The current printing of functionally graded materials by using the microflow extrusion often results in a delayed material transition at the exit

leading to the long print times before the materials transition is achieved. In order to improve the mixing efficient and effective of 3D printing slurry

shorten the printing time

make the extrusion be stable and homogeneous of theslurryand ensure the quality of the printing. A response surface model for simulating the experimental strategy was proposed

which combined space filling design and Kriging interpolation algorithms to construct the agent model for screw structure optimization. Five structural parameters

namely screw diameter

screw flight width

screw inner diameter and screw pitch

were selected as design variables

and the maximum area-weighted average shear stress acting on the fluid between the screw surface and the cavity wall were taken as the optimization objective. The optimization of the reducing screw parameters was achieved by using a screening optimization algorithm and a multi-objective genetic algorithm to obtain a set of optimizedthe parameter solutions. Furthermore

the parameterscombination is numericallysimulated and printed the experiment results. The results show that the new structure can effectively improve the mixing efficiency

enhance the mixing effect and increase the change rate of component concentration per unit time.which proves the validity and correctness of the optimization method and is applicable to the process improvement of microfluidic extrusion printing.