A flat-end milling cutter, often simply referred to as a flat end mill or square end mill, is a type of milling cutter used in machining operations to create flat-bottomed slots, grooves, and profiles. These cutters are characterized by their cutting edges that are square or flat at the bottom, as opposed to ball end mills, which have a rounded cutting edge.
A ball nose end mill is a type of milling cutter used in machining operations to create contoured surfaces, curved profiles, and 3D shapes on a workpiece. It gets its name from the spherical (ball-like) shape of the cutting end. Ball nose end mills are specifically designed for applications where intricate and curved features need to be milled.