Study of the correlation between surface roughness and cutting vibrations to develop an on-line roughness measuring technique in hard turning

Surface roughness is one of the important factors in all areas of tribology and in evaluating the quality of a machining operation. In order to achieve computer controlled machining in a flexible manufacturing system, a technique is needed for the on-line, real-time monitoring of each machining process parameter that affects surface roughness. As the first step in developing such an algorithm, research on the correlation between surface roughness and cutting vibration is reported in this paper. The algorithm utilizes the relative cutting vibrations between tool and workpiece, which are measured through an inductance pickup and filtered by an analog bandpass filter for a specific vibrational component. The cutting vibration signals of a specific frequency are superimposed onto the kinematic roughness, which is calculated by the tool edge radius and feed rate. Experimental results show good correlation between the simulated roughness obtained using the proposed algorithm and the roughness actually measured with a surface profilometer.