WET EDGE FINISHING OF NATURAL STONES: INFLUENCE OF TOOL GEOMETRY, GRIT SIZE AND CUTTING CONDITIONS ON POLISHING FORCES

The tool performance, durability and part quality during granite edge finishing depend strongly on the cutting forces generated at the tool-workpiece interface. This paper focuses on analysis of cutting forces during CNC wet edge finishing of granites using four industrial profile tools (Eased Concave (CO), Eased Chamfered (CH), Half Beveled (HB) and Ogee (OG)) and four abrasive grits (G45, G150, G300, G600). Experiments were performed on a 3-axis CNC machining center with flooded fluid (water/mineral-oil emulsion) and forces were measured with a three-component dynamometer. A mixed design of experiments was employed and the data was analyzed using analysis of variance (ANOVA) and response surface methods. Results show that tool geometry and grit size are dominant factors for forces, with spindle speed also highly significant for the axial force Fz and the combined in-plane force Fxy. Black granite systematically produces higher Fz than white granite across all grits, whereas Fxy reveals a brittle (G45–G150) to ductile (G300–G600) transition with material-dependent friction regimes. Targeted models of Fz and Fxy on black granite confirm that spindle speed is the predominant driver of force levels, while feed rate alters both magnitude and stability depending on the tool.