Milling is one of the most productive manufacturing processes for creating high quality surfaces. This process is divided into different types of milling operations, which differ in terms of cutting geometry and process kinematics. For NC-programming, the planner must take all of these into account in order to select the most appropriate type of operation. Most of the restrictions are linked to the topology of the surface and the shape of the overall component. Choosing the right type of finishing is crucial for automated planning of milling operations. This paper presents an approach for this. By considering the local geometry and global accessibility, it determines the technically possible types of finishing operations for any point on a surface. This creates the informational basis for the automated determination of processing types for entire surfaces and components. Conceivable applications are automated process planning (CAPP) or automated NC-programming.