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48 POWDER COATING, June 2018 I f you're considering an infrared (IR) oven for your application, then you likely have a few questions about IR technology and how it works. To help get you started, Anne Goyer, IHEA's executive vice president, conducted a one-on-one interview with IRED member Martin (Marty) Powell, Carl- isle Fluid Technologies, Scottsdale, Ariz. Marty has 38 years of experience in the finishing industry, including sales, installation, design, and layout of turnkey finishing systems, spray booths, ovens, pumps, conveyors, and auxiliary equipment associated with these systems. He has been published in several trade journals and speaks at trade shows and various association meetings on code compliance, safety, powder coating, wood finishing, and other finishing equipment. Will IR completely cure powder? I have been told that it only cures what it sees, is that true? Yes, IR provides complete curing. Test- ing should be done to prove out cure times and oven settings for your appli- cation. Many parts, even those with areas hidden from the "sight" of the IR emitter, will cure due to heat transfer throughout the product from the exte- rior to the interior. IR quickly brings parts up to temperature and completes the powder cure in many systems. In addition, by providing zoning from top to bottom of an oven, IR can con- centrate heat where it needs to be ap- plied while not overcuring other areas of the product. In fact, IR is so precise that product temperature can be sensed by the oven controls and temperature can be increased or decreased as needed. Of course, these types of con- trols and zoning will increase the cost of the equipment, but cure times can be reduced from 15 to 20 minutes to just 1 to 5 minutes. is typically makes the added cost worth it. Plus, IR systems greatly reduce floor space over conven- tional ovens, which can be an addi- tional savings for many facilities. How do I decide between gas or electric IR for my application? Which type is most cost- effective to operate, and which works best with powder? Only testing can determine what type of IR you should use for your specific application. The best wavelength de- pends on the emissivity (absorption of heat) of the coating, which will deter- mine the type of IR you should use. In many instances, both gas and elec- tric IR will provide an acceptable cure. If that's the case, then your decision should be based on: • Available energy sources • Capital budget 0 Cost of each type of oven 0 Utilities that must be installed to the oven location • Typical line stoppages during production o Gaps in the line o Response times § Electric IR responds quicker than gas § Line stops and restarts intermittently, so determine what response time your customer(s) can live with Why is IR used as a booster to a convection oven? IR boosters are used to heat up the product surface and increase the pow- der temperature, quickly melting the powder on the parts. Many times, improvements to an exist- ing system can be accomplished by in- stalling a booster oven. It can be as sim- ple as installing a 1- to 3-minute booster oven in front of an existing convection oven. is boost will take the surface of a given part from ambi- ent to anywhere between 300°F to 500°F, depending on what is desired to melt and flow the powder. is boost in temperature will then allow the ex- isting convection oven to complete the cure of the powder. Bottom line, you can increase the line speed of your sys- tem or maintain your line speed with the heavier products by adding a booster oven. Marek W. Urban, Ph.D. Clemson University IR Curing ShopTalk Infrared Equipment Division of IHEA This column is provided to you by members of the Infrared Equipment Division (IRED) of the Industrial Heating Equipment Association (IHEA). The group includes infrared (IR) curing equipment suppliers from throughout North America. We publish the column several times a year to give you the latest infor- mation about IR curing techniques and equipment. Contact information is at the end of the column. Most IR manufacturers offer testing for free or for a fee. Any IRED member can assist you in finding solutions to curing problems and best practices for finishing of coatings. Get the facts about infrared