Experimental Evaluation of Rectangular Slot Nozzle on Print Performance in Fused Filament Fabrication Additive Manufacturing Technology Using PLA

The application of Additive Manufacturing (AM) in producing functional parts is growing rapidly. Fused Filament Fabrication (FFF) is a cost-effective and rapidly growing AM technology with an increased focus on minimizing manufacturing time. This work evaluated the feasibility of rectangular slot nozzle geometry of dimensions 6 × 0.6 mm in FFF printer in reducing print time and voids. First, experiments were carried out by varying three process parameters - nozzle temperature, layer height, and print speed to identify stable printing conditions. Next, under stable printing conditions, dimensional accuracy was measured and compared with those printed using a standard circular nozzle. Then mechanical behavior was evaluated using three-point bending test. Finally, a dual-nozzle printing approach was tested, combining the circular and rectangular nozzles to print a single part. The results showed that the rectangular nozzle produced consistent prints within identified process window. The dimensional errors in width and thickness were around 5% for both nozzle types, while printing was 80% faster for the rectangular nozzle when printing ASTM D790 test specimens. These findings demonstrate that rectangular slot nozzle is a viable solution and can be integrated into dual-nozzle printers for faster printing.