Study on the Influence of Printhead Intake Velocity on Pressure of Sand Mold 3D Printer

To achieve the precise forming of sand mold for 3D printing, the relationship between the printhead intake and the pressure fluctuation in the printhead during startup and printing of sand mold 3D printer was studied, and the relationship between the two and the causes of pressure fluctuation is analyzed. With the help of computational fluid dynamics and Fluent software, the internal flow model at a single nozzle is established, and the ink flow under 10 groups of different inlet velocities is simulated to obtain the flow contour and pressure fluctuation values. Combined with the small-channel gas-liquid flow pattern, the relationship among the air intake velocity and the pressure fluctuation and the reasons for the pressure fluctuation are analyzed. The results show that with the increase of intake velocities, the pressure fluctuation amplitude increases. In addition, the disturbance degree of gas-liquid interface wave leads to the difference of pressure fluctuation amplitude as the gas-liquid flow pattern changing. The simulation results agree with the experiments. Therefore, according to the relationship between the intake velocity and the pressure fluctuation amplitude, the stability of the printing system can be improved by limiting the speed ratio of supply pump and return pump. (paper)