Investigation of the size effect on burr formation in two-dimensional vibration-assisted micro end milling

Abstract

In precision and micro cutting processes, the tool cutting edge radius is generally quite large compared to the undeformed chip thickness, which can cause ploughing/rubbing between the tool and the workpiece and thus affect surface finish, tool wear, and burr formation. This paper investigates the effect of the size effect on top burr formation in two-dimensional vibration-assisted micro end milling (2D VAMEM). This is achieved by studying the effects of the ratio of undeformed chip thickness to the cutting edge radius, and the ratio of the time when the undeformed chip thickness is less than the minimum chip thickness to the total cutting time on top burr formation, using a model that integrates the chip thickness model of the 2D VAMEM and the minimum chip thickness prediction model. The corresponding experiments are carried out to verify the integrated model. It is found that feed per tooth has a significant effect on the height of the top burr, and the use of vibration-assisted cutting in micro end milling can minimize the size effect and improve the cutting performance, thereby reducing the height of the top burr. In addition, selecting suitable vibration parameters can significantly decrease the height of the top burr. The integrated model can be used to optimize the machining parameters to reduce burr size and further study the size effect on cutting force, surface roughness, and tool wear in 2D VAMEM.