Infrared Application of the Month #1:
Heating of PVC Flooring before Embossing
A manufacturer of embossed PVC flooring sought a heating system to replace its current one, which was "maxed out" at 100% capacity. The new system -- a fast mediumwave system from Heraeus Noblelight -- increased line speed 40%; product temperature was increased; embossing depth was incresed; and the closed-loop system allowed improved flexibility of power control.
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Infrared Application of the Month #2:
Drying Painted Edges of Performance Ceilings
A manufacturer of high performance ceilings for the worldwide market sought a superior method for drying of the tiles' painted edges. Their current system used a combination of carbon and shortwave, and was efficient, but as the company added a second production line, they wanted to improve efficiency even further. Installation of M110 carbon modules from Heraeus Noblelight provided lower installation cost, enhanced line safety, better paint absorption and shorter reaction time.
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Tech Center Spotlight:
Mediumwave IR Heaters
Stable and efficient, fast response medium wave heaters can transfer high power over long lengths. The high absorption by surface layers and films makes them particularly applicable to thin materials, while the fact that they also have a penetrative effect fits them for use in plastics processing. The heaters can be switched on and off in seconds and are consequently best suited for processes with short cycle times.
Because infrared heaters can be individually matched to a particular application, heating and drying processes can be seamlessly integrated within finishing operations – and with minimum disruption to existing manufacturing lines.
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Special Designs:
Hybrid Carbon/Shortwave Heaters
Heraeus Noblelight's hybrid Carbon/Shortwave heater offers all of the benefits of Carbon and Shortwave heaters using Heraeus' proven twin-tube design. This infrared heater combines a carbon heater and a short wave infrared heater in the proven quartz glass twin tube.
For more on Hybrid Heaters, click HERE.
A wide assortment of other special design heaters is available from Heraeus. Click HERE for details.
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Technical Learning: Workpiece Characteristics and Their Effects, Part 1
In modern industry, infrared equipment is being used to heat a vast range of products, varying in size and complexity. Each different product or material will respond in a different way to infrared heat depending on such factors as mass, surface area, geometrical shape, surface condition, color and conductivity.
Probably the easiest product to heat with infrared is a flat metal sheet with a matt black surface because for a given mass it has a large surface area compared with its thickness. Moreover, it can be placed very close to an infrared panel to receive uniformly the vast majority of the heat available. Its ability to absorb heat is very considerable as a matt black surface has a high emissivity value near to unity, The direction of the projected radiation would be normal to the receiving surface, thus any losses due to the Cosine Law would be eliminated. The simple conditions for rapid and very efficient heating are therefore all easily met. However, in the real world infra- red systems have to be designed to cope with products and situations which can be far more complex than this ideal example, and the aim of this chapter is to give an insight into the behavior of a representative sample of materials and products.
Heating trials with each new product or material remain a prudent step as the results provide a basis for the specification of an efficient and correctly sized oven.
Effect of wavelength
Plastic film An industrial application that illustrates the effect of heater wavelength is the use of infrared to heat shrink-wrap film. In trials two such films of the same thickness, one virtually clear the other aluminum colored were exposed to different heater panels. Aluminum colored film shrank rapidly with all wavelengths, but because of the lack of pigment in the clear film, the long wave heaters took three times longer to achieve the same shrinkage, the medium wave heaters took four times as long while the short wave types were the least effective.
Powder coatings and absorptivity
The curing of coatings on metal substrates has great relevance to the choice of wavelength for corridor ovens. For powder coating with thermosetting epoxy and polyester materials heat transfer does not need to take account of solvent release.
One might expect a fine white powder covering the surface of a metal to have an insulating effect on radiant heat transfer. However, polished metals, exemplified in trials by brass billets, absorb infrared heat very much faster with such a covering than without. This result applies equally before fusion of the powder and at the higher temperatures after fusion.
Long and medium wave infrared unlike short wave are almost blind to color difference.
Metallic powders are an exception to this rule, just as bright metals are more reflective to the longer Wavelengths than to the short. Prior to fusion of the metallic powders, heat absorption occurs at the level of the other coatings. However, a step change in the heating rate occurs at the point of fusion. The eight remaining powders indicate that little if any adjustment would be needed to allow for a change of color or texture in a medium or long wave oven.
Continued in our next issue...
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Contest: Win a FREE iPod!
Keep those entries coming!
Readers of Noblelight News know that infrared technology from Heraeus Noblelight offers innovative, efficient solutions to myriad process heating applications. Infrared heat is suited to many challenges.
Now here's a challenge for our readers. This one is aimed at those currently using infrared heat. Submit a brief (100-200 word) summary of your application, with a brief "before" and after" explanation if applicable, and include a photo (jpeg please). Send it to admin@noblelight.net with the subject line "Contest." The winner will be announced in an upcoming issue. Please note that all entries and photographs become the property of Heraeus Noblelight and may be put to promotional/editorial use at our discretion.
We'll also have a contest for those of you not yet using infrared; look for that one soon.
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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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