In a finishing line, Ovens are used for two main purposes; for drying the items after cleaning and curing. Ovens are designed in different shapes according to workshop space, size of the item and customer’s needs.
The surface of the items needs to be completely dry before spraying, and so the items go through the drying process in the oven after the cleaning phase. Since the spraying occurs at a high speed, the use of heat factor must be economical and done with great consideration. For getting the ideal result, careful observation and precise analysis of all aspects of the line is of great importance.
When a thermoset powder is exposed to elevated temperature, it will begin to melt. As the material begins to melt, it will flow out and then chemically react to form a higher molecular weight polymer in a network- like structure. This cure process, called crosslinking, requires a certain degree of temperature for a certain length of time in order to reach full cure and establish the full film properties that the material was designed for. The chart below shows a curve of time temperature relationship for a theoretical powder material. The powder would cure at any point on the curve from 10 minutes at 420 °F to 25 minutes at 320 °F (10 mins. at 215.6 °C to 25 mins. at 160 °C).
The application of energy to the product to be cured can be accomplished by convection cure ovens or infrared cure ovens