This thesis conducted a two-part investigation into the ability of a milling tool cutting insert to resist the impacts that occur during the milling process, with respect to the cutting edge microgeometry. The first part of this thesis contains a mathematical model that was used to predict the cutting forces acting on the tool during milling, accounting for the edge radius. The second part reports the findings of a series of milling tests that were performed, both to verify the mathematical model and to track the wear and failure of the various milling inserts. Five different edge radii were tested and compared. It was found that altering the edge geometry of the tool does affect the cutting forces, wear behaviour, and impact resistance of the cutting inserts, with an edge radius of 35 μm proving to be the optimum choice.