Research On Cutting Force And Its Relationship With Tool Tip Radius In Laser Assisted Micro Milling

Ti6Al4V is widely applied in the aerospace industry, and it can be made into inertial navigation components and a variety of precision instruments. As its machinability is poor, the cutting force level of machining process is high and the cutting tool wears easily. Laser assisted micro milling is an effective and feasible method to deal with such a material which is hard to process, in which the milling force can be reduced effectively, and the tool wears slowly. Laser assisted micro milling force is studied in three aspects in this paper, i.e. theoretical model, the finite element simulation and the experiments. With the tip radius as one criterion for evaluating the degree of tool wearing, the tool wear condition in the process of laser assisted milling is explored. On the basis of analysis above, the relationship between cutting force and tool wear is also studied.In this paper the mechanics model of milling force in traditional micro milling process is established which is based on the classic milling force model. Then on this basis of the model above, laser assisted micro milling force model is constructed, in which the material mechanical properties and the influence of the radius of tool tip are taken into consideration. The material properties change as a result of temperature field change, and the tool tip radius changes as a result of tool wear.For laser assisted micro milling forces simulation in this paper, finite element simulation software ABAQUS is used. Firstly, von mises of the material under different preheating temperature are studied through 3d simulation. Secondly laser scanning simulation is conducted, and the simulation results show that in a very small zone the range of temperature change is small. Hence, non-steady temperature field of the cutting tool tip is simplified to the steady-state temperature field of the cutting tool tip. As a result, the non-steady state temperature field simulation is substituted by the steady-state temperature field simulation. Finally, the simulation results are combined with the 3d milling model, which results in the milling model in laser assisted micro milling, and the further simulation results are output. The milling force of the laser assisted micro milling is compared with its counterpart of the conventional milling.In micro milling experiments, the conventional micro milling and laser assisted micro milling experiments are conducted in this paper respectively. In those two groups of experiments, the milling force under different parameters is monitored real-time. The experiment results and theory of milling force model as well as finite element simulation of milling force model, verifies the correctness of the milling force and finite element simulation. Experiments show that cutting force grows with the increase of cutting distance. After the test of the tool tip radius used in the experiment, test results show that along with the cutting tool tip radius increases gradually with the distance increasing, which reflects the normal process of tool wear, and also indirectly reflect the has certain correlation between the cutting force and the cutting distance, as the similar changing trend appears. On this basis of the study above, the corresponding relationship between the cutting force and cutting tool tip radius is established, which is roughly a linear relationship. This result not only provides the basis for the further correction of laser assisted micro milling cutting force model, but also offers methods to the real-time monitoring tool wear situation with the milling force.