Theoretical and Experimental Study of the Chatter Vibration in Dry and Wet Machining Conditions in the Turning Process

Turning is one of the most commonly used material removal processes. The self-excited chatter, which is one of the most common causes of cutting instability, decreases machining efficiency and surface quality extremely. The stable and unstable regions of the cutting are predicted by determining the stability lobe diagram (SLD). With the aid of this diagram and choosing the most suitable spindle speed and depth of cut a higher machining efficiency can be achieved. Despite the importance of cooling with cutting fluid, less attention has been paid to the effect of cooling on the chatter stability in machining processes. Therefore, in the present study, due to the importance of the subject, the chatter vibration in the turning process has been theoretically and experimentally investigated for two cooling conditions including 1- dry machining and 2- wet machining. First, a new model has been semi-empirically developed for prediction of turning force using Genetic Expression Planning (GEP). In this modeling, the turning force is obtained as a function of cutting parameters and cooling conditions. Then, the extracted force model is used to predict the chatter stability limit diagram (SLD) for two cooling conditions (dry & wet). In the next step, the SLDs have been evaluated by empirical data. The results of this research show that there is a good agreement between the SLDs and experimental chatter data. Moreover, the cooling with cutting fluid in the turning process has a significant effect on the displacement of the SLD.