Experimental investigations for improving the strength of parts manufactured using FDM process

Abstract

Fused deposition modeling (FDM) is one of the 3D printing techniques that is widely used for the fabrication of prototypes and functional parts. In this technique, parts of any geometry can be built by depositing the fused material in a layer-by-layer fashion until the complete object is created as defined by the CAD model. Strength of the object defines the application domain of the object, and hence it needs to be studied. Process parameters that have a telling influence on the strength of the object are: Layer thickness, build orientation, extrusion temperature, layer height, infill percentage, raster filling, and air gap. This work studies the influence of layer thickness and build orientation on the tensile, flexural, and impact strengths of the object. To achieve this goal, three different materials, viz., bronze polylactic Acid (PLA), wood PLA, and thermoplastic polyurethane (TPU), are chosen. To analyze the results of tensile, flexural, and impact tests, gray relational analysis (GRA) is carried out using L27 orthogonal array. A total of 81 test specimens with varying material, layer thickness, and orientation are prepared using FDM. Results show that the layer thickness and build orientation play a significant role in deciding the tensile, flexural, and impact strengths of the object. Further, optimization is carried out for identifying the best combination of layer thickness and build orientation to achieve best possible tensile, flexural, and impact strengths. MATLAB is used for generating the optimization code.