Mathematical modeling and prediction of the thrust force and torque in drilling of sisal/glass-vinyl ester hybrid composite using the RSM, MLPNN, RBFN and ENN methods

Abstract

Drilling a polymer composite material without defects is not an easy task; even so, these materials are largely used in aerospace and other industries, due to their excellent mechanical properties. Tool wear, delamination and fiber pull out are the major problems in drilling. Literature reveals that the thrust force (<i style="mso-bidi-font-style: normal">th</i>) and torque (<i style="mso-bidi-font-style:normal">tq</i>) have a significant effect on tool life and delamination. Therefore, to improve the performance of drilling, it is essential to study the thrust force and torque. This paper discusses the methodologies used in the prediction and evaluation of the thrust force and torque in the drilling of sisal and glass fiber reinforced vinyl ester resin hybrid composite materials. Experiments are conducted in the CNC machining center, and high speed steel (HSS) drill bits are used in the machining center for the drilling operations. Process parameters such as the drill diameter (<i style="mso-bidi-font-style:normal">d</i>), spindle speed (<i style="mso-bidi-font-style:normal">s</i>) and feed rate (<i style="mso-bidi-font-style: normal">f</i>) are considered as the controlling factors for the study. The experimental data obtained are used for training and testing with RSM and ANN techniques such as MLPNN, RBFN and ENN. The predicted thrust force and torque, based on the MLPNN model, are found to be in very good agreement with the experimental values.