Influence of Conventionally Drilled and Additively Fabricated Hole on Tensile Properties of 3D-Printed ONYX/CGF Composites

The need for fast fabrication of customized composite parts having complex designs and intricate geometries has grown significantly. These products are in prodigious demand in a variety of research and development laboratories as well as industrial and medical sectors. Additive manufacturing (AM) has emerged as a cost-effective solution to the rising demand of complex intricate composite products with reduced production time compared to the conventional approaches. The present paper focuses on the exploration of tensile characteristics of conventionally drilled and 3D-printed hole of ONYX/CGF-based 3D composite dog bone specimens printed by Fused Deposition Modelling (FDM) technique. The 3D printing of dog bone-shaped tensile specimens was carried out using ONYX as the matrix and continuous glass fibre (CGF) as the reinforcement. In the present investigation, important 3D printing experimental parameters such as infill density (30, 40 and 50%), glass fibre orientation (0°, 0°-90° and 0°-45°-90°-135°) and infill geometry (triangular, hexagonal and rectangular pattern) were considered. A total of 18 tensile specimens were 3D printed using Mark Forge 3D printer. Among the 3D-printed specimens, 9 samples were 3D printed with a predefined hole of 4 mm, whereas the other 9 samples were 3D printed without the holes. Later, the samples were conventionally drilled with a 4-mm drill bit. Statistical analysis of the experimental results was also carried out using the L 9 orthogonal array considered for experimentation. The comparative study showed that the tensile strength of conventionally drilled composite exhibited better results than the 3D-printed hole counterpart. The optimal conditions for attaining maximum tensile strength of 3D-printed hole composite of ONYX/CGF were triangular infill geometry, 50% infill density and fibre orientation as 0°. Moreover, the optimal parameters for conventionally drilled composites were observed as rectangular infill geometry, infill density of 50% and 0°-90° fibre orientation.