Modeling of Cutting Forces During Machining
Machine tools are mechatronic systems. In a machining operation, the cutting forces determine the proper performance of the machine and the quality of the product. It is costly and time consuming to investigate the machining mechanism by carrying out experiments, especially for machining processes of costly work materials and advanced cutting tools. Modeling and simulation of a machining process can help predict process variables, which can lead to better control and improved performance, productivity, and product quality. Oxley’s comprehensive predictive machining theory has been used to predict the cutting forces, flow stress, and cutting temperature. His model assumes that the tool is perfectly sharp and the normal stress distributes uniformly at the tool—chip interface. These assumptions are not practical, particularly for high-speed machining. In this chapter, a new model is developed to predict cutting forces based on Oxley’s theory, but without such assumptions. In the proposed model, the machining process is simulated with the finite element method (FEM) and the constitutive flow stress model. From the simulation results, the shear stress, the shear angle, and the strain rate constant can be estimated, which are then used to predict the cutting forces. Experiments have shown that the model can predict the cutting forces with good accuracy.