Assessment of Cutting Force and Thrust Force in Lathe Orthogonal Turning of AISI-4140 Steel using Predictive Models

In engineering industries, where shaping of material to its size and specifications is constantly embarked on, machining is an extreme fundamental activity. The three most important machining operations are turning, milling and drilling. Turning operations require machine tool called lathe, and to impart the desired quality and accuracy into any turned part requires the application of suitable single point cutting tool. Once the cutting tool and workpiece is established, the cutting force then determines the production rate. This study, thereby focused on the development of predictive force models in orthogonal turning of AISI-4140 steel. The effect of depth of cut, feed rate, cutting speed and tool noise radius in relation to the responses was also investigated. In the process, turning operations were performed and the main cutting force and thrust force were measured with a lathe dynamometer. Both regression analysis and analysis of variance were used for data analysis. The minimum cutting force measured and predicted were 173.110N and 173.015N, respectively. For thrust force, the minimum evaluated and predicted values were 77.207N and 70.897N, respectively. From the data, regression models for the dependent variables were developed using Minitab. Feed rate was found to predominantly impact on main cutting force and thrust force. The coefficient of determination. values for both main cutting force and thrust force were 98.10 % and 98.93%, respectively. Also, results showed a good agreement between both data, which justified the capability of the models to predict the expected forces in turning AISI 4140 steel. It was found that depth of cut affected main cutting force the most, while feed rate has more influence on thrust force. Regression model is an adequate for thrust force and main cutting force analyses in orthogonal turning of AISI-4140 in dry environment.