Mechanics and dynamics of turn-milling operation

The turn-milling process is an emerging cutting technology that performs turning and milling operations simultaneously without changing the machine setup. It allows to produce big-diameter parts for difficult-to-cut materials and increases tool life due to intermittent contact between the rotating milling tool and workpiece. The uncut chip thickness between the tool and workpiece is a function of the multi-axes feed motion of all drives of the machine, the geometry of the tool and workpiece, and the contact area. Similarly, the regenerative vibrations that lead to stable and unstable (chatter) cutting conditions are altered due to simultaneous rotations of tool and workpiece and stability properties of the cutting operation become complex compared to conventional turning and milling processes. The most optimum cutting conditions must be virtually predicted to increase the material removal rate and at the same time keeping the surface quality requirements within allowed limits. This chapter proposes analytical models for the kinematics, mechanics, and dynamics of the turn-milling process and predicts geometrical errors and surface quality of the finished part.