Based on the characteristics of gas compressibility

the concept of compressible gas-assisted extrusion was proposed. To verify the effect of compressible gas on polymer extrusion molding

the two-phase flow model polymer melt phase and compressible gas phase was established by means of finite element method

the non-isothermal viscoelastic numerical simulation of the compressible gas-assisted CG extrusion molding and the traditional without gas-assisted TWG extrusion method were performed. The density distribution of gas-assisted extrusion was not a constant value

but was different with the space distribution of pressure and temperature. Compared with the results of two kinds of extrusion methods

when the interaction of gas on polymer melts and gas compressibility were considered

all physical field distributions of CG extrusion method were obviously different from the TWG method. Shrinkage degree was more prominent when inlet pressure of gas phase increased

which was consistent with the results of experiments. These results and factors could not be reflected in the TWG extrusion simulation method.