What is the process of pre-plasticizing?

The pre-plasticizing and metering process is the process of plasticizing polymer materials in the barrel. It is the process of heating, compacting and mixing solid granules or powders to transform from a glassy state to a homogenized viscous fluid state. The so-called "homogenization" It refers to the temperature homogenization, viscosity homogenization, density homogenization and component homogenization of the polymer melt, and the metering procedure is completed at the same time during the plasticizing process. Due to the thermo-mechanical properties of the polymer, it is an important factor affecting the pre-plasticizing process. are the thermal energy input and conversion conditions.



There are three input methods of heat energy sources for the pre-plastic metering process:

1. The barrel is heated from the outside by the electric heating element. The material in the barrel can absorb the external heat supply through heat exchange and heat conduction to soften and melt. temperature gradient.



2. The material is rotated by the screw, and the mechanical energy is converted into heat energy through the shearing mechanism and the friction mechanism, and it heats itself to melt it.



3. The heat energy input method is a combination of 1 and 2. During plasticization, part of the material in the barrel is heated by the outside, and part of the material in the barrel is heated by the rotation of the screw through mechanical heat conversion. The plasticization process and plasticization are controlled by two input methods of heating and function conversion. Quality. The energy balance conditions during pre-molding should satisfy the following formula:

Total heat = convection heat + conduction heat + shear heat + friction heat