Abrasive flow machining (AFM), also known as extrude honing, is a
method of smoothing and polishing internal surfaces and producing
A one-way or two-way flow of an abrasive media is extruded through a
work piece, smoothing and finishing rough surfaces. One-way systems
flow the media through the work piece, then it exits from the part.
In two-way flow, two vertically opposed cylinders flow the abrasive
media back and forth.
The process was first patented by the Extrude Hone Corporation in
The process is particularly useful for difficult to reach internal
passages, bends, cavities, and edges. Particular advantages are the
directional finishes produced, which optimize the flow coefficient
of certain work pieces, and the perfectly formed, tangentially
blended radii formed on edges, which improves high and low cycle
fatigue strength of certain work pieces.