Parametric Study on the Residual Tensile Strength of Flax Natural Fibre Composites after Drilling Operation

The need for hole making on synthetic and natural fibre composites is inevitable due to further requirement of assembly process of different composite parts. However, regardless of the fibre types, the damage cause by drilling operation, namely delamination and matrix cracking around the hole, often deteriorated the long-term mechanical performance of these composites. In this study, the parametric effects of drilling conditions, namely feed rate, spindle speed and drill point angle on residual tensile strength have been investigated. Taguchi technique with statistical analyses was employed as to analyze the residual tensile strength of woven flax epoxy composite after drilling process. A three-axis CNC machine was used to create a hole on the composite specimens based on two levels of drilling parameters and drill bit geometries. Subsequently, static loading tests were performed as specified in the ASTM Standard D3039 (Standard Test Method for Tensile Properties of Polymer Matrix Composite Materials). From the analysis, it is evident that feed rate is the most important parameter that influence the aforementioned output.