Effect of Rotational Trapezoid Shaped Nozzle on Material-Distribution in 3D Cementitious Material-Printing-Process (2018-05)¶

3D cementitious material printing process, which is typically used in building and construction area, is getting attractive for both industry and academic. Rotational rectangular nozzle is widely applied in 3D cementitious material printing process to improve surface finishing while maintaining printing speed. However, due to the fact that curved printing path has longer outer side than inner side, material printed by rotational rectangular nozzle in curved printing trajectories becomes unevenly distributed, causing deposited filament to be offset from expected position. In order to ensure uniform material distribution for curved printing trajectories, rotational trapezoid nozzle shape is proposed for 3D cementitious material printing process. In this paper, the material distributions for various trapezoid nozzle were studied by numerical simulations. Validation experiments showed that these simulation results can be used to predict material distribution for curved printing trajectories with trapezoid shaped nozzle. A variable geometry nozzle utilizing the simulation results as controller was then proposed for 3D cementitious material printing process.