What type of milling operation creates surfaces perpendicular to the spindle axis?

Face milling is the operation that creates surfaces perpendicular to the spindle axis. In face milling, the cutting tool has teeth on its flat face, which allows it to remove material from the workpiece's surface effectively, producing a flat or contoured surface. This operation is especially beneficial for making flat surfaces, as the cutting action occurs largely on the tool's face rather than on the edges.

The design of the face mill enables it to handle broader cuts, which is effective for creating flat surfaces. Because the spindle rotates vertically, it aligns with the surface being machined, resulting in a perpendicular interaction between the cutting tool and the workpiece. This makes face milling a common choice for various applications where a precise, flat finish is required.

Other milling operations like end milling, slab milling, and angular milling serve different purposes and do not specifically create surfaces perpendicular to the spindle axis. End milling primarily utilizes the cutting edges on the tool's end for angular cuts. Slab milling typically creates flat surfaces but can involve different alignments and is better suited for horizontal machining. Angular milling is used for producing angular surfaces and involves specific tool setups to achieve the desired angle, not necessarily perpendicular to the spindle axis.