The temperature of the center layer at the thickest part of the workpiece wall of plastic injection molding is below the heat deformation temperature of the plastic.
The average temperature in the section of plastic injection molded parts, and the time required to cool them to the mold release temperature of specified products;
The central layer temperature of the thickest part of the molded plastic wall, the time it takes to cool below its melting point, or to reach the specified percentage of crystallization.
When solving the formula, the following assumptions are generally made:
The injection of plastic into the injection mold and transfer heat to the injection mold to be cooled;
(2) into the plastic contact closely with cavity inside the cavity, not separation, by cooling contraction between melt and mold wall heat transfer and flow without any resistance, molten material in contact with the mold wall at the same moment its temperature has become.That is, when the plastic is filled into the mold cavity, the surface temperature of the parts is equal to the mold wall temperature.
In the cooling process of plastic injection molding and workpiece, the temperature of injection mold cavity surface is always uniform.
Thermal conductivity of injection moulds surface to a certain extent;(the process of mold filling is regarded as isothermal process, and the material temperature is uniform);
The influences of plastic orientation and thermal stress on the deformation of parts can be ignored, while the size of parts has no influence on the solidification temperature.