Inhouse imaging programs pack power into predictive maintenance

In any industry, optimizing production equipment uptime is essential for increasing productivity and competitiveness in the marketplace. How? Secure the reliability of key production assets and prevent failures through predictive maintenance. The key to successful PdM is to monitor equipment for conditions that indicate imminent failure, determine whether remedial action is warranted and then r...

By Jason Wilbur and William Gray December 1, 2005

In any industry, optimizing production equipment uptime is essential for increasing productivity and competitiveness in the marketplace. How? Secure the reliability of key production assets and prevent failures through predictive maintenance.

The key to successful PdM is to monitor equipment for conditions that indicate imminent failure, determine whether remedial action is warranted and then repair the equipment before it fails. The benefit: no unplanned downtime and maximized uptime for exactly the right amount of replacement parts and labor cost.

Typical PdM programs rely on periodic inspections of a plant’s critical assets to determine when a breakdown is “just around the corner.” A critical asset is one that stops production or ruins work-in-process if it fails.

Monitoring and measurement methods range from infrared temperature to vibration, oil analysis, ultrasonic testing and other technologies. Traditionally, trained inhouse personnel follow inspection routes to collect and analyze data from critical equipment.

One frequent exception to the traditional inhouse method has been thermal imaging.

Easier to use

A thermal imager uses infrared technology to take a two-dimensional picture of an object that captures the object’s temperature profile. Unlike IR thermometers that capture temperature only at single points, a thermal imager captures temperatures of both critical components and the entire integrated unit.

Because increases in temperature are associated with nearly all mechanical and electrical failures, thermal imaging has broad application in PdM programs. And best of all, thermal measurement takes very little time (point and shoot) and is done while the equipment is operating.

Until recently, however, thermal imaging or thermography, as it is often called, has been so complex and expensive that only certified specialists have really used the technology. To make thermal imaging part of their PdM programs, facilities needed to contract with outside consultants. That’s starting to change.

Today’s market offers newly affordable, high-performance, easy to use thermal imaging systems for scanning plant equipment. These hand-held devices literally put thermal imaging into the hands of the people most familiar with a plant and its equipment — inhouse maintenance technicians and equipment operators.

While the technology behind these new imagers is as powerful as the instruments used by outside specialists, these newer units simplify the data-collection process. Ergonomically designed into a compact size, they have ample onboard computer strength to perform the required data collection for a PdM program. They also interface with software on a host computer or network, allowing maintenance managers to track temperature measurements and compare thermal images over time.

These new thermal tools add flexibility to PdM that could never have occurred when thermography was performed solely by third-party consultants. Now, maintenance personnel and equipment operators can be trained in thermal imaging, conduct thermography checks on equipment whenever necessary and easily add the technology to existing inspection routes.

Design inhouse routes

Given the capabilities of the latest imaging devices, they’re relatively easy to integrate into existing PdM systems. Maintenance technicians with established skill sets in electrical and electronics technologies, mechanics and other specialties don’t need to significantly change their data-collection procedures. After training in thermography, they need only to add hand-held thermal imagers to their predictive tool kit and thermal measurements to each applicable stop on their inspection routes.

To ensure quick and accurate measurements, the latest hand-held imagers have onboard instructions about how and where to collect images. Inhouse PdM managers can also use the thermal imaging software to plan the routes and images needed at each stop and then download the information into the imager’s memory for use during inspections. Some software also allows PdM managers to edit a route file and add new stops, more refined procedures, updated safety information and the like.

Because using thermal imagers correctly and consistently is essential to a successful thermography program, reminder notes about how to use the instrument are especially important for beginning data collectors to have along. For example, procedures on how to manage the temperature-range readout and span, when to switch from color to black and white and tips on aiming using a laser beam can be included in the latest thermal imagers.

In a PdM program, it is essential to track and compare equipment condition from one thermal reading to the next. That means thermal images must be consistent. From trip-to-trip at a given stop, the technician should stand in the same location and capture the same field in the imager’s sighting window. Instructions to ensure this consistency should be part of the reminder notes. If a skilled employee leaves the company, this feature also preserves the route information for future technicians.

Homegrown thermal imaging

The most obvious benefit of having plant personnel use thermal imagers is an immediate decrease in overhead. Outside specialists are no longer necessary. There are other benefits that maintenance managers can (with some work) quantify monetarily.

For some predictive monitoring tasks, thermal imaging is the best technology available. For example, a savvy maintenance manager could use thermography on small bearings, such as those on conveyors, where vibration analysis is not practical. He or she could use thermal imaging to inspect steam traps or valves that are too high above the plant floor for ultrasound to be effective.

Generally, adding a thermography element to a PdM program produces bottom-line results that are consistent with traditional predictive maintenance. These results include reductions in unplanned down-time due to equipment failure, which can be tied to lost production and probably to lost revenue.

Other factors to consider are the costs in human resources and repair parts. In a PdM environment, maintenance personnel spend less time on reactive (fix-it-when-it-breaks) maintenance. Equipment repair costs, as well as capital equipment costs, decrease when a PdM program extends the lifespan of machine assets. These costs decrease because PdM programs transition maintenance resources away from emergency repairs and into scheduled inspections of key equipment. Inspections simply take less time than repairs. In fact, Federal Energy Management Program studies estimate that a properly functioning PdM program can provide a savings of 30% to 40% over a reactive maintenance approach.

Facilities that bring thermography inhouse can not only inspect equipment more frequently than annually outsourcing inspections, they can also inspect after a repair is made to verify its success. And, by controlling the actual measuring process, internal knowledge of equipment operations also increases.

Finally, the consistency and reporting capabilities afforded by portable imagers and their associated software is significant. Not only does the route-creating capability of software pay off in consistent imaging, but its reporting capability also allows imaging information to get into the hands of the appropriate parties with greater efficiency.

Make training effective

Training on the use of the portable thermal imagers is essential to a successful PdM program. Both supervisors and the technicians who perform inspections need training.

Effective training shortens the learning curve for technicians and helps ensure that they collect useful images from the beginning of a program. Typical training includes information on thermal imaging techniques, electrical and mechanical applications and guidelines for implementing PdM programs.

The most important lesson a technician can learn is to constantly refer to the route information in the imager and follow the instructions. Unread safety information does not stop accidents.

In today’s competitive global marketplace, the bar for operational excellence continues to rise. In order to compete more effectively, manufacturers must cultivate the ability to predict demand and eliminate challenges to productivity. Thermal imaging is one of many high-impact, predictive technologies, but it is a technology that is an indispensable part of a complete predictive maintenance strategy for optimizing critical production assets.

The Bottom Line…

  • Thermal imaging has become a trusted maintenance tool, and is emerging as an in-house technology

  • Plan your thermal imaging route carefully to maximize effective data collection.

  • Federal estimates show that an effective PdM program can save 30% to 40% over reactive maintenance.

  • Supervisors and technicians need effective training with thermal imaging equipment.

  • Jason Wilbur is with Raytek: A Fluke Co. in Everett, WA, and can be reached at . William Gray, CMRP, a maintenance reliability specialist in Rhinelander, WI, can be reached at (715) 369-4484. Article edited by Jack Smith, Senior Editor, PLANT ENGINEERING magazine, (630) 288-8783, .

    • Fig. 1. Maintenance technicians and equipment operators are the people most familiar with a plant and its equipment. They are also the people who benefit directly from today’s high-performance, easy-to-use thermal imaging systems for scanning this equipment. These handheld thermal-imaging instruments literally put the power of predictive maintenance into their hands.

      Fig 2. Consistency is extremely important when designing an effective predictive maintenance program. For example, each time a technician performs an inspection; he or she should stand in the same location and capture the same field in the sighting window of the thermal imager. Reminder notes can be stored within the latest thermal imaging instruments to ensure inspection instructions are followed consistently.

      Make safety a hallmark of your IR program

      To keep your thermography inspections accurate , effective and safe, establish written inspection procedures for measurement collection and interpretation

      The safety of personnel working with or in the proximity of energized electrical equipment requires the use of proper personal protective equipment

      In the United States, refer to NFPA-70E (considered a relevant and reasonable standard by OSHA) for guidance on proper safety precautions and appropriate personal protective equipment

      Outside of the United States , consult the relevant international, federal and local government requirements for electrical safety.

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