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Abrasive Filament Brush DeburringofPowdered Metal Components

D. Mark FultzVice President MarketingAbtex CorporationDresden, NYThe deburring of PM parts is commonly performed in a batch process. This typicallyinvolves loading a quantity of parts into a vibratory bowl filled with abrasive media. The vibration of the bowl causes the abrasive media, and parts, to “flow”. This interaction between the media and parts gradually abrades all surfaces of the part. Drawbacks to this process include part impingement upon one another, waste generation, lodging of media into the part, deburring of unnecessary areas on the part and the inherent vibration and noise created by the operation of these systems.This paper discusses an abrasive filament medium which is ideal for deburring and edgeradiusing PM parts. When formatted into a brushing tool, it can be applied on machine based systems for semiautomated or fully automated deburring of PM components. Through proper application, it is possible to gain the advantages of productivity, quality, and economics without the negatives associated with alternative methods. FIBER ABRASIVES The term “fiber abrasive” is used to describe an abrasive nylon filament. Developedapproximately 25 years ago, they are commonly employed in brush form for a variety of industrial applications. These generally involve deburring, edge radiusing and general surface finishing.The filament is composed of nylon, which has been coextruded with an abrasive grain.The resulting monofilament is a homogeneous structure of nylon and abrasive. Nylon is an ideal material for a brush filament. Compared to other polymers, it excels not only in its durability, but also in its resistance to moisture, abrasion and chemicals (1). Nylon types used in the production of fiber abrasives are Type 6, Type 66 and Type 612. Type 612 is preferred in industrial applications. It offers the greatest heat resistance and least amount of moisture absorbency.The grain, or grit, is impregnated throughout the filament as well as exposed on theexternal surfaces. A magnified example of this filament is shown in figure 1.