Effect of edge trimming on failure stress of carbon fibre polymer composites

Finish edge trimming is often required to bring fibre reinforced polymer composites to final dimensional specifications. However, due to the inhomogeneous nature of these materials, their machining may generate undesirable defects such as delamination and surface roughness. These effects may result in compromising the mechanical strength of the machined component. In this work, an experimental investigation was conducted to determine the effect of cutting parameters on machining quality of multidirectional carbon/epoxy laminates during edge trimming operation. Machining quality was quantified in terms of delamination depth and surface roughness. Delaminations were also characterised by their type and frequency of occurrence. Tensile tests were also conducted on machined samples to determine their failure stress. Correlations were made between delamination depth and failure stress. It was found that machining conditions which promote delamination also result in reducing the failure stress of the machined sample.