Evaluation of delamination damage and surface roughness in end milling flax fibre composites

Flax fibre reinforced composites have been very attractive in numerous applications such as wall and automotive panels. With chemical treatments and modifications, their mechanical competent can be at par with the existing synthetic fibre composites. The flax fibre composites are normally fabricated to near-net shape, but very often these composites require a secondary cutting process such as milling to attain final geometrical and dimensional tolerances. Due to the continuous contact of the milling tool on the composite material during cutting process, several undesirable damage such as delamination, matrix cracking, fibre pull-out; existed which may lead to deterioration of their mechanical strength. In this study, parametric effects of milling parameters, namely; feed rate, spindle speed, and number of end mill flutes on delamination damage and surface roughness, were investigated. Taguchi L18 orthogonal array was used to design the experimental plan. Signal to Noise (S/N) ratio and response tables were implemented to analyse the experimental data. It was found that spindle speed and feed rate had equal effects on delamination damage and surface roughness, whereas the number of end mill flute had a marginal influence on the aforementioned machining outputs.