Simulation of chip formation for varying uncut chip thickness during vibration-assisted drilling with the CEL method

Vibration-assisted drilling is particularly efficient for long-chipping and difficult-to-machine materials due to its special kinematics with interrupted cutting. In order to optimize the process, a deeper understanding of the occurring external and internal material loads is required. For this purpose, a model is developed and simulation results are compared with experimental data on the materials Ti6Al4V and AISI 4140. Based on a kinematic simulation, individual segments on the main cutting edge are considered and the local chip formation is modelled as an orthogonal cut using the CEL method. Special consideration is given to the process kinematics, where, in addition to the entry and exit of the tool cutting edge, a varying uncut chip thickness occurs. Drilling without vibration assistance is also modelled in this way. The resulting drilling torques and thrust forces are compared with experimental data. The experiments are carried out on tubes with different internal diameters to represent the different segments of the main cutting edge. In addition, experimental results on drilling a rod and into solid material quantify the effects of the chisel edge and the minor cutting edges. The results show that both drilling and vibration-assisted drilling can be modelled using orthogonal cutting models with acceptable computation times.