Effects of natural rock properties on cutting forces, specific energy and specific cutting energy by four-axis machine

Abstract

This study used a four-axis machine to investigate the processability of natural rocks and parameters affecting cutting forces (Cf), specific energy (Se) and specific cutting energy (Sc). A total of 12 types of natural rocks (7 marbles, 3 travertines, and 2 limestones) were categorized according to their geological formations and subjected to various characterization tests (petrographic characteristics, chemical properties, and physical and mechanical properties). This study consisted of three parts: (1) experimental measurement of cutting forces resulting from processing natural rocks using a 6.0-mm-diameter end mill cutting tool and a four-axis machine; (2) calculation of tangential cutting force (Fc), radial cutting force (Ft), specific energy (Se) and specific cutting energy (Sc) values; and (3) statistical analysis of parameters. For processability, cutting parameters at different levels (depth of cut and feed rate) were used to mill samples of different natural rocks. Statistical analysis (ANOVA) was performed on Cf, Se, and Sc values depending on the depth of cut and feed rate. Results indicate that depth of cut (1.2, 1.6, 2.0 mm) and feed rate (2000, 2500, 3000 mm/min) are important cutting parameters in the processability of rocks. A simple linear regression was performed to examine the relationship between physical and mechanical properties, and between Cf, Se, and Sc values. The coefficient of determination value (R2) is ≥ 0.821. The physical and mechanical properties of natural rocks are important parameters in the estimation of Cf, Se, and Sc values.