Experimental study of cutting forces and surface topography in three-dimensional vibration-assisted milling for fabricating structured surfaces

In the vibration-assisted milling process, the cutting force as a very important parameter can reflect the cutting characteristics of this machining method. In this study, a three-dimensional vibration-assisted milling system was utilized to focus on the changing law of the cutting forces and the topography of the structured surface during machining. Firstly, the kinematic analysis proves that the trajectory of the tool relative to the workpiece under the excitation of the vibration device is a complex spatial spiral curve. Then, many vibration-assisted milling experiments were carried out to investigate the effect of the process variables, such as the spindle speed, feed rate, amplitude of vibration, vibration frequency, and tool radius, on the cutting forces (average and maximum cutting forces) and the topographical characteristics of the structured surfaces. The experimental results sufficiently confirmed that the amplitude of vibration is the most important process variable associated with the cutting forces, followed by spindle speed and vibration frequency; for the topographic features of the structured surface, the amplitude of vibration also has an important effect on the three-dimensional dimensions of each structural unit; by contrast, the vibration frequency and the feed rate do have a significant effect on the topography of structured surfaces. The results of the research provide critical guidance for 3D vibration-assisted milling to fabricate a variety of structured surfaces.