Finite element simulation and experimental analysis of robotic boring based on an approach of equivalent stiffness

Robotic boring is an effective way to implement finish machining of intersection holes. However, to a certain extent, its application is limited due to the low rigidity of the robot, whose stiffness brings on high vibration levels. In this study, a new approach based on an equivalent stiffness is proposed to gain a fundamental understanding for the cutting mechanism and vibration performance of a robotic boring system. In the approach, the robotic boring system in one direction is regarded as a mass–spring–damping unit according to the structure characteristics of the robot. Thus, the whole robotic boring system is equivalent to a mass–spring–damping group in three-dimensional space. The stiffness and natural frequency of the robot system were measured by stiffness identification and a modal test on an ABB IRB 6600-175/2.55 robot. An equivalent three-dimensional finite element model based on this approach was established to simulate the robotic boring process, and a verification experiment was conducted to determine the accuracy of the finite element simulation. The results show that the simulated cutting force components and the amplitude in the feed direction are in good agreement with the experiment under different cutting conditions, and this proposed approach is feasible.