Blockage mechanism analysis and optimization design of 3D concrete printhead

Abstract

Fast setting and hardening cement has the advantages of short setting time and high early strength. However, when using screw extrusion for 3D printing, there is often a serious blockage problem, which limits the application. In this study, we presented a novel approach to address this issue. Firstly, the blockage reasons in the printing process were obtained through simulations and experimental tests, then a superhydrophobic coating was applied to reduce the slip coefficient of the screw and the inner surface of the nozzle, the printing performance was improved finally. The results indicated that the pressure gradient in the cylinder decreased by 75.07% compared to the uncoated printhead. The shear rate and the flow velocity at the outlet were homogeneously distributed, and no plug flow was formed in the channel. Even after 60 min of continuous printing, the paste only adhered to the pushing flight flank, and no significant blockage occurred.

Keywords:

• Fast setting and hardening cement
• 3D printing
• blockage
• superhydrophobic coating
• slip

Acknowledgements

The authors also gratefully acknowledge the School of Energy and Power Engineering, Qilu University, Shandong University, and Shenyang Universiyt of Technology, Liaoning University of Technology.

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Additional information

Funding

This work was supported by National Science Fund for Distinguished Young Scholars of China (Grant No.62203198) and Key R & D project of Shandong Province, China (Grant No.2022XGC010701).