Depth of Cut

Depth of cut (also called axial depth or radial depth depending on the operation) is the amount of material removed in a single pass, and selecting the right value is essential for balancing material removal rate, tool life, tool deflection, and surface finish quality. In milling, depth of cut is typically the radial distance from the outer edge of the tool to the machined surface, while in turning operations it is the distance from the outer workpiece diameter toward the center.

Conservative depths of cut preserve expensive cutting tools and maintain excellent surface finish, while aggressive depths remove material faster but demand greater machine rigidity and may result in chatter (vibration) that ruins surface finish and shortens tool life. Machinists choose depths of cut based on the tool geometry (smaller tools take lighter cuts), material being machined (hard materials require lighter cuts), and machine condition (older machines with worn spindles require lighter cuts).

CAM software and cutting tool vendors provide guides for recommended depths of cut for different materials, tools, and machines, helping programmers optimize for each unique machining scenario.