Process optimisation on the compressive strength property for the 3D printing of PLA/almond shell composite

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.