Influence of extrusion methods on discharging controllability of 3D printing with viscoelastic slurry

In the application of ceramic 3D printing technology based on extrusion process, it was found that different extrusion methods have important influence on the controllability of the discharging speed, which leads to obvious difference in the surface quality and the success rate of printing samples. For this problem, two kinds of extruding devices with plunger and screw were selected. Under the basic conditions of Bingham viscoelastic fluid slurry and 0.6 mm nozzle diameter, the 3D printing effect of the two kinds of equipment was compared and analyzed by combining the printing test data and the simulation discharge velocity curve. The results show that the discharging speed of screw extrusion method decreases below 30% than that of the original in 0.03 s, the time required to reach this discharge speed by the plunger extrusion method is 2.4 s. The discharge amount of the plunger extrusion method is 3 times that of the screw extruder method in 0.27 s after the slurry feed is stopped. The flow field analysis shows that the different driving principle of the two extrusion methods under viscoelastic slurry condition is the main reason for this difference.