ANALYSIS OF THE RELATION BETWEEN FRACTAL STRUCTURES OF MACHINED SURFACE AND MACHINE VIBRATION SIGNAL IN TURNING OPERATION

Abstract

Investigating about the machined surface is an important issue in every machining operation. One of the factors that affect the quality of machined surface is the vibration of machine that is caused by different parameters such as the spindle speed. Therefore, the analysis of the relation between the machine vibration and surface quality of machined surface is very important. In this research, we analyze the relation between the machined surface and machine vibration from the complexity point of view. For this purpose, we employ fractal analysis. We investigate the variations of fractal structure of vibration signal collected from lathe machine versus the variations of fractal structure of the machined surface, for different depths of cut, feed rates and spindle speeds. Based on the obtained results, the variations of fractal structures of machined surface and vibration signal show a similar trend with the variations of depth of cut and feed rate, where by the increment of depth of cut and feed rate, vibration signal and machined surface get more complex. However, the obtained results in the case of variation of spindle speed do not show a consistent trend between variations of fractal structures of vibration signal and machined workpiece. The obtained method in this research can be applied to other machining operations in order to analyze the relation between the complexities of machine vibration and machined surface.