Today, every well-known motor car manufacturer has an infrared system installed somewhere. They are still used for bodywork. They are also used in pre-drying, drying of finishing lacquer, as well as in repair drying. Moreover, more and more components are processed with infrared. Petrol tanks, pumps, gears, oil sumps or the brake pads discussed earlier, everywhere there are coatings or protective lacquers which have to be cured or dried. There are also the heating processes for the plastics used in motor vehicles. For example, injection moulded plastic parts can be deburred by heating, a step which improves quality if the plastic part is to be coated or lacquered later.
Infrared heating technology has made great strides since the 1950s. Quartz glass infrared emitters are now used as twin tubes, as that design is more stable and also transfers more power to the surface to be heated. Modern reflectors are no longer external but are now integrated in the emitter itself. A gold coating also reflects particularly well, as around 95% of the infrared radiation reaches the product. This means that the coating is warm more quickly and associated machinery is not heated. An integrated reflector is much less liable to getting dirty.
In the beginnings of infrared heating technology, emitters had relatively low power. Today, if necessary, power densities of up to 1000 kW/m² can be transferred. Such high power is needed for applications such as coil coating. For most applications in the automotive industry, powers of around 100 kW/m² are sufficient. Usually, 20 to 30 kW/m² is sufficient to achieve a fast, economical drying of most coatings.
Modern infrared modules are so compact that they can easily be retrofitted into existing ovens or can complement existing ovens. An example is the infrared booster which can be located in front of a hot air oven for coated plastic bumpers. Pre-drying with infrared speeds up the process.
For complicated components, hot air heating and infrared can be combined to advantage. The infrared emitters provide the direct heat while the heat from the hot air oven seeks out all hidden nooks and angles.
Modern infrared emitters can be perfectly matched to product and process in terms of wavelength, power and emitter shape. In every case it is worthwhile to match the heating source exactly to the process and material, as this ensures that not only is the production speed increased but quality is also improved, reject rates are cut and costs are saved.