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

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.

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.

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.

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

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

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