Experimental numerical model of roughness in finishing face milling of AISI 4140 hardened steel

Abstract

This work is based on the roughness analysis of a hardened steel, AISI 4140 quenched and tempered with 58HRC, during an end milling process executed with a CBN (cubic boron nitride) tool, obtained by varying three basic cutting parameters (cutting speed, feed and cutting depth). It was decided for the experimental planning, to use a central composite design, widely applied in research related to machining experiments. The results were statistically processed by the software “Statistica”, enabling the generation of a mathematical equation to predicted the surface roughness value due to the optimization of the three cutting parameters adopted. The surface roughness results are in the range of 0.16–0.4 Ra. Two numerical models were created using the NLREG software confirming the interaction of the cutting parameters with the roughness. The cutting parameter with the most influence on the surface integrity during the end milling process was the feed per tooth.