Evaluation of optimized surface characteristics in non-rotational sliding ball burnishing

Non-rotational sliding ball burnishing (NRSBB) was developed as a polishing process. The effect of NRSBB parameters on longitudinal and transverse roughness (Ra || & Ra ⊥), and microhardness (MHV) of AA7075-T651 face-milled plate was investigated by response surface methodology. Ra || decreased by increasing the ball diameter. Ra ⊥ increased with increasing the burnishing depth and step over. MHV was enhanced by increasing burnishing depth and passes. The optimal parameters obtained from multi-objective optimization were the ball diameter of 10 mm, burnishing depth of 0.18 mm, step over of 0.062 mm, five passes, and feed rate of 1050.3 mm/min. Compared with the face-milled surface, the optimized NRSBB improved Ra ||, Ra ⊥ and MHV by 93.7%, 89.3% and 37.3%, respectively. The topographic parameters of Sa, Sq, Sp and Sv improved by 89.3 %, 87.5%, 76.4% and 88.9%, respectively. The microhardness distribution of the optimized sample indicated 600 μm hardened depth.