Controlling Process Factors to Optimize Surface Quality in Drilling of GFRP Composites by Integrating DoE, ANOVA and RSM Techniques

Polymer Matrix Composites are the preferred materials now a days and are used in all the fields of engineering because of its encouraging properties over traditional materials. Glass Fiber Reinforced Polymers (GFRP) is the materials that are used in the manufacturing of household appliances up to aircraft and automobile components. Drilling operation is the common machining operation used to make holes for the fasteners in the mechanical part assembly operations. The surface quality of the hole depends upon the drill machining conditions. The drill hole quality gets degraded because of inefficiency or wear of the drill tools to make holes that are dimensionally accurate and are reliable. The tool wear takes place due to improper machining conditions and wrong working procedures. The tool wear disturbs the structural stability of the composite laminates and virtually, the quality of drilled holes. The poor quality of drilled holes affects the proper assembling of the parts and the operational performance of the final product. The objective of this research work is to control the drill process factors through a systematic approach and to analyze their significance on the quality of machined surface while drilling GFRP composite laminates using High Speed Steel (HSS) twist drills. Optimized numbers of experiments were planned and executed using Design of Experiments (DoE). Full Factorial Design (FFD) of experiments was carried out to collect surface roughness data. A statistical model was established by applying Response Surface Methodology (RSM) technique, to calculate the impact of process parameters on the hole surface quality. The capability of the model is checked using Analysis Of Variance (ANOVA). The outcomes of ANOVA indicated that the most significant factor which influences the surface quality is the drill diameter followed by drill feed rate and drill spindle speed.