Quality Magazine

Training Trends: Thermal Imaging Predicts Machine Maintenance

June 1, 2003
By monitoring heat distribution, problems with production machinery can be stopped before they start.

All types of manufacturing and processing depend on the optimal functioning of multiple complex and failure-prone electrome-chanical systems. Equipment failure can result in the unexpected shutting down of critical production lines, increasing costs, necessitating the reallocation of manpower and material, reducing productivity, impacting quality and, if not corrected, threatening profitability.

Fortunately many of those responsible for the maintenance of production and processing systems have embraced preventive maintenance, a concept based on the probability of failure increasing with increased hours of equipment operation. All preventive maintenance programs assume machines will degrade within a statistically ascertainable period of time, the result being either unnecessary repairs or catastrophic failure.

A proactive alternative to preventive maintenance is predictive maintenance (PdM). This method uses direct monitoring of equipment operating condition, efficiency and heat distribution to determine the likelihood of failure or loss of efficiency for all critical systems. A comprehensive PdM program using infrared imaging, which is also known as thermography, and other inspection technologies can mitigate and even prevent costly equipment failures.

A PdM program can help root out potential problems such as dysfunctional pumps, underperforming surface heat exchangers, and even protect automated palletizers from breakdowns that threaten to delay product shipment.

Predictive maintenance programs monitor and record the operating condition of multiple processing, production and packaging lines and supporting equipment so that all maintenance is scheduled on an as-needed basis. According to “An Introduction to Predictive Maintenance,” by R. Keith Mobley, eliminating unscheduled repairs, and scheduled, but unnecessary repairs, means manufacturers and processors can reduce the need for corrective maintenance by as much as 90% over five years. Mobley asserts that a successful PdM program will reduce the life cycle cost and extend the useful life of critical systems by up to 60% and increase manpower utilization by as much as 85%.

PdM programs can help meet the demand for higher production rates without a corresponding increase in maintenance cost and reduced equipment life. According to Mobley, when fully utilized, a PdM program can generate a return on investment well above 100:1 or $100 for every dollar invested.

Unlike run-to-failure or preventive maintenance programs, a successful predictive maintenance program requires comprehensive monitoring of all critical processing systems to determine a baseline operational profile against which suspected operating anomalies can be measured, identified, analyzed and corrected. While the cost of a PdM program is higher than conventional maintenance, these costs can pale compared to a catastrophic manufacturing or processing failure that could have been avoided with PdM.

Heat is often an early indication of damage or malfunction that can lead to failure or safety problems and is a major performance value monitored in a PdM program. Portable, handheld, noncontact thermal imagers scan and permanently record the temperature and infrared thermal image of crucial production and processing equipment.

Data and images are downloaded to a PC, accessed and analyzed by software and are available for comparison with subsequent thermal-imaging scans. The resulting performance profile of key processing components enhances the ability of the PdM program to effectively and accurately predict when necessary maintenance should be scheduled.

Adding thermography to a predictive maintenance program allows the monitoring of thermal efficiency of critical process systems that rely on heat transfer or retention, electrical equipment, and other parameters that will improve both the reliability and efficiency of plant systems.

Infrared techniques can be used to detect problems in a variety of plant systems and equipment, including electrical switchgear, gearboxes, electrical substations, transmissions, circuit breaker panels, motors, building envelopes, bearings, steam lines, and process systems that rely on heat retention or transfer.

Thermography can monitor all types of production and processing equipment because of its non-invasive nature. Accurate readings, however, depend on selecting the right thermal imager for optimal maintenance. Thermal imaging system have different performance capabilities and users should understand the trade off between imager functionality and ease of use. For some companies, a thermal imager with nominal functions that requires minimum instruction for maintenance staff may serve its purposes while an ultra sophisticated, difficult-to-use imager may constitute overkill.

Training is a key issue and companies should carefully review user-training programs. Talk with users who have gone through the program. Are they satisfied and do they feel trained and ready not only to effectively operate their imager, but to do so within the rigorous guidelines of a strategically designed and proactively implemented predictive maintenance effort? With adequate, yet minimal training, non-supervisory maintenance personnel can become cost-effective thermographers, fully capable of implementing or expanding a results-oriented PdM program.

Maintenance decision makers considering the purchase of an infrared imager should look for a vendor who can help evaluate their thermal imager and predictive maintenance needs before purchasing an imager. Users need to ask, “What is the time and dollar cost of integrating or expanding thermal imaging into a predictive maintenance program?”

After a purchase is made, the vendor should be able to help develop a strategy for the optimal use of a thermal imager within a PdM program. A successful PdM program is based on a strategy, or blueprint, designed by and for a particular facility to help fulfill specific predictive maintenance objectives. A PdM strategy is the day-to-day script that should be followed, utilizing thermal imaging and all of the predictive maintenance tools available, to achieve positive, verifiable, cost justifiable results sooner rather than later.

Last but not least, a thermal imaging vendor should help develop realistic expectations about what constitutes reasonable payback and successful operation of a thermal imager used to implement a predictive maintenance program.

For some, the commitment to a comprehensive predictive maintenance program will be incremental. Even if a company is not yet ready to make that commitment, the availability of thermal imagers can immediately facilitate valuable processing equipment monitoring, data acquisition and many maintenance efficiencies, more than paying for the cost of the imager. As a good first step, thermal imaging will obtain initial results in the shortest time at the lowest cost while positioning for the future establishment or expansion of a predictive maintenance program.