An analytical and numerical modeling method for predicting drilling force and hole expansion of a BTA drill processing Inconel 625 and FeCr alloy laminated materials

This paper aims to predict the drilling force and hole expansion of Boring and Trepanning Association (BTA) drill processing Inconel 625 and FeCr alloy laminated tube sheets, essential in petrochemical and nuclear industries. The paper proposes a combined analytical and numerical modeling approach that integrates discrete forces on multiple cutting edges and guide pads of the BTA drill, experimentally determines the mathematical relationship between the discrete forces, and predicts the drilling force using a calibrated finite element simulation of the cutting edge. Then, a comprehensive evaluation of the drilling forces revealed the torque and feed force distribution for cutting, guide pad burnishing, and friction. Furthermore, a precise finite element simulation model for guide pad burnishing hole wall is developed and combined with the burnishing force identified by the analytical model, enabling hole expansion prediction. The proposed model is validated by drilling experiments on Inconel 625 and FeCr alloy-laminated materials with average prediction errors of 8.4 %, 4.7 %, and 20.5 % for torque, feed force, and hole expansion, respectively, demonstrating the accuracy and industrial applicability of the modeling method.