Experimental investigations on the surface characteristics of abrasive waterjet-milled pockets in aluminium 6061-T6 alloy

Abstract

ABSTRACT Abrasive waterjet (AWJ) milling is suitable for generating pockets in difficult-to-machine ductile materials as the material removal is through local erosion with the exertion of minimal forces. However, the surface generated is non-uniform. The surface quality characterisation based on 2D profile parameters is insufficient to characterise the whole-milled surface. In this work, a region-wise surface characterisation approach is proposed and validated on Al6061-T6 material. The varying depth at jet start/stop (region 1), and jet traverse direction change (region 2) are qualitatively analysed. Following this, relatively flat central surface (region 3) is quantitatively characterised by 2D/3D surface roughness and waviness parameters. From the qualitative analysis, the mean depth at region 1 and region 2 is observed higher than the mean depth at region 3. The quantitative analysis at region 3 reveals that the surface quality improved in terms of surface waviness by ten times at lower waterjet pressures (P) and by two times at higher jet traverse rates (vf ). The surface roughness improved by 2.5 times at lower P, and roughness parameters found less sensitive to vf . Finally, from the results, it is concluded that the 3D characterisation with surface waviness as parameter suits better for AWJ milled surfaces.