There is an established history of infrared (IR) in the wood industry, and many of the products manufactured and produced in the furniture, flooring, siding and roofing industries involve IR in one or more of the operations. These operations might include drying and curing of varnishes, lacquers, primers, sealers, paints and finish coats; preheating of wood products for out-gassing; de-hydrating wood veneer in laminating processes, or drying/activating adhesives for laminations. In addition, IR is becoming a prominent player in the MDF industry, for the purpose of preheating prior to the application of low-temp powder coatings, and for the gel and cure of powder on fiberboard.
The reason IR is applied is because of the numerous advantages it has vs. other conventional methods of heat. Because IR heats the product and not the surrounding air, and generally has a faster response, it can be quickly directed to the product/substrate, allowing for shorter time cycles and greater uniformity of heat. Shorter cycles mean less time in the oven, helping to prevent drying or cracking of the wood. Also, the resulting oven footprint is less than convection systems, saving floor space. In most cases, IR penetrates the coating, and solvents are driven out from within, thus helping to reduce blistering problems. IR is a clean form of heat and has minimal air movement involved, thereby reducing the threat of contaminates, and reducing the amount of filtering and filter maintenance. Lastly, IR ovens are adapted to a variety of controls. Controlled IR ovens can easily and accurately provide product temperatures to within extremely close tolerances. Many of the aforementioned advantages will be discussed in greater detail in future articles in this column.