A hybrid modelling approach towards prediction of cutting forces in micro end milling of Ti-6Al-4V titanium alloy

Abstract

Prediction of cutting forces in micro end milling is a key aspect for both quality of machining surface and safety of the tool. Further, estimation of cutting coefficients is very much crucial for precise prediction of actual cutting forces. In general, these are obtained by cutting calibration experiments which consume lot of energy and resources. So, to overcome such impediments and to accomplish a purely analytical modelling, this study proposes a hybrid approach for prediction of cutting forces in micro end milling of titanium alloy Ti-6Al-4V. Preliminarily, cutting force coefficients have been evaluated by using finite element simulation considering orthogonal cutting of Ti-6Al-4V using round edge carbide tool. Johnson-Cook material model has been considered for the flow stress calculation in finite element (FE) analysis. Cutting force coefficients have been extracted by simulating the cutting process for a series of undeformed chip thickness (UCT). Finally, mechanistic cutting force model is developed by integrating the small elemental cutting force by incorporating the extracted cutting force coefficients. An improved UCT algorithm which can be used for both lower and higher value of tool run out efficiently is implemented by considering trochoidal trajectory of tool centre, tool run out, minimum chip thickness and elastic recovery and trajectories of all the preceding teeth for one complete revolution of the tool. To validate the proposed model, cutting force experiments have been carried out and results are compared. A comparative analysis shows a very good agreement between predicted and experimental cutting forces.