Robotic Machining Simulation using a Simplified Multibody Model

Robotic machining is a promising manufacturing technology combining the agility of an industrial robot with the potential of a net shape process. Nowadays, robotic machining is springing up everywhere. A large number of companies attempt the conversion of their process using this technology, but without great success. Indeed, the material removal using a robot is very different from the conventional milling. Even though it is cheaper for a larger working envelope, the understanding of robotic process must be widened in order to overcome technological hurdles. Among them, the lack of stiffness at joints and the inherent low frequency structure are mainly accountable for the quality depletion of the machined workpiece. The simulation of an industrial process can be an interesting approach to better perceive the on-going phenomena during the machining phase. For this reason, a multibody modelling of a robot coupled with the simulation of milling was implemented. The robot was modelled as an anthropomorphic arm comprising 4 degrees of freedom and including the joint stiffness. Results were finally confronted with experimental data in terms of cutting forces, vibrations and roughness for which a good accordance could be observed.