Numerical modelling of planned corner deposition in 3D concrete printing

Abstract

Analysis of different path planning strategies and the effects of changing printhead direction in the geometrical conformity and the process precision around 90 corner in order to enable a simple and cost-effective way of facilitating the determination of an optimal printing mode for fast and accurate print corners in 3D concrete printing.The material flow is characterized by a viscoplastic Bingham fluid. The printhead moves according to a prescribed speed to print the trajectory. The model solves the Navier-Stokes equations and uses the volume of fluid (VOF) technique. The acceleration steps and jerk (j) carry out the direction change. A smoothing factor is provided to smooth the toolpath. Several simulations were performed by varying the smoothing factor and jerk.Overfilling at the sharp corner was found when the printhead velocity was kept constant while extruding mortar at a fixed extrusion velocity; however, proportional extrusion velocity with the printhead motion has improved the quality of the corner. Otherwise, a slight improvement in the corner shape related to applying a jerk was found.The Computational Fluid Dynamics (CFD) model could take an important amount of computing time to solve the problem; however, it serves as an efficient tool for accelerating different costly and time-consuming path planning processes for 3D concrete printing. Smaller angles and tilted printhead positions should be numerically and experimentally investigated in future research.The developed CFD model is suited for executing parametric studies in parallel to determine the appropriate printing motion strategy for each trajectory with corners.Computational Fluid Dynamics investigation of the path planning strategy for printing trajectory with a right-angle corner in 3D concrete printing.