curing oven types , A curing oven must heat a part repidly to the desired metal temperature,without disturbing the powder on the part ,and exhaust the by-products of cure and combustion.There are three ways to heat parts to the metal temperature required to cure the powder coating , Convection ,which transmits energy by air circulation to heat the part . Radiation,which transmits energy directly to the part without heating the air between the part and the radiation source. Conduction ,which transmits energy to heat the part by coming into contact with the heat source.The physics principles above are more identifiable by the actual ovens that employ them. For example ,conduction heating systems are mostly used to preheat parts for fusion-bonded epoxy applications asuh as those used in pipe and concrete rebar powder coating systems. Because these types of ovens have limited applications in the powder coating undustry
Gas -and electric -fired infrared ovens use radiation in high or low intensities to heat parts. Although IR systems sometimes are used to boost the temperature of the part as it enters a convection oven ,they normally are used to cure powder on parts of simple construction and symmetrical shape. Even though IR systems can efficiently cure powder in a very short time (as little as 30 seconds),they have line -of -sie limitations that prevent them from curing all areas of complex parts. An IR emitter can only provide energy to part surfaces that it sees ,Some heat transfer occurs along the part surface ,however,these is a risk of overbaking exposed surfaces before full cure takes place on hidden surfaces.A sufficient array of IR emitters must be used to cure the entire part.
Convections systems are the most popular type of oven used to cure powder coatings. They are available in drect-fired gas ,indirect-fired gas and electric styles .electric and indirect-fired gas styles are good choices if the by-products of combustion cause discoloration of light-colored powders .Electric can be used when gas is unavaible. The most prevalent oven design in powder coating systmes , direct-fired gas convection ovens circulate the spend combustion air throughout the oven interior to heat a part to the desired metal temerature.