Dehydration Process Slashes Drying Times

A combination infrared heat and convection automotive paint drying systems has been shown to reduce flash off times by 80% and energy costs by two-thirds.
The Fast Flash Rapid Dehydration Process by PPG Industries was the subject of recent tests conducted at its Application Development Center in Flint, Mich.
The Fast Flash process combines controlled infrared radiation and convection to heat car bodies evenly to remove water or solvents from basecoats before a clear coat is applied. First commercialized in 1999, the process helps to eliminate paint popping and pinholes, which can be caused by improper dehydration.
“This innovative technology can be used in existing automotive assembly plants in the same footprint as current ovens, enabling space-constrained plants to convert from solvent to waterborne basecoats or from solvent to powder clearcoats. In both cases it helps to decrease cycle time and reduce operating costs,” said Don J. Emch, manager, applications and process technology for PPG Industries.
“The Fast Flash process can also be incorporated into new plants and requires less floor space and energy than a conventional flash process.”
Fast Flash technology from PPG can shorten coatings flash-off time to 45 seconds when used in conjunction with the company’s high-solids waterborne basecoats and 90 seconds when using PPG’s powder clearcoat.
Current dehydration time with conventional ovens ranges from 4 to 11 minutes. At 90 seconds, the Fast Flash process also provides the quickest flash-off time for waterborne basecoats applied under powder clearcoats. Compared to a conventional paint oven, operating expenses associated with the Fast Flash process are also lower. Energy costs are reduced by half for the 90-second process and by two-thirds for the 45-second process.
The Fast Flash process comprises two zones that use an oven lined with energy efficient infrared radiation tubes. In the first zone, low power infrared radiation and 100 degrees Fahrenheit low velocity air dehydrate the vehicle body. In the second zone, more intense infrared and 200 degrees Fahrenheit higher velocity air are used to complete the flash-off. Vehicle bodies remain in the oven zones for 45 seconds to 2 minutes, depending on the makeup of the coatings.
When used in conjunction with other innovative PPG technologies, the Fast Flash process can cut the time of the entire automotive painting process in half. According to Emch, by adjusting the infrared tubes and air flow inside the oven, the Fast Flash technology has the ability to dehydrate door jams and other shut-face vehicle surfaces. In addition, the process can match the appearance of horizontal and vertical surfaces produced by a conventional paint oven.