Model for the prediction of 3D surface topography and surface roughness in micro-milling Inconel 718

Abstract

Nickel-based superalloy Inconel 718 retains high strength at high temperature, which meets the requirements of micro-parts in the fields of aerospace, energy, and power. However, Inconel 718 is a kind of difficult-to-machine material. During the micro-milling process, scale effect, multiple regenerative effect, and dynamic response all affect its surface roughness, causing the prediction of surface roughness of micro-milled parts difficult. To solve this problem, we study the predictive modeling of surface roughness of micro-milled Inconel 718. Based on the previously built instantaneous cutting thickness model, cutting force model, and the dynamic characteristics of micro-milling system, the authors establish a flexible deformation model of micro-milling cutter generated by cutting force. Since the machined surface is generated by duplicating the tool profile on the workpiece surface, and based on the actual cutting trajectory as well as flexible deformation of micro-milling cutter, the authors build the surface topography simulation model to predict surface roughness and conduct experiments to verify the accuracy of the model. The research realizes the prediction of surface roughness of micro-milled Inconel 718 parts and partially reveals the machining mechanism of micro-milling.