• Categories:IR Lamp Technologies & News
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• Time of issue:2024-01-16
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(Summary description)Design and application of infrared radiation heating technology in coating curing

 

Coating curing technology generally uses hot air circulation heating. The air circulation heating have uniform temperature in the furnace and the work adaptability is strong. But the disadvantages are high energy consumption, slow heating for  thick curing workpieces, and the equipment occupies a large area. In order to overcome the shortcomings, infrared radiation heating technology heats the workpieces from the inside to the outside, solving problems such as high energy consumption and slow heating rate.

 



 

Although the infrared radiation heating has the advantages of high heat exchange efficiency, fast response and short drying time and good coating curing quality, it also has shortcomings such as uneven temperature field in the curing box and shadows on workpieces with complex shapes, which ultimately affects the coating and dry quality. In order to overcome the above-mentioned shortcomings caused by simply using infrared drying, a cold air circulation system and a hot exhaust air system are set up in the high-temperature area together with ​​infrared drying. The air volume and wind speed of both are adjustable. When designing, attention should be paid to the exhaust system. The air volume should be slightly larger than the air volume of cold air sent into the system. After production and operation of the equipment, it has been proved that the effect is very good. This is because the cold air sent to the oven drives the hot air circulation in the curing box, which can not only transfer heat evenly to all parts of the complex-shaped workpiece, but also overcomes the inevitable shortcomings of shadows caused by radiation heat transfer. It can also blow away the air film layer adsorbed on the surface of the workpiece, thereby accelerating the external diffusion rate of the workpiece, causing the solvent and water vapor to quickly discharge from the drying chamber, and reducing the relative humidity and solvent concentration in the box.

 





 

The effect of infrared radiation heating technology in paint film curing

 

 

In order to test the design and use effect, after the project installation and debugging was completed, the temperature rise of the entire curing box was tested using a six-point furnace temperature tracker and temperature measurement software. During the heating stage, the heating speed of each part of the workpiece is inconsistent. The closer to the upper part, the faster the heating speed, and the overall heating time is longer.

 

After installing an infrared radiation heater at the inlet, the workpiece heats up faster and the heating time is greatly shortened; the temperature curves of each part of the workpiece have a high degree of overlap, the curve rises steadily during the heating stage, and the curve fluctuates very little during the heat preservation stage. It is not difficult to see that after being heated by the infrared radiation heating system, the temperature curves of various parts of the workpiece almost overlap, indicating that the synchronization of temperature rise on the surface of the workpiece has been greatly improved, the workpiece is heated more evenly, the paint film solidification effect is better, the heating time is greatly shortened, and after heating After this stage, the temperature in the entire curing box remains more stable with very small fluctuations.

 

Conclusion

 

1) In the paint film curing box, the infrared heating system is suitable to be arranged in the entrance heating section. Infrared radiation drying technology is used in the heating stage, and forced convection drying technology is still used in the second half. The combination of the two technologies makes the design more optimized and reasonable.

 

2) The infrared heating components should be reasonably partitioned and grouped according to the design conditions, and the temperature control elements should be scientifically arranged. This is conducive to the temperature control and debugging of radiation drying, making the temperature rise more stable.

 

3) The optimized design of the infrared heating system structure enables three-dimensional adjustment of the relative position to the workpiece in a limited space.

 

4) The infrared heating area is equipped with a forced hot air circulation system, which is beneficial to the uniform heating of the workpiece and improves the curing effect of the paint film.