Abstract

The point geometry of a twist drill is the most significant part which may affect to cutting performance in the drilling process. However, it is really complicated to establish an exact mathematic equation to represent the conical flank surface of a twist drill. In order to simplify the problem and meet the practical engineering demand in the industry, this research focuses on developing an approximate mathematic model of the conical drill point geometry.
Additionally, an integrated CAD/CAM software is developed. This software integrates the modelling function of flute, margin, point and split features and is able to calculate grinding path of each feature. With the help of this software, drill geometric parameters can be modified reasonably according to different requirements easier than ever.
Finally, this research also mentions a CAD/CAM/CAE application to evaluate the cutting performance of a twist drill. The designed 3D model can be imported in Thridwave to predict cutting force, torque and peak temperature during the drilling process. Based on these simulative factors, the cutting performance of a twist drill can be generally evaluated. Four evaluated designs were selected and ground by 5-axis CNC grinding machine. The geometry of the ground drill shows a good agreement with the dimension of each design parameter, which validates the accuracy of the proposed modelling method and the corresponding grinding path.