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Abrasive Flow Machining — AFM

In its most basic terms, Extrude Hone’s Abrasive Flow Ma-chining process (AFM) can be thought of as a grinding stone that has come alive. The media used in the AFM process acts as a self-forming le that will conform to the exact shape of the surface or passage that is to be processed. Polishing, deburring, and edge radiusing are accomplished anywhere that the media can be forced to ow. The result is a surface nish quality that cannot be matched using traditional nishing methods. Workpieces with inaccessible areas that were previously impossible to reach are typical applications for AFM. Workpieces made from a wide range of materi- als—from soft aluminum to tough nickel alloys, ceramics and carbides—can be successfully machined using the AFM process. THE MEDIA The central element of the AFM process is the media, a polymer carrier mixed with abrasives. The viscosity of the carrier, the abrasive particle size, and the abrasive type and concentration can all be varied to achieve specic nishing results. When the media is forced into a restrictive pas- sage, the viscosity of the media rises, holding the abrasive particles rigidly in place. The media abrades the passage through which it ows only when the in this restricted state. The viscosity returns to normal when the thickened portion of the media exits the restictive passage, producing no abrasion on areas such as threads or seal surfaces. THE TOOLING
Tooling used in the AFM process holds the workpiece in position and directs the ow of the media to appropriate areas. Many applications require only simple tooling; extru- sion dies typically need no special tooling, the die passage itself provides the restriction for the media ow path. For external edges or surfaces, tooling is used to restrict the ow between the outside of the part and the inside of the xture. The tooling may also serve to restrict ow at areas where abrasion is desired or to block the ow through areas that are to remain unaected. THE MACHINE
The Extrude Hone machine is available in a variety of sizes and congurations. the typical machine contains two verti- cally opposed media cylinders which hydraulically close to hold a part or xture between them. By extrudeing the abrasive media from one media cylinder to the other, a honing action is produced whereever the media enters and passes through a restrictive passage.

for more information about Extrude Hone’s unique nishing equipment and contract shop services… Extrude Hone Corporation

1 Industry Boulevard • P O Box 1000 • Irwin, PA 15642 800-367-1109 • 724-863-5900 • Fax 724-863-8759

www.extrudehone.com