Research On The Fundamentals Of Internal Temperature Distribution And Factors Involved Of Flakeboard During Hot Pressing

Hot pressing is the key of flakeboard production. During the process it determines the final physical and mechanical properties and the production line capability. The mat structure and particle unit is undergoing great changes during hot pressing, coupled with the effects of resin and parameters eventually make the process complicated. Therefore it is very important that research on the heat and mass transfer of flakeboard is favorable to optimize the parameters of hot pressing, and establish the relationship between parameters involved and its final mechanical properties.The methodology of experiment test has been used in this paper. Items involved as follows:(1) Firstly comparing and analyzing the difference between surface and core layer of heat transfer, including the heat transfer rate, temperature gradients of mats with urea formaldehyde and without urea formaldehyde.(2) the effect of moisture content and target density on the heat transfer of flakeboard along thickness direction, including the heat transfer rate, temperature gradient, the vapor pressure gradient between surface and core layers.(3) the relationship between vapor pressure and temperature of surface and core layers, using MATLAB software for the simulation of temperature and vapor pressure curves.(4) the three dimension temperature distribution along mid-plane during hot pressing, the effect of moisture content and target density of mat on the distribution, the flow vapor pressure and the effect on the forming mechanism on density.The innovations of this paper cover the following items:(1) research on the effect of resin on the heat transfer rate, temperature gradient between on the surface and core layers has been carried out. Results show that resin increases the heat transfer and the status of heat conductivity and convection(2) the detecting system of vapor pressure on line has been established, practice show it is reliable and accurate.(3) the developing process of mid-plane temperature distribution of flakeboard during hot-pressing has been detected, which is favorable to understand the mechanism of density forming.(4) Using MATLAB software to simulate the developing process of temperature and vapor pressure during hot-pressing so as to predict thetemperature and vapor pressure.