Automotive supplier Cooper Standard in Novi, Michigan, had been considering a standard industrial oven to heat-treat many of the components it produces, but engineers quickly discovered that a custom solution better fits its economic goals.
Rather than using gas- or electric-powered furnaces, the supplier opted for modular, electric infrared heating systems from Intek Corp. for heat treatment.
“Today we use the infrared heating after our injection molding press that makes appliqués for automobile exteriors,” says Jim Anderson, engineering manager at Cooper Standard’s Rockford, Tennessee, plant. “We used to do our batch annealing in a gas oven, but that was a two-hour process.”
Anderson discovered that infrared surpassed gas and electric convection heating in precision, speed, and energy savings. In addition, the economic benefits tip the scales even further toward a custom option.
“We worked with Stricker at Intek to design an oven to meet our product needs, bringing that particular step from hours [using the batch ovens] down to minutes,” Anderson says.
Intek designs and builds custom heating elements, standard and custom industrial ovens, conveyor ovens, and industrial space heaters. Although it can build gas, electric, and/or convection systems, the company specializes in infrared heating elements.
“Because an infrared heater has no moving parts and radiates so effectively, it consumes far less energy than a conventional oven which requires a fan and blower,” says Intek founder Jesse Stricker. “Infrared elements can even be retrofitted to conventional gas and electric ovens for further cost-effectiveness. One customer saved close to $100,000 because instead of replacing their entire gas oven, they chose to install electric infrared heating elements designed to fit their application.”
Switching to infrared ovens can reduce energy and floor space requirements. Gas-fired ovens generally transfer heat by convection, requiring fans or blowers, with energy lost in the process. Additional losses stem from the requirement for heating the entire oven, even for small parts. Electric convection consumes even more energy to produce its heat.
Electric infrared heating elements transfer energy to the substrate of surface area via electromagnetic radiation, so it can operate in a vacuum and never come into contact with a part or material while generating temperatures of about 1,000°F.
“People assume that gas is the cheapest way to heat, but that’s not necessarily the case,” Stricker says. “When considering cost, it is important to include equipment purchase price, floor space required, and energy, installation, and maintenance costs.”
Electrically-heated infrared elements yield as much as 86% of their input as radiant energy that strikes the surface of a product, according to the 2008 edition of the Heating, Ventilating, and Air-Conditioning Systems and Equipment Handbook. Some designs may be as high as 95% in the form of useable heat, with the balance being lost through the power supply lines.
“Duty cycle also factors into efficiency,” Stricker continues. “If you buy a 70kW conventional oven and assume, for example, a 10 cents per kilowatt-hour energy consumption, that comes to $7.00 an hour. But consider how often it is actually firing and consuming energy compared to how long product is inside? An infrared oven might only need to run at 40% duty cycle, so heating cost would drop to $2.80 per hour in this scenario.”
Since the amount of infrared energy varies at each wavelength, manufacturers can adjust the wavelength of electric infrared heaters to match the heat requirements of a given substrate in the oven for optimum performance and control. Infrared heating also offers very fast response times, which is beneficial when holding precise temperature uniformity.
“We are finding that one of the main reasons engineers come to us for an infrared solution is that this technology can be customized to provide exacting control for any particular product,” says Stricker. “Every foot in a conveyor oven path can be zoned for maximum, continuous process heating efficiency, monitored by a thermocouple in each zone.
Electric infrared heater modules – typically in 12" x 24", 12" x 36", or 12" x 48" sizes – become structural members of the oven. They can be designed to work individually for small areas, ganged together for larger areas, or even ceiling hung or wall mounted.
“Because almost every process requires heating or drying at some point, we’re keeping very busy these days,” Stricker says.
Cooper-Standard Automotive Inc.