Drilling performance of flax fibre epoxy composites: Induced thrust force and delamination damage analyses

Drilling of fibre reinforced composites is challenging because it causes severe damage that can deteriorate the mechanical performance of the composites. In this experimental study, flax natural fibre reinforced epoxy composites were used as samples for assessment of drilling parameters on drilling thrust force and delamination damage. Drill diameter, spindle speed and feed rate were the drilling parameters used for analyses of delamination damage and thrust force. Taguchi method of L18 orthogonal array was implemented as the experimental design layout. The elucidation of delamination damage was carried out using delamination factor whereas the acquisition of thrust forces were completed using a Kistler force dynamometer. Results showed that the tool diameter had the greatest influence on the thrust force. It is suggested that lower feed rate should be able to minimise the peel up delamination at the entrance and push out delamination at the exit surface of the composites. Thereupon, larger feed rate resulted in the excessive thrust force that induced higher delamination damage on flax fibre composites. (C) 2020 The Authors. Published by Elsevier Ltd.