A Study On Internal-mat Conditions During Hot-pressing Process Of Flakeboard

Flakeboards were made of populus tomentosa in this experiment. Temperature transducer, pressure transducer and computer data log system were adopted in this experiment to inspect the dynamic temperature and gas pressure in mat.The results of the experimental study show that 1: during hot-pressing, complex changes happen in mat and temperature, gas pressure changes are the most attractive. Both of them are close and affect each other; 2: the core temperature-time curve can be divided into three stages: the stage of a rapidly increasing temperature, the stage of moisture vaporizing and the stage of a slowly increasing temperature; during the stage of a rapidly increasing temperature, four main factors (MC, the temperature of hot-plates, target density and thickness) affect temperature and gas changes, and gas pressure of core is ascending; during the stage of moisture vaporizing, MC and target thickness affect the time of this stage largely; vapor comes to saturate and gas pressure of core reaches maximum; temperature and press affect each other, so they are in a homeostasis; vaporization temperature is affected by local press and is not 100°C we think usually; gas pressure of core reaches maximum in this stage; during the stage of a slowly increasing temperature, temperature of core increases slowly and gas pressure of core begins to decrease; 3: since thermal conductivities coefficients are less, the capacity of heat preservation is better; the relations of every main factor and thermal properties are close; 4: a mathematics model has been set up to computer the time of hot-pressing of flakeboard and it is proved authentic through validation.