Infrared Ovens - Drying Coatings on Wood
(Additional Video)
It is now common for siding to be factory finished with machine applied coatings. Infratrol has developed a system to force dry these boards and panels using transfer conveyors and high velocity, convected air ovens. The system shown above is designed to process "wood and fiber cement" products with measurements up to a maximum of 48" wide or 24' long or 4" high. A typical system is based upon an average board measuring 6" wide x 16' long and will process approximately 575 average size boards in one hour. Two boards at a time will be transferred to the oven conveyor when lengths are shorter.
The unpainted boards are to be manually fed into the load position and then through your coater using waterbased paint at a nominal thickness of 6 mils wet film. They will then be sped up by a powered roller conveyor to create the gap that will allow the 90° transfer to take place. After transfer onto the oven conveyor, additional flash-off will occur before entering the oven.
The high velocity, convected air, paint drying oven will have multiple zones providing time at a reduced temperature and then additional time at the full drying temperature. This gradual temperature increase will remove much of the water from the coating before the higher temperature "skins over" the paint surface. The critical component in drying the paint is; however, high velocity air impingement. After exiting the oven, the boards will ambient cool on the same conveyor and forced air cooling is usually not required. The system includes all of the conveyors from the coater discharge to the final unloading area and a programmable PLC will control the operation.
Even though Infratrol also builds infrared ovens, we have found that convected air is the best way to remove water from thick coatings, and at a considerable reduction in operating costs compared to infrared heating. If pre-heating of the boards prior to painting is required, infrared ovens may be the best choice. Our laboratory will enable us to test your coatings and products to determine the best possible process.