Infrared Application of the Month:
Drying Screen Printing on Metal
The manufacturer of a wide assortment of metal products for retail use required an efficient method of drying screen printing. Brand logos are applied to many products after painting, and the manufacturer needed a way to dry the screen printing quickly and evenly. A paper substrate is screen printed and then dried while glue is applied.
A mediumwave infrared system from Heraeus Noblelight provided the solution. The drying component of the process is now an in-line, non-stop part of the production. Bottlenecks are eliminated, and a high quality, consistent product is the result.
Click for more examples of IR for industry... [ Back to Top ]
Infrared Application of the Month:
Drying Paint on Machinery Components
A production line producing metal machinery components needed a fast and high-quality means of drying paint on the parts. The manufacturer had been using a hot air oven to dry the paint, but that low-efficiency method suffered extensive heat loss and required a great deal of valuable plant floor space.
Heraeus Noblelight provided a fast response mediumwave infrared drying system that allowed faster preheating, higher throughput, increased quality and a smaller footprint.
Click for more IR heating applications... [ Back to Top ]
Tech Center Spotlight: Wire Protection Screen for IR Windows
Metal mesh is an alternative method for protecting infrared modules. Its primary advantage is mechanical protection of the infrared haters. Wire screen features high open areas for maximum thermal efficiency. Typically it is constructed from welded or woven stainless steel wire with 1.5 - 2.5mm diameter.
Temperature of the wire depends on the infrared energy and airflow, and does not vary significantly among different infrared lamp types. After heat-up, temperature remains fairly stable. Metal mesh is acceptable for many different processes, but the ceramic glass window is a better solution for processes involving thin films and foils.
Read more about Wire Protection Screens... [ Back to Top ]
Special Designs:
InfraDry Modular Infrared System
Dryers for web heating using a clamshell configuration, with one or two side heating are the mark of the Infradry line of web processing equipment. The heating and drying systems typically come complete with closed loop temperature control systems. Depending on the process, Carbon, Medium-wave, or short wave can all be utilized in the Infradry systems for the best match of wavelength and absorption. Line speeds of a 1000+ fpm are possible due to the correct matching of peak wavelength/ absorption and system efficiency.
Learn more about the InfraDry Modular Infrared System from Heraeus Noblelight.
[ Back to Top ]
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° 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.
Continued in next month's newsletter...
View more technical bulletins... [ Back to Top ]
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.
|
