Infrared Application of the Month #1:
Drying Varnish on PVC-coated Polyester Fabric
A manufacturer of tarpaulins sought a means for drying of lacquer onto PVC-coated polyester fabric. The previous method -- a convection oven -- caused occasional overheating and ran at too slow a pace. The new mediumwave infrared system from Heraeus Noblelight upgraded line speed by half, eliminated the overheating issues, and helped create a shiny product, all without modifications to the machine frame.
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Infrared Application of the Month #2:
Automobile Carpet Molding
An infrared heating system from Heraeus Noblelight is helping a manufacturer of molded carpet blanks for automotive use. The versatile system features fifteen individually controllable zones, allowing the production of a wide range of blanks to meet the demands of many different makes and models. The carbon infrared heaters used offer extremely fast response time (under one second).
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Tech Center Spotlight:
Carbon Mediumwave Heaters
High heating efficiency and rapid cool down make the mediumwave carbon heater from Heraeus the only medium-wave heater to offer you shortwave response times. Suitable for all medium-wave applications, this heater also offers the capability to match temperatures to the optimum absorption wavelength for each application. Together, these features eliminate overheating and contamination of sensitive substrates.
A particular large portion of medium wave radiation is absorbed in water, solvents and plastics and converted into heat. This allows significant benefits: carbon heaters dry printing inks, with less stress for the paper because the radiation acts more intensively on the ink. The high power heater increases print drying speed and reduces drying time. It also heats plastics in a targeted manner, with less heating of the surrounding environment.
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Special Designs:
Mediumwave Small Area Heater
For applications requiring precision heating of a specific, small area, Heraeus Noblelight offers the Mediumwave small area heater. Approximate heated area of the example shown here is 2" x 2" and the power output is 400W.
A wide assortment of other special design heaters is available from Heraeus. Click HERE for details.
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Technical Learning Q&A: A Comparison of Convection vs. Infrared
Part 3 of 3
Technical Learning Q&A: A Comparison of Convection vs. Infrared, Part 3 of 3
Part 3 of 3
continued from last month's issue...
Q: How flexible are the technologies in working with mixed batches?
A: Although components heat up at different rates, they never exceed temperature of convection oven. Infrared heats up components at different rates and will reach different temperatures depending on mass. Care should be taken to "group" like parts size and mass.
Q: What about the design of the ovens?
A: For convection ovens, product testing generally is not necessary. Although simple, it results in larger sizes and longer oven times. Infrared ovens normally require advanced product tests to determine oven design (power, wavelength, density, length, zoning, etc).
Q: What can be used for "Class 1 Applications (high solvent)?"
A: Convection ovens are more easily designed for use in Class 1 areas. Again the trade off is simplicity vs. size and efficiency. Infrared systems are more complex to use in Class 1 areas, and like convection will require large amounts of air flow to remove solvents, and interlinks between IR source and conveyor to shut down the system in case of line stoppage. The advantage of IR here is size (reduced footprint) and throughput. A combination of IR and convection may be the best solution.
Q: Which oven type is more common?
A: Convection is widely known and easily accepted. It is easy to use and requires little training. Infrared is a more complex system that offers many more advantages: smaller footprint, less power consumption, zoned heating, closed loop control, quick start up and shut down. Although not as widely used as convection, infrared systems are quickly gaining acceptance as a highly effective alternative to the standard convection technology.
Q: How is power calculated?
A: For convection a simple mass x specific heat x temperature rise calculation provides information for oven design. For IR, tests are often required to determine design.
A: In a 200°C convection oven, the complete component will eventually achieve 200°C. Infrared ovens require more planning than convection for 3 dimensional objects. Because conduction cannot be relied upon to heat hidden areas, care is taken to design oven to equally heat all surfaces. Design and control are key to a good job.
Q: How does color-reflectivity-transmission of material influence oven design?
A: A convection oven will have always the same design and characteristics. Infrared systems are custom designed to suit the substrate being processed.
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That's it for this month's issue of Application Notes for IR Heating. Feel free to encourage your colleagues to subscribe. Just click HERE to send them an invitation to subscribe. It's quick, easy, FREE, and no-obligation.
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