Investigation of Controlled Vibratory Drilling Dynamics with Variable Velocity Feedback Gain

During drilling, swarf can block tool’s clearance channel and lead to a standstill of production job. That is why it is advisable to make a drill bit oscillate in the axial direction. The certain amplitude–phase relation guarantees chip breakage. One of the ways to ensure this kind of vibration is to include in the system of tool fastening the special elastic element, characteristics of which are chosen from conditions of axial self-excited vibration excitation in the technological system. It is appropriate to add the control response, which sustains the tool vibrations in a wide range of manufacturing process parameters. In this paper, the model of vibratory drilling dynamics with velocity feedback is given. The possibilities of setting velocity feedback gain as constant and periodical laws have been investigated. The relation between integral characteristics of vibrational process and these laws parameters have been plotted. It is shown that the vibrational characteristics in case the feedback gain is set as a periodical function cannot be achieved in any way if the feedback gain is a constant.