In recent years, glass fiber-reinforced polymer (GFRP) composite materials have become a viable alternative material for different engineering applications due to their superior/excellent properties. The strength of the composite is positively related to the orientation of the fiber material. However, the machinability is still a problem when components are manufactured using the GFRP composites due to their anisotropic properties. The aim of this analytical research paper is to investigate the influence of fiber orientation on the strength and machinability in slot milling of GFRP fabricated using the vacuum infusion method. The fiber orientations of 0°/90° and ±45° are used for the fabrication of GFRP composite laminates. The experiments were conducted using an orthogonal array. Analysis of variance was employed to determine the influence of milling parameters such as cutting speed, transverse feed rate, and axial depth of cut (A.D.O.C.) for the surface finish (R_a), cutting force, and Machinability index (MI). The MI is calculated based on specific cutting pressure. The influence of fiber orientation on the cutting force and surface topography was analyzed. It was concluded that the cutting forces were significantly influenced by the fiber orientation and not affected by the machining parameters. The results revealed that the transverse feed rate was the primary influencing parameter responsible for the increase in MI (40 to 56%). The A.D.O.C. was accountable for the increase in cutting force (55 to 94%). Similarly, the cutting speed influenced R_a, which increased from 17 to 37%.

Glass fibre-reinforced polymer composite materials are widely used in industrial, aerospace and automotive sector. It has excellent properties such as high strength to weight ratio, higher fatigue limit, high stiffness to weight ratio, corrosion resistance and design flexibility. The strength of the composite highly depends upon orientation of the fibre material. Drilling is one of the major machining operations that are carried out on Glass fibre-reinforced polymer composite materials to the need for components assembly. There are many problems encountered while drilling glass fibre-reinforced polymer composites. The major problems are excessive tool wear and delamination of the composite during drilling, which reduce the strength of the composite during application. In the present study, the experimental investigations are carried out to analyse the effect of various machining parameters, i.e. cutting speed and feed rate on the tool wear and delamination. The time and frequency domain analysis of vibration signals measured using sound sensor is also used to predict the effect of machining parameters on delamination as well as to develop the tool replacement strategy.

The research study has focused on the influence of Kevlar fiber surface positions of fibers. The phosphoric acid (PA) pretreated epichlorohydrin (ECH) treatment was used for surface modification of Kevlar fiber. Flexural after indentation (FAI) evaluations were carried out on inter-intraply treated and untreated Kevlar hybrid composites. The surface characterizations of treated and untreated Kevlar samples were investigated by X-ray photoelectron spectroscopy (XPS), XRD, and FESEM analysis. The results revealed that the load-bearing capacity and flexural strength of intraply hybrid composites increased by 45.1% and 36.5%, respectively, compared to interply hybrid composites. Also, the indentation strength of the treated Kevlar intraply hybrid composites was 26.4% higher than that of the untreated intraply hybrid composites. Further, it was analyzed by damage progression and fractography analysis by field emission scanning electron microscopy.