Thermal imaging has become an extremely valuable technology in many industries not only as an R&D instrument but also as a test and predictive maintenance tool. Automotive manufacturing is an excellent example of an industry that has an enormously diverse selection of thermal imaging applications. According to Scotiabank’s Global Auto Report 2007, 50 million autos are expected to be sold in 2007. In consideration of the large number of electronic and electromechanical components that are used in the production of each automobile, and the push toward improved reliability, it's understandable that infrared imaging plays such an important role in worldwide production of automobiles.

Thermography has been proven to aid the auto manufacturing industry immensely when used in product R&D, quality assurance, and in the manufacturing process. The use of thermography is not new in automotive manufacturing, but each year there are more and more uses of thermal imaging cameras. In an automobile, many systems and components are temperature dependent.

Infrared imaging is commonly used in the design of mechanical systems. In any car, the proper operation of mechanical systems is critical to safe performance of any vehicle. At the same time, the systems must be produced in the most cost effective manner possible. The brake system is a perfect example. Automotive manufacturers continue to assure that the braking systems are designed to operate properly.

In the design stage of rotors, brake pads and calipers, a high performance thermal imaging system can be used to accurately measure the thermal gradients across the brake pad. The concept is simple: friction causes the wheels to stop. With a high speed thermal imager, design engineers can validate materials and understand the trade-off between material properties and thicknesses with performance.

Infrared imaging is also used in the design of heating/cooling systems. Automobiles have numerous heating and cooling systems, each designed to meet demanding requirements. Thermal imaging is the perfect tool for evaluating the achievement of these requirements. A common example in infrared imaging is the monitoring of the defogging pattern on both the automobile windshield and rear window. In this situation, typically the automobile is placed in an environmental chamber where the ambient temperature can be carefully controlled. Infrared cameras can be used to map the passenger seat heating and cooling mechanisms.

Most new autos have resistive heaters and the thermal camera can provide an excellent map with associated quantitative temperature measurements to assure that passenger comfort and safety are achieved. Monitoring the efficacy of heat exchangers is also a common application for thermal imaging systems. If there are blocked or undersized tubes in a radiator, heater core or other heat exchangers, there will be an insufficient dissipation of heat and the potential for failure. Engine misfire and poor cylinder contribution can also be easily identified with IR analysis.

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Recent improvements in the design of infrared cameras have made it possible to capture high-speed thermal images using a "snapshot" mode of operation. As a result, images can be obtained with an integration time of as low as 1µs.

These infrared cameras are uniquely capable of imaging fast-moving objects and measuring the temperature of any point on the object without the errors associated with motion blur. One relevant application is in the design of automobile tires while running on a dynamometer in excess of 150 mph. Researchers can capture detailed temperature data of tires during dynamic testing that simulated turning and braking loads.

Thermal imaging cameras can be used to non-destructively measure mechanical stresses allowing the analysis of mechanical behavior of many portions of the automotive chassis, even those with complex geometries.

Non-destructive testing of automotive cylinder heads on the production line can be used to visualize the thermal wave produced by an ultrasonic or optical excitation. The propagation of the wave on the surface can be observed by using IR thermography. Infrared imaging can also be used to characterize defects in welds and to identify any voids in materials.

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Infrared cameras have been shown to increase the quality and cost effectiveness of parts being produced for automobile manufacturing. In particular, electronics manufacturers have found that thermal imaging is a very practical solution for printed circuit board (PCB) inspection of thermal anomalies. With high performance infrared cameras, one can identify minute thermal differences (as small as 0.015°C), measure components as small as 5µm, capture thousands of frames per second and events as short as 1µs. In this regard, thermal imaging cameras can be used to verify quality, consistency as well as for failure analysis.

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