Investigation on the vibration and machined surface quality in tilt side milling of thin-walled plates

Abstract

Tilting milling tools to proper angles could help significantly suppress machining vibrations and enhance machined surface quality. The aim of this study is to investigate how the two fundamental variables, tool helix angle (β) and tilt angle (θ), could influence milling vibrations and machined surface topography when milling sidewall surfaces of thin-walled plates with solid end mills. A series of side milling tests were carried out at different tilt angles utilizing tools with different helix angles, during which the accelerations, instantaneous vibration displacements, cutting forces, machined surface roughness, and topographies of the workpiece were carefully measured. The results showed that the minimum machined surface roughness across the measured surface, Ra, was 0.37 μm when β = 40° and θ = 30°. In addition, optimal tilt angles for the lowest Ra on the machined surface with tools of different helix angles are in accordance with the optimal angles for the minimum absolute value of Z-axis force Fz, rather than ones for the weakest vibrations. This result indicates that, when milling sidewall surfaces of thin-walled plates, Ra is more highly dependent on the cutting force component along the lowest stiffness direction of plates than the vibration amplitudes. The results presented in this paper are useful insights for milling process parameter optimization to improve machined surface quality in milling sidewall surfaces of thin-walled components.