Infrared Application of the Month #1:
Embossing Leather
A leather company required process heat for the embossing component of product finishing. Their previous solution was the use of locally-made heaters; these suffered from instability and short lifetime. The manufacturer replaced the heaters with medium wave infrared heaters from Heraeus Noblelight. The resulting process upgrade has yielded longer heater lifetime and overall higher product quality.
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Infrared Application of the Month #2:
Keyboard Manufacture
A manufacturer of a high-tech variety of computer keyboards turned to Heraeus Noblelight for their demanding process. They sought a means of curing the PET keyboards in a manner that would not cause shrinkage nor damage to screen printing. Carbon infrared heaters from Heraeus ensured the high quality standard while reducing cost of manufacturing.
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Tech Center Spotlight:
Shortwave Twintube Heaters
Shortwave IR heaters from Heraeus are suitable for all applications in which the attainment of high temperatures in the shortest possible time is what counts. Their emission maximum is between 0.9 and 1.6 micron. Among their advantages are high radiation density in the most compact space, and low space requirements.
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Special Designs:
Spiral Heaters
With heaters in spiral form discs, tubes or rods made of plastics, metal or glass can be heated homogeneously. Compared with conventional heating methods, spiral heaters can provide savings in energy, time and costs. Heraeus offers a wide range of heaters for special applications.
Click HERE to download a brochure on Heraeus spiral heaters.
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 2 of 3
Technical Learning Q&A: A Comparison of Convection vs. Infrared, Part 2 of 3
continued from last month's issue...
Q: Is it possible to cure/dry large conductive components like engine blocks?
A: A slow rate of heat transfer from air allows heat to conduct into components leading to long heat up times. Using infrared emitters with a high transfer of energy enables surfaces to be heated more rapidly overcoming conduction losses.
Q: What about the noise?
A: Large convection ovens generate a lot of noise from fans and air movement or turbulence. This causes health and safety implications. Infrared ovens with low air movement cause less noise.
Q: Can you heat in vacuum?
A: With convection it is not possible. Infrared emitters can be used to heat components in a vacuum chamber.
Q: What happens in a "dirty" environment?
A: Combustion products, recirculation of dust etc. make convection unsuitable for "clean" applications. Infrared heat is clean, no combustion products and no need to recirculate air.
Q: What can you say about adjustable control?
A: Difficult and expensive with convection (more air nozzles) at different air temperature and air speed. It is easy to achieve infinitely adjustable control with infrared emitters by selection of energy densities, wavelengths, and variable power levels.
Q: How well does it heat three-dimensional shapes?
A: Convection has an edge with even heating especially with radical 3 dimensional geometry. Circulated hot air will cause all surfaces reach the same temperature. Infrared has advantage on 2 dimensional parts and heats by line-of-sight. "Hidden areas" will be heated only by conduction through the material. It should be noted that metallic parts conduct heat very rapidly to hidden areas, and a properly designed IR oven uses a "booster" section up front and gives the part soak time to conduct through the part. Even so, process times can be considerably faster with a booster and soak section than with convection alone. Many manufactures now combine both technologies – booster and convection – to get the best of both technologies.
Q: How about holding part temperature?
A: Convection oven at 200 degrees C air temperature will hold part at temperature without this temperature being exceeded, but limited in maximum air temperature only. Holding with infrared employs electrical controls to prevent temperature increasing or decreasing, generally from a closed loop automatic system.
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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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