Study on the Effects of Miniaturization on the Vibrational and Stability Behavior of Milling Machines

Improvements in manufacturing technology in recent years have granted the manufacturers a chance to produce tiny mechanical parts. To produce such small parts, it is convenient to use small machine tools, as large as they can be installed on a table. Such machine tools are called desktop machine tools. These downsized machines are of interest because of they occupy less space and consume less energy and coolant fluid. Aspects of desktop machine tools have been studied in the previous works, but questions still remain about the performance of these machines especially from the viewpoint of their vibrational behavior. Vibration of a machine tool affects the surface of the workpiece and lowers its quality. Moreover, it may lead to chatter vibrations which results in unstable cutting process, poor surface quality and possible damage to tool, workpiece or spindle. Hence it is imperative to study the vibrational and stability behavior of desktop machine tools in comparison with conventional machines, under similar tool and cutting conditions. In this paper, a dynamic model is presented and used to determine the frequency response functions and stability diagrams of the machines. Then, with the help of dimensional analysis, the behavior of miniaturized machine is compared with its conventional size counterpart. Studies show that the amplitude of vibrations changes by miniaturization depending on the machine size, the tool size and the excitation frequency.