A case study on the abrasive surface finishing of aluminum flat sheet

Abstract

A case study of a unidirectional abrasive metal removal process applied on aluminum flat sheet in manufacturing processes is presented. A series of tests were conducted using belt type abrasive media of varying equivalent grit sizes on both bare and clad aluminum flat sheet. Samples were processed through each media in the longitudinal, transverse and angular orientations with respect to the rolling direction to quantify and qualify the metal surface as well as the abrasive media. In clad aluminum, a layer of pure aluminum metallurgically bonded to a substrate by rolling process, is used for appearance and corrosion resistance in aircraft component applications. An optical microscope was used to investigate the relationship between the equivalent grit sizes of the abrasive media and the maximum penetration depth into the clad layer after the directional abrasive process. Measurements of groove depths on the edges of the 2024 clad aluminum sheet samples were conducted after processing through abrasive belt media of equivalent abrasive grit sizes, varying from 180 to 320. It was found that any abrasive belt media with equivalent grit size below 320 may be inappropriate to process clad aluminum sheet due to penetration of the abrasive into the clad layer which can expose the substrate aluminum alloy to the atmosphere.