A Study on Edge Milling Operation of NEMA G11 GFRP Composites Based on Grey-Taguchi Method

Milling is one of the most practical machining processes for removing excess material to produce high quality surfaces. However, milling of composite materials is a rather complex task, owing to its heterogeneity and poor surface finish, which includes fibre pullout, matrix delamination, sub-surface damage and matrix polymer interface failure. In this study, an attempt has been made to optimize milling parameters with multiple performance characteristics in the edge milling operation, based on the Grey Relational Analysis coupled with Taguchi method. Taguchi’s L18 orthogonal array was used for the milling experiment. Milling parameters such as milling strategy, spindle speed, feed rate and depth of cut are optimised along with multiple performance characteristics, such as machining forces and delamination. Response table of grey relational grade for four process parameters is used for the analysis to produce the best output; the optimal combination of the parameters. From the response table of the average GRG, it is found that the largest value of the GRG is for down milling, spindle speed of 1000 rpm, feed rate of 150 mm/min and depth of cut 0.4 mm.