Additive manufacturing is an emerging technique for manufacturing 3-D objects from the design of the component. Lattice structures are incorporated in metal and polymeric materials and find various applications in aerospace, marine, and other engineering fields. The present research work concentrates on incorporating hexagonal-shaped lattice structures through the fused deposition modeling (FDM) technique. The optimization was carried out by varying the printing process parameters such as infill density (80%, 90%, and 100%), layer thickness (0.1 mm, 0.2 mm, and 0.3 mm), and printing temperature (195°C, 205°C, and 215°C). The impact of printing parameters with respect to the quality characteristics responses such as tensile strength/density and dimensional area error can be considered for the optimization process. The samples are prepared using an L9 orthogonal array, and the process condition was optimized using the Taguchi optimization technique. The tensile strength/density is observed to be higher at a lower infill density of about 80%, a minimum layer height of 0.1 mm, and a maximum extrusion temperature of 215°C. From the ANOVA analysis results, the influential parameters sequence for the tensile strength/density was infill density > layer thickness > printing temperature. And the sequence of effective parameters for obtaining the lowest dimensional area error was infill density > printing temperature > layer thickness. Therefore, this research has found the application for incorporating hexagonal-shaped lattice structure in the PLA material. The material is capable of structural applications in automotive and marine applications, etc.

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In the fused deposition modelling technique, various type of thermoplastic is printed layer by layer. Among those biopolymers, Poly Lactic Acid occupies a massive space due to their excellent biodegradability. The present work concentrates on using almond shell particles as potential reinforcement in making Poly Lactic Acid (PLA) filaments by a filament extrusion process using a double screw extruder. The extruded filaments of 1.75 ± 0.5 mm diameter is used to make PLA/almond shell composite. This study distillates the effective process parameters for the 3D printing of PLA/almond shell composite and its compressive strength were evaluated. Design of Experiments is followed for the optimization process. The experiment was conducted by varying the five factors (infill pattern, infill density, printing orientation, printing temperature, and printing speed) and three levels. L27 orthogonal array is developed for the experimental procedure, and Taguchi optimization technique is employed for the optimization process for obtaining maximum compressive strength for the produced PLA/almond shell composite. The experimental results show that the infill density and printing orientation have a higher impact than the other printing process parameters with respect to the compressive properties. The mathematical models are developed from the optimization results for the compressive strength analysis of the PLA/almond shell composites. Based on the regression analysis results, the proposed mathematical model has an error percentage of 3.70% and has a good fit with the experimental results. Fractured samples clearly show that the higher infill density of PLA/almond shell samples doesn’t undergo premature buckling failure under the compressive loading.

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