Extrude Hone / Abrasive Flow Machine (AFM)

What is an extrude hone? What does it do? How can I use it?

An extrude hone, also known as an abrasive flow machine, is a machine that performs a finishing process using a highly abrasive and viscous putty to polish, debur, hone, and radius material in a single operation. Rather than using an abrasive stone as other honing operations do, an extrude hone pushes this putty back and forth through a controlled passage until it is forced out–thus the name.

The abrasive flow machine can hone dozens of parts, holes, or passages at once, cutting down finishing times from hours of manual polishing to a 5-10 minute unmanned process. It is also strong on consistency, evenness, and tight tolerance-holding.

Extrude hones are most commonly used to remove burrs and thermal recast layers left behind by other secondary processes such as EDM or laser cutting. Users can expect to decrease roughness by 75-90%.

Most importantly, the extrude hone can finish complex or otherwise inaccessible areas simultaneously and blindly, without the need to split, finish, and re-weld parts.

For answers to your questions or more information on Extrude Hone machines call Liberty at 847-276-2761 or send us an email

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We are your #1 source for high quality extrude hones.

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Process Description: How does it work?

There are 3 major elements to the abrasive flow machine process: the tooling, the putty media, and the machine itself.

Tooling: Used to shape, constrict, and direct the flow of the media. This determines what part of the piece will be finished, since the abrasive action occurs at the points where the putty’s flow is most restricted.

Media: There are many different kinds of putty that vary based on viscosity, pattern, and abrasive aggressiveness. The putty perfectly conforms to the size and shape of whatever passage it is forced through. The media thus allows for a more consistent polish, since all surfaces are finished simultaneously.

Machine: The machine controls extrusion pressure, flow volume, and flow rate. The hone can operate on a one- or two-way system.

One-way systems flow the abrasive media through the workpiece openings in only one direction. This is generally accomplished from a top cylinder powered by a hydraulic ram. This allows the media to exit freely, or extrude, from the part for fast processing, easy cleaning, and simple quick-exchange tooling. This is especially desirable for making dies, since the polishing action occurs in the same direction as material flow, which can greatly extend the life of the die.

Two-way systems are more common. This method utilizes two vertically opposed cylinders, top and bottom. These cylinders are powered by hydraulic rams which extrude an abrasive media back and forth through passages formed by the workpiece and the tooling.

Common Industries

Aerospace     Automotive     Die-Casting     Plastic     Glass     Crystal     Vinyl     Aluminum

Common Processes:
  • ‘Sizing’ undersized die passages
  • Re-polishing used dies
  • Edge finishing
  • Freeing obstructions to maximize air, fuel, and exhaust velocity on aluminum intake manifolds & cylinder heads
  • Improving airfoil surface conditions
  • Adjusting air flow resistance
  • Removing coke and carbon deposits
  • Finishing accessory parts

Major Extrude Hone/Abrasive Flow Machine Manufacturers

Bosch Surftran, Dynetics, Extrude Hone, Kennametal, Lapmaster Wolters, Winbro

Sell Your Abrasive Flow Machine

Liberty is always looking for used extrude hones and abrasive flow machines to buy for inventory. Contact us and let us know what you have for sale. We’ll be happy to give you a free quote.

Check our Inventory for a Used Abrasive Flow Machine

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See our used extrude hones (AFMs) for sale.

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  1. Extrude Hone: Automatic Die and Mold Polishing. Extrude Hone Corporation, Irwin, PA (n.d.).
  2. Extrude Hone. Extrude Hone Corporation, Irwin, PA (n.d.). Extrude Hone website.
  3. pamphlet. Extrude Hone Corporation, Irwin, PA (n.d.). Website. Extrude Hone.