Abrasive Flow Machining (AFM) is a precision finishing process that works by pushing a semi-solid, abrasive-laden media through the internal passages of a workpiece under pressure. This media—similar in texture to a firm putty—flows over internal surfaces, removing burrs, smoothing rough areas, and refining edge geometry in areas that are otherwise inaccessible to traditional tools.

Key Steps in the AFM Process:

  1. Fixturing the Part
    The workpiece is clamped in a custom fixture designed to direct media flow precisely through the features that need deburring or polishing.
  2. Media Extrusion
    The abrasive media is extruded through the part by hydraulic cylinders—either in one direction (one-way flow) or alternating directions (two-way flow).
  3. Material Removal
    As the media flows, it gently grinds away surface imperfections, smoothing and radiusing edges in a controlled and uniform way.
  4. Cycle Completion
    The process continues for a preset number of strokes or until a target volume of media has passed through the part, ensuring consistency from part to part.

Customization and Control

AFM is highly customizable to meet different finishing needs. Process parameters that can be adjusted include:

  • Media viscosity (from soft to firm, depending on part material and geometry)
  • Abrasive type and grit (e.g., silicon carbide, aluminum oxide, diamond powder)
  • Flow rate and pressure
  • Cycle time and direction (one-way or two-way flow)

This flexibility makes AFM ideal for finishing complex internal features in aerospace, medical, automotive, and 3D-printed components—where precision, consistency, and repeatability are critical.

Want to Learn More?

See how the Bel Air FM-AFH Abrasive Flow Machine automates this process to deliver burr-free, mirror-smooth internal finishes.