What type of broach is categorized as removing material from external surfaces?

The type of broach that is categorized as removing material from external surfaces is the surface broach. This tool is specifically designed for cutting and shaping the outer surfaces of a workpiece. Surface broaches typically have a series of cutting edges that gradually remove material, allowing for precise dimensional control and a smooth finish.

Surface broaching can be employed on a variety of geometries and is particularly effective for achieving flat or contoured external shapes. The design and functionality of surface broaches make them ideal for machining flat surfaces, intricate profiles, and even curves on the exterior of a component, thereby enhancing their utility in various manufacturing applications.

In contrast, internal broaches are intended for removing material from the inside of a hole or cavity, slab broaches are used to machine flat surfaces but more in a thickness sense, and step broaches have multiple steps for creating features or shapes that require changes in diameter along their length. Each of these broaches serves a specific purpose that does not align with the removal of material solely from external surfaces, which highlights the unique role of the surface broach in metal cutting processes.