A Variable-Depth Multi-Layer Five-Axis Trochoidal Milling Method For Machining Deep Freeform 3d Slots

Trochoidal milling is a popular machining method for slotting operation, as it avoids a full tool-workpiece engagement and hence helps, often significantly, slow down the tool wear, which is particularly a concern in the machining of hard-to-cut materials like titanium alloy. However, as the traditional trochoidal milling method assumes a fixed tool orientation, it can only apply to 2D shaped slots, while for many industrial parts the slot to cut is typically a genuine 3D freeform slot such as grooves on a blisk. In this paper, we present a multi-layer fiveaxis trochoidal milling method for machining an arbitrary 3D deep slot that is defined by two freeform side boundary surfaces. Aiming at minimizing the total cutting time, instead of conservatively dividing the slot into equi-depth layers, we strive to minimize the number of layers with variable layer depths while at the same time satisfying the two most critical physical constraints on the tool - the tool deformation and the tool stress. Both computer simulation and physical cutting experiments of the proposed method have been carried out, and the experimental results confirm the feasibility and advantages of the proposed method.