An extrude hone, also known as an abrasive flow machine (AFM), uses 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.
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 extrude hone 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 extrude hone 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.
For answers to your questions or more information on Extrude Hone machines call Liberty at 847-276-2761 or contact us.