Industrial Process Heating
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Infrared Speeds Drying Process for Automotive Parts Finisher Background Industrial Coating Services, headquartered in Indianapolis, Indiana, has been in business since 1983 finishing parts for the automotive and appliance industry. The company has three plants and employs approximately 225 people. On winning the contract to finish engine blocks and heads, the company explored various options for curing and eventually selected a system that uses infrared technology. This has put ICS in a position to use leading edge technology to succeed against heavyweight challenges. Solution BGK Finishing Systems, located in Minneapolis, Minnesota, supplied the infrared oven. It came complete with 23 vertical zones and used 544 emitters for a total connected load of 1545 kW. Each zone can be set up to emit a fixed amount of heat established by the requirements of the part being cured. Characteristics of the part which are considered in establishing a curing setup include recesses, shadows, shape and weight. Oven integrity is maintained since there is no warping or meltdown because of excessive heat. The short wave infrared emitters are equipped with self-cleaning, white ceramic reflectors which are able to withstand temperatures up to 2200°F. Excess powder that lands on the reflector is incinerated and leaves the surface without unduly affecting reflectivity and consequently, the amount of energy getting to the part. Short wave emitters radiate some energy to the ceramic reflectors; and that energy is reflected, absorbed or conducted away. Some of the energy absorbed is re-radiated from the reflector in the form of long wave infrared. Both reflected and re-radiated energy contribute to curing the part in the oven. The infrared oven has significantly fewer components requiring maintenance attention. Essentially the maintenance list includes emitters, reflectors, temperature monitors, exhaust fans and a control system. A gas oven requires more components for proper operation, and therefore generates a more daunting list of maintenance items. Benefits Is infrared a beneficial technology for curing powder coatings on heavy parts? The experiences at Industrial Coating Services (ICS) confirm that the answer is a resounding yes. In August 1994, ICS started operation of a new line installed to finish engine blocks and heads for Navistar International and Ford Motor Company. The technology used for curing black epoxy powder coating was infrared, and the benefits are noteworthy. First, the time for curing a 375 lb. engine block was 6 minutes in the infrared oven, compared to 75 minutes in the gas fired convection oven. Infrared heats through radiation, hence only the outer layer of the part is heated to the requisite cure temperature. In a gas convection oven, the entire block has to be heated to obtain cure. Infrared therefore heats and cures the coating faster, resulting in efficient energy use and increased production. In fact, ICS needs only 5 kWh to cure the powder coating on a 375 lb. engine block. Second, cool down time is faster, which allows the conveyor to be shorter and its drive motor to consume less power. Also, parts can be packaged and shipped more expeditiously. Third, the ICS infrared oven facilitates enhanced controls. Customized control strategies and emitter zoning configurations can be developed for each part. This ensures that curing accords with specifications. The oven can also be allowed to idle on low power during breaks, which further optimizes energy use. Inflexible burner arrangement and high thermal inertia make idling and precise control very difficult in a gas oven. Fourth, the floor space occupied by the ICS infrared oven was significantly less than conventionally expected. The company had tested curing the engine block in a 380 feet long gas convection oven which occupied 7,200 square feet, whereas the infrared oven installed is 47 feet long and occupies 258 square feet. Fifth, there are no on-site combustion emissions associated with the infrared oven. For More Information Contact Mark Gentry at (336) 679-4020 or mgentry@advancedenergy.org.
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