FDM Process Parameter Optimization by Taguchi Technique for Augmenting the Mechanical Properties of Nylon–Aramid Composite Used as Filament Material

Fused deposition modelling (FDM) is one such technique of additive manufacturing (AM) that deposits the extruded thermoplastic material layer by layer to build the desired part. The study is focused on the introduction of new thermoplastic material that widens the application of FDM process and also to use the part for functional purpose rather than just the prototype. Nylon is used as the feed filament material for FDM due to its higher mechanical properties and wear resistant characteristics that are often used as sliding bearing. The properties of nylon are further enhanced by adding the aramid short fibres. In this investigation, the process parameter optimization of FDM process is performed by using Gray Taguchi technique for the quality and mechanical characteristics enhancement. Layer thickness, print temperature, raster angle, infill part density and infill pattern style were considered as the influencing factors for optimization. Mechanical properties including tensile strength, flexural strength, impact strength and compression strength (responses) were studied for the designed experiments which were conducted according to ASTM standards. Analysis of variance was performed using Minitab 18 software to understand the signal-to-noise ratio for the respective objective. The overall combined objective is framed by providing equal importance to all the four responses. From the analysis, the following factors were identified as the optimum settings, layer thickness of 0.4 mm, print temperature of 300 °C, infill part density of 90%, raster angle of 90° and infill pattern style of rectilinear. The results from the test sample printed at the determined optimum setting has exhibited tensile strength of 51.455 MPa, flexural strength as 98.164 MPa impact strength of 0.637 MJ/sq m, compressive strength as 19.42 MPa. The test result of the parts printed from pure nylon as per the prescribed standard setting exhibited tensile strength of 48 MPa, flexural strength as 80.5 MPa, impact strength as 0.51 MJ/sq m and compression strength as 18.12 MPa. A significant increase by 7.2% in tensile strength, 22.7% in flexural strength, 27.4% in impact strength and 7.5% in compressive strength were noticed. From the investigation, it was possible to conclude that even short fibre composites can also be used as FDM raw materials and valid predictions can be made using regression equations with very less error and is justified by experimental trails. © 2019, The Institution of Engineers (India).