Milling of GFRP composite materials is a rather complex task owing to its heterogeneity and the number of problems, such as surface delamination, which appear during the machining process, associated with the characteristics of the material and the cutting parameters. Optimization of machining parameters is an important step in machining. This paper presents a new approach for optimizing the machining parameters on milling glass-fibre reinforced plastic (GFRP) composites. Optimization of machining parameters was done by an analysis called desirability function analysis (DFA), which is a useful tool for optimizing multi-response problems. In this work, based on Taguchi's L 27 orthogonal array, milling experiments were conducted for GFRP composite plates using solid carbide end mills with different helix angles. The machining parameters such as, spindle speed, feed rate, helix angle and fibre orientation angle are optimized by multi-response considerations namely surface roughness, delamination factor and machining force. A composite desirability value is obtained for the multi-responses using individual desirability values from the desirability function analysis. Based on composite desirability value, the optimum levels of parameters have been identified, and significant contribution of parameters is determined by analysis of variance.

Delamination is a serious issue during drilling of FRP composites. The purpose of this research is to determine the effect of process parameters on delamination during drilling of kenaf and banana fiber reinforced in epoxy hybrid composite using Taguchi method. The FRP composite was fabricated by hand‐layup technique. The fabricated specimen was drilled using HSS drill bits (5, 10, 15 mm) coated with tungsten carbide. The contemplated process parameters are feed, and speed. The “Minitab 18” software was employed to investigate the data collected by taking advantage of the various statistical and graphical tools available. The trials were carried out by taking advantage of Taguchi's L‐9 factorial design orthogonal array. Through several steps, it was found that the optimum drilling parameters are spindle speed = 3000 rpm; feed = 150 mm/min. Thus, in this research, an attempt has been made to optimize the drilling parameters.

Purpose -The purpose of this paper is to develop a mathematical model for the surface delamination through response surface methodology (RSM) and analyse the influences of the entire individual input machining parameters (cutting speed, feed rate and depth of cut) on the responses in milling of carbon fibre reinforced polymer (CFRP) composites with solid carbide end mill cutter coated with polycrystalline diamond. Design/methodology/approach -Three factors, three level face-centered central composite design in RSM was employed to carry out the experimental investigation. The "Design Expert 8.0" software was used for regression and graphical analysis of the data collected. The optimum values of the selected variables were obtained by solving the regression equation and by analyzing the response surface contour plots. Analysis of variance was used to check the validity of the model and for finding the significant parameters. Findings -The developed second-order response surface model is used to calculate the delamination of the machined surfaces at different cutting conditions with the chosen range with 95 per cent confidence intervals. Using such model, one can obtain remarkable savings in time and cost. Originality/value -The effect of machining parameters on surface delamination during milling of CFRP composites using RSM has not been previously analysed.

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Purpose -The purpose of this paper is to develop a mathematical model for surface roughness and delamination through response surface methodology (RSM) and analyse the influences of the entire individual input machining parameters (cutting speed, fibre orientation angle, depth of cut and feed rate) on the responses in milling of glass fibre reinforced plastics (GFRP) composites with solid carbide end mill cutter coated with PCD. Design/methodology/approach -Four factors, five level central composites and a rotatable design matrix in response surface methodology were employed to carry out the experimental investigation. "Design Expert 8.0" software was used for regression and graphical analysis of the data were collected. The optimum values of the selected variables were obtained by solving the regression equation and by analyzing the response surface contour plots. Analysis of variance (ANOVA) was applied to check the validity of the model and for finding the significant parameters. Findings -The developed second order response surface model was used to calculate the surface roughness and delamination of the machined surfaces at different cutting conditions with the chosen range with 95 per cent confidence intervals. Using such a model, remarkable savings in time and cost can be obtained. Originality/value -The effect of fibre orientation during milling of GFRP laminates using RSM has not been previously attempted for analysis.