relief angle การใช้

IMCO refined the tool's rake and relief angles and reinforced its cutting edges, which afforded users higher metal removal rates and shorter cycle times.
The taps and dies used to cut the thread cannot have efficient rake and relief angles ( because of the square form ), which makes the cutting slow and difficult.
In contrast, most general-purpose endmills have a relief angle such that a plunging cut ( Z-axis-only toolpath ) will leave a very slightly convex surface.
In manual machining especially, the former is useful because its pilot guides the cutter into the correct location ( established by the bolt hole ), and its cutting lips are perpendicular to the hole axis with no relief angle, meaning that a plunging cut, moving in only the Z-axis, will leave a flat surface.