definition of Preventive Maintenance is, you will get ten different answers. The tasks range from very simple to fairly complex. What's more, the manner in which they are performed and the depths to which they are carried out vary considerably. For the purpose of this guide to Preventive Maintenance (PM) and Predictive Maintenance (PDM), I will use the following definition: PM and PDM are a series of tasks and company policies that, if followed, improve and keep business profits as high as possible. This is achieved by adhering to three general guidelines.

  • Maintain the production equipment and plant utility systems equipment as close to brand new condition as possible and have all equipment ready to start up and run with no unplanned shutdowns.
  • Maintain the production equipment and plant utility systems equipment in the best possible operating condition for the purpose of producing quality manufactured goods while the machines are in service.
  • Complete all PM and PDM work on a regularly scheduled basis without exceeding the "Point of Diminishing Returns on Investment" for the labor, tools and materials required to perform the work.

The difference between Preventive and Predictive Maintenance is that Preventive Maintenance tasks are completed when the machines are shut down and Predictive Maintenance activities are carried out as the machines are running in their normal production modes.

With PM and PDM systems – as in all systems and processes of work – there are the Who, What, When, Where and Why questions to answer before any actual work begins. With the above three guidelines we have already defined the "Why" question.

The "Who" question relates to several different types of members of the PM and PDM team.

  • Someone who has an abundance of maintenance and plant engineering experience should write the individual tasks. To receive the expected results from the investments made in the PM and PDM protocol, the person writing the details of what needs to be done must have a deep understanding of the many aspects of machines. Aging, wear, component material fatigue patterns, effects of dirt and other contaminants, heat/cold, humidity, effects of chemical contact, vibration, lubrication practices, measurement processes, maximum safety methods, work efficiency standards, work scheduling, people skills, and plant processes are all factors that must be carefully considered.
  • The mechanics and electricians that perform the PM and PDM work must be of high caliber and possess the skill levels of a maintenance department. On average, 85% to 90% of PM and PDM work orders call for machine inspection work and only 10% to15% lubrication work. The people performing these tasks must fully understand machine and machine component operations before they can effectively inspect for specific problems and negative operating trends.
  • The management person directly responsible for the people performing the PM and PDM work must understand the work to be accomplished and set the performance standards, goals and expectations. They must be able to monitor the quality and quantity of work completed as well as measure the results. Also, they should be able to make on going changes and improvements to the individual PM tasks as part of an overall continuous improvement effort. These changes are dictated by the results of measurements and changes in the plant processes and equipment. Finally, the management person should also be able to complete component failure analyses. Determining why and how a component failed is the first step in determining how to prevent subsequent failure.
  • The plant upper management must view the PM and PDM work system as required constant work practices that are just as important to the production process as any other function. This will require a minimal planned downtime of equipment to accomplish all PM and PDM work.
  • Production employees also are a significant part of PM systems. They can be, and many times are, the first to see changes in the equipment they operate. Total Productive Maintenance (TPM) represents the active participation of all production employees in various machine set-ups, inspections and, in some cases, the lubrications of machinery. The amount of participation in TPM varies with the complexity of the equipment, the types of processes involved and the overall skill levels of the work force. Training the work force and the setting its expectations varies with the philosophies of the plant management of each facility.
  • Contractors should be included in some PM work, especially the PDM work involved. Many contractors can supply cost effective services in some of the more specialized inspections and tests required. For example, many plants do not have trained refrigeration mechanics and they hire contractors to do the scheduled PM on Heating Ventilation and Air Conditioning (HVAC) units for the plant systems. Other contractor applications may be for air compressor and air dryer PM. In addition, vibration and ultra sonic analyzing is highly specialized aspect of PDM and requires extensive training and high test equipment purchase and upkeep costs.

The "What" and "Where" of PM consists of what equipment is to be inspected and lubricated and to what extent and detail the work is to be performed. Typically detailed PM and PDM procedures are written for all production equipment to insure that all machine components are inspected and lubed for maximum sustained operation. This process should also be applied to other plant equipment systems, such as machines that supply the plant utilities including air compressors, air dryers, boilers, electrical sub-stations, motor control centers, and wastewater treatment. Plant safety systems also should be included, including natural and propane gas systems, tanks, fire alarms and suppression systems, emergency lighting, overhead cranes and hoists, and ceiling mounted items such as lights, fans, and piping. Many plants also choose to include PM work on HVAC systems, overhead door and dock plates, forklifts, company vehicles, truck fleets, roof leak detection, air emissions and other systems usually not considered until there is a problem.

The detail and extent of the PM and PDM work varies with the type of equipment involved. The written PM procedure is the document that tell workers what needs to be done. This document needs to contain all of the tasks that will provide the most thorough inspections and lubrications of machines in planned down time, without exceeding the point of diminishing ROI. Generally, the PM inspections of most machines are one of two types. The first is for any thing that moves or causes some other machine part to move. This needs to be inspected for damage, wear, loose and missing fasteners, etc., and proper lubrications performed. The second is the inspection of static, non-moving machine components such as wiring, plumbing lines and hoses, structural support members, etc., for damage, cracked welds, loose and missing fasteners, etc. These procedures may be lengthy or simple, depending on the type of machines involved. The main concern is that the person writing the procedures is very experienced in plant maintenance and plant engineering. This person must understand and be experienced in all phases of static and dynamic machine principals and actual machine degradation analysis.

"When" PM should be performed depends on several factors. Some machines are simple in design and function and some are not. Typically, there are items to be inspected and lubricated on a daily basis. Other inspections and lubes are progressively more detailed and regularly performed on a bi-weekly, monthly, quarterly, semi-annual and/or annual basis, depending on what is required.

In addition to the machine design and basic function, several other factors help in determining the best time interval between PM tasks. One is the amount of time the machine runs between regularly scheduled shutdowns and/or how much time is available for PM. Does the machine run 24 hours per day, seven days per week, or eight hours per day five days per week? Another factor is the environment in which the machine runs. Is it humid and damp, or extremely hot and dry? Does the machine receive shock loads or run with moderate to high vibration levels? Is the machine subject to chemical spillage or leakage, ultra violet light, etc? Good operating and cleaning practices, or the lack of them, have a significant impact on PM scheduling. In addition, planned shutdowns for plant expansions, machine rebuilds, inventories, vacations, etc., also dictate when some of the more involved PM work can be accomplished.

Predictive Maintenance 101

Most of the above information relates to Preventive Maintenance procedures that are completed on machines while shut down. There are other tasks that are considered Predictive Maintenance (PDM) practices. One of these, usually done while the equipment is shut down, is oil sampling and analysis. Oil samples are taken and sent out to laboratories that specializing in analyzing industrial oils. The cost is relatively inexpensive and provides much valuable information. This process identifies the lubricating ability of the oil; its stability; contents of water, wear metal particles, and dirt; among other aspects.

Another extremely important PDM procedure is vibration analysis. Using a portable vibration analyzer, readings are taken from many points on machines. These readings are direct and extremely accurate measurements of the vibration amounts and frequencies produced by the moving parts of the machine. These vibration amounts and frequencies are used to tell if any parts need replacing or adjustment, and exactly what internal parts are causing problems. Bad bearings, excessively worn gears, and poor coupling alignment can cause excessive vibration, weakened mounting fasteners and many other mechanical problems. Vibration analysis also can tell you if pumps have loose impellers, air cavitation, faulty valves, or mounting problems. In addition, it reveals trending information. When vibration readings are taken, they provide a base number to use as a gauge to determine if and how much internal machine changes are taking place between inspections. This is the very best tool for detecting the correct health of machines and for trending the internal activities inside motors, gearboxes, pumps, large fans, compressors, and many other machine components. There is no better way to detect machine problems before they cause an unplanned shutdown due to a component failure. What's more, the fact that vibration analysis is done while the machines are running in their production modes allows the testing to be done at any time and is especially important for any plant that runs 24 hours per day, seven days per week.

A Comprehensive View of Preventive & Predictive Maintenance

There are many aspects of maintenance and other plant functions that have an effect on the number of machine breakdowns and the length of downtime. Some of these considerations are not normally associated with the term Preventive Maintenance, but nonetheless contribute to equipment failure. Therefore, they should be considered as a part of comprehensive approach to Preventive & Predictive Maintenance.
  • Proper start-up protocols. Start-up operations; changeover and set-up; and shutdown procedures should be carefully planned and consistently implemented on all machines.
  • Procedures lists for unplanned shutdowns. Outline what is to be done when an unplanned power outage occurs and what to do before the power comes back on.
  • Emergency management plans for floods, fire, etc.
  • Machine component rebuild programs to insure quality and consistency.
  • Machine cleaning practices and procedures.
  • Available informational equipment manuals for maintenance personnel.
  • Solid troubleshooting skills by all maintenance personnel
The above information provides an outline of a comprehensive PM and PDM system. This approach is unassuming and leaves little, if nothing, to chance. While there are many variables to take into consideration, if properly designed, instituted and operated, the PM and PDM system will help to ensure dependable and predictable performance from all serviced equipment, machines, and related processes.

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