Study On The Milling Dynamic Characteristics And The Surface Quality Of Titanium Alloy Thin-walled Parts

TC4 titanium alloy thin-walled parts with excellent characteristics of light weight, high specific strength and good corrosion resistance are widely used in aerospace, marine, chemical industry and other fields. As the rigidity of thin-walled parts is poor, in the cutting process deformation and deterioration of surface quality will come out due to force and vibration. So in order to improve the machining quality and efficiency of TC4 titanium alloy thin-walled parts, it is of important significance to study on the dynamic characteristics and surface quality in the cutting process.In this paper, through the orthogonal experiment of milling TC4 titanium alloy thin-walled parts, cutting force, cutting vibration and surface roughness are studied along with the change of cutting parameters, and the empirical formula of cutting force is obtained. Using single factor experiment, the influences of different feeding positions on cutting force and vibration are analyzed, and the change law of the spindle vibration along with the change of spindle speed during spindle idling is analyzed. The milling vibration signals are analyzed in time domain and frequency domain. Through microscope the surface profiles and texture features of the workpieces machined are observed. The results show that:(1) The cutting force increases with the increase of feed per tooth, axial depth of cut and the radial depth of cut, and it fluctuates with change trend of the cutting speed; the biggest influence on cutting force is radial depth of cut; as feed position closes to the fixed end of thin-walled parts, the cutting force will increase.(2) The cutting vibration increases with the increase of spindle speed, and it fluctuates with change trend of feed per tooth, axial depth of cut and the radial depth of cut; the biggest influence on cutting force is spindle speed; as feed position closes to the fixed end of thin-walled parts, the cutting vibration will decrease; in the milling process, the vibration is mainly forced vibration.(3) The surface roughness increases with the increase of feed per tooth, it decreases with the increase of spindle speed and the axial depth of cut, and it fluctuates with change trend of the radial depth of cut; the biggest influence on surface roughness is feed per tooth.