Approaching Rectangular Extrudate in 3D Printing for Building and Construction by Experimental Iteration of Nozzle Design

In Extrusion based 3D Printing technology, the voids could be reduced and the surface finish of printed parts could be improved with extrudate shape optimization. For large-scale 3D Printing technology like 3D Printing for Building and Construction, reducing printed layer height would increase the fabrication time drastically, while having few effect on voids reduction and surface finish improvement. In this paper, an iterative experimental approach to achieve the optimized nozzle design for rectangular shaped extrudate was proposed. Two nozzle prototypes were manufactured by Fused Deposition Method and implemented for experimental tests, then a new nozzle design was created based on the experimental extrudate shapes. This process iterated until a good rectangular extrudate shape was obtained. Printing tests were conducted with the optimized nozzle, which showed the designed nozzle could help to eliminate the voids among the printed parts and guarantee good surface finish without losing the speed of printing.