Infrared Application of the Month #1:
Heating Rolls of Clear Protective Laminate
The makers of clear plastic (PET) film for use in protecting the surfaces of electronics devices needed an effective means of controlling film temperature. They initially used oil-filled rollers to try and regulate temperature, but the results were erratic and thus unsatisfactory; inconsistent output meant waste and inefficiency. The applications solutions team at Heraeus Noblelight developed the idea of placing a short wave infrared heating element inside of the roller. Precise temperature control was achieved, and switching of rolls is now a much easier process as well.
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Infrared Application of the Month #2:
Mirror Coating
A mirror manufacturer required process heat for application of the painted-on reflective surfaces of the mirrors. Through experience they found that ceramic heaters had a number of major disadvantages for their application: long heat-up time, large footprint on the production line, and short heater lifetime. They turned to Heraeus Noblelight for a superior solution, and found it in mediumwave infrared heaters. The quick response, long-life lamps provided a much better result, and the targeted properties of IR meant that the process became more efficient as well.
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Tech Center Spotlight:
Shortwave Heaters
Fast and Intensive
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.
Performance advantages include high radiation density in the most compact space; near-instant heating-up and cooling down times; optimized reflection; much more.
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Special Designs:
Ring Heater
Designed for horizontal use, this shortwave ring heater, internally focused for intense rapid heat-up of rods, stakes etc. is made of quartz glass, has a diameter of 8 mm, a two-sided connection, and is available with or without the Heraeus gold reflector.
A wide assortment of ring heaters are in stock at Heraeus. Click HERE to 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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