The flute of an end mill is the helical or straight groove that runs along the length of the tool, serving two primary functions: providing a cutting edge for material removal and creating a pathway for chip evacuation. Each flute contains a cutting edge along its leading side, while the space within the flute allows chips to escape from the cutting zone.
Flute geometry significantly affects the tool’s performance, influencing factors like cutting efficiency, surface finish, and material compatibility. The flute count determines the balance between chip space and tool strength—fewer flutes provide larger chip clearance, making them suitable for softer materials like aluminum, while higher flute counts improve tool rigidity and surface finish, making them ideal for harder materials like steel.