Heat-transfer process during hot-pressing of flakeboard

Hot-pressing is the key process in flakeboard manufacture. Studies in this field also emphasize the influence on the heat-transfer process of the following factors: temperature of hot-plates, original moisture content (MC), target thickness and target density. In this experiment, dynamic data of temperature changes of the core can be logged through a temperature transducer and computer data log system. The results of the experiment indicates that the core temperature-time curve can be divided into three stages: a stage of a rapidly rising temperature, a stage of moisture vaporizing and a stage of a slowly increasing temperature. If the temperature of the hot-plates or the original MC increases during the first stage, the rate of increasing temperature will accelerate. This rate of acceleration in thin or low density board is very high. During the second stage the time used to vaporize moisture can be shortened by increasing the temperature of the hot-plates or decreasing the original MC. In thin or low density board this time period is short. In the third stage the original MC has no influence on the rate of increasing temperature, while the influence of the other factors is the same as in the first stage. Under different conditions, vaporization temperatures in the mat change.