Abrasive flow machining is a finishing process that uses a viscous abrasive media to deburr and polish complex internal surfaces and passages. It can produce a smooth surface finish on difficult to access areas and remove burrs from holes and intersecting passages. The process involves extruding an abrasive media containing abrasive particles mixed in a viscoelastic polymer through fixtures surrounding the workpiece under pressure. This allows the media to flow through holes and passages to abrade away imperfections. Abrasive flow machining is commonly used in the aerospace, automotive, die and mold industries to improve surfaces, reduce wear and extend component life.

1. Abrasive Flow Machining
Tauseef Shaikh
Assistant Professor
Department of Mechanical Engineering
Matoshri Pratishthan’s School Of Engineering
Tauseef Shaikh, Asst. Prof., MPGI SoE Nanded 1

2. Content
1. What is AFM?
2. Need of AFM
3. Abrasive Material
4. Mechanism of AFM
5. Components of AFM
6. Classification
1. One Way
2. Two Way
3. Orbital
7. Process input parameters
8. Application areas
Tauseef Shaikh, Asst. Prof., MPGI SoE
Nanded
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3. Limitations of Conventional Finishing Processes
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Tauseef Shaikh, Asst. Prof., MPGI SoE
Nanded
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4. Abrasive Flow Machining
• It is basically used as a deburring process.
• Developed in 1960 by Extrude Hone Cooperation.
• AFM can be used for;
– Polish and deburr parts internally
– Polish through holes
– Polish intersecting holes
– Calibrate fuel injection nozzles to a specific flow rates
– Difficult to accesses areas
– Remove scratching marks (feed marks) of other processes
– radius
• Uses abrasive grains mixed in a putty (a form of
cement) like matrix which abrades the
surface/burrs from the specific area of the
material.
Tauseef Shaikh, Asst. Prof., MPGI SoE
Nanded
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5. NEED
• Smooth surfaces – Aerospace and precision
components
• High flow rates – Fluid dynamics and nozzles
• Torque and fuel economy – Fuel nozzles and
engine components
• Eliminate the imperfections – Medical field
Tauseef Shaikh, Asst. Prof., MPGI SoE
Nanded
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6. Mechanism Of AFM
1. Initially the material is ploughed by the fine
abrasives which come in contact with the work
material as the rub over the metal surface with high
pressure.
2. The material flow occurs in the direction of the
motion of abrasive particles as well as in lateral
direction, resulting into the formation of the leaps.
3. The further flow of abrasive particles causes
continued work hardening which results in
embattlement and fragmentation of the lips into
micro chips.
Tauseef Shaikh, Asst. Prof., MPGI SoE
Nanded
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7. Mechanism of AFM
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Nanded
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8. Components / Set up of AFM
• Machine
• Abrasive materials/medium
• Tooling
• Workpiece
• Fixture plate
• Fixtures
• Pumping device
Tauseef Shaikh, Asst. Prof., MPGI SoE
Nanded
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9. Machine
• It determines extent of abrasion
• It is Essentially provided with
1. Hydraulic controls
2. Fixtures
3. Volume flow rate device
4. Media advance device
• Its accessories are;
1. Automatic flow timer
2. Cycle timer
3. Displacement system
4. Flow control valve
5. Media heat exchanger
• Standard unit operate between 10 bars to 200 bars and with flow rates of
400 lpm.
Tauseef Shaikh, Asst. Prof., MPGI SoE
Nanded
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10. Classification of AFM
1. One way
2. Two Way
3. Orbital
Tauseef Shaikh, Asst. Prof., MPGI SoE
Nanded
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11. One-way AFM
• One-way flow AFM processing pushes
abrasive media through the work piece in only
one direction, allowing the media to exit
freely from the part.
Tauseef Shaikh, Asst. Prof., MPGI SoE
Nanded
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12. Advantages of One-way AFM
• Faster cycle processing
• Easy clean-up
• Media temperature control generally not
required
• Able to process larger parts
• Simpler tooling and part change-over
• Accurately replicates air or liquids natural flow
• Does not encapsulate work-part in media
Tauseef Shaikh, Asst. Prof., MPGI SoE
Nanded
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13. Two-way AFM
• Most widely used
among the three.
• The typical two-way flow AFM process uses two
vertically opposed cylinders to extrude an
abrasive media back and forth through or around
passages formed by the work piece and tooling.
• Abrasive action occurs wherever the media
enters and passes through the most restrictive
passages
Tauseef Shaikh, Asst. Prof., MPGI SoE
Nanded
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14. Two-way AFM cont…
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Nanded
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15. Two-way AFM(contd.)
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Nanded
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16. Two-way AFM(contd.)
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Nanded
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17. Advantages of Two-way AFM
• Excellent process control
• Can finish both ID and OD of component
• Good control of radius generation
• Fully automated system capabilities
• Faster setup & quick-change tooling
• Faster change-over of media
Tauseef Shaikh, Asst. Prof., MPGI SoE
Nanded
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18. Orbital AFM
• Surface and edge finishing are achieved by
rapid, low-amplitude, oscillations of the work
piece relative to a self-forming elastic plastic
abrasive polishing tool.
• The tool is a pad or layer of abrasive-laden
elastic plastic medium (similar to that used in
two way abrasive flow finishing), but typically
higher in viscosity and more in elastic.
Tauseef Shaikh, Asst. Prof., MPGI SoE
Nanded
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19. Orbital AFM(contd.)
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Nanded
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Before starting of finishing
After starting of finishing

20. Abrasive Media
• It is the mixture of
1. Abrasive particles and
2. Elastic Polymer Elastomers
• Abrasive Particles:-
 Generally used Abrasive particles are Aluminum oxide, silicon
carbide.
 Boron carbides are expensive and suitable for hard materials.
 Silicon carbide has high stock removal rate and is both durable
and economical.
 Diamond abrasive is used for most difficult materials like WC. It
is very effective for removing thermal recast layer.
• Elastic Polymer (Elastomers):-
 Abrasive particles are mixed with this visco-elastomers which
shows change in viscosity under pressure.
Tauseef Shaikh, Asst. Prof., MPGI SoE
Nanded
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21. Tooling
• Tooling consisting of
• Workpiece
• Fixture plate
• Fixtures
• Pumping device
Tauseef Shaikh, Asst. Prof., MPGI SoE
Nanded
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22. Machine Abrasive Workpiece
Extrusion pressure
Flow Volume
Media flow speed
Number of Cycles
Medium viscosity
Abrasive
Concentration
Abrasive
type & size
Restricting
passage flow
and area
Ductile/Brittle
Tauseef Shaikh, Asst. Prof., MPGI SoE
Nanded
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23. AFM process parameters
Abrasive Based
– Abrasive grain size used in AFM varies from 500 grit
(tiny hole) to 8 grit (stock removal and stocking)
– Large abrasives- cut faster
– Small abrasives – better surface finish as well as they
can reach narrow and complex surfaces easily.
Machine Based
– Pressure - 0.7 Mpa to 22 Mpa (100 psi to 3200 psi)
Tauseef Shaikh, Asst. Prof., MPGI SoE
Nanded
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24. Capabilities of AFM process
• Surface finish in the range of 28 to 280
μm.
• Hole of 0.2 mm can be made.
• Dimensional tolerances achievable upto
± 0.005mm.
• Can reduce surface roughness by 75 to
90% on cast, machined or EDM sufaces.
Tauseef Shaikh, Asst. Prof., MPGI SoE
Nanded
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25. Application
1. Aerospace industry
– Improved surface quality
– Enhanced cycle fatigue strength
– Optimized combustion and hydraulics
– Increased airflow
– Extended component life
Tauseef Shaikh, Asst. Prof., MPGI SoE
Nanded
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26. Application
2. Automotive industry
• Enhanced uniformity and surface quality of finished components
• Increased engine performance
• Increased flow velocity and volume
• Improved fuel economy and reduced emissions
• Extended work piece life by reducing wear and stress surfaces
Tauseef Shaikh, Asst. Prof., MPGI SoE
Nanded
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27. Application
3. Dies and mold industry
• Reduced production costs
• Increased production throughput
• Enhanced surface uniformity, finish and cleanliness
• Improved die performance and extend life of dies and molds
Tauseef Shaikh, Asst. Prof., MPGI SoE
Nanded
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28. Application
4. Medical industry (Medical implants)
• Eliminate the surface imperfections where dangerous contaminates can
reside
• Improved functionality, durability and reliability of medical
components
• Enhanced uniformity and cleanliness of surfaces,
• Extended component life
Tauseef Shaikh, Asst. Prof., MPGI SoE
Nanded
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29. THANK YOU
Tauseef Shaikh, Asst. Prof., MPGI SoE
Nanded
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