Theory And Experimental Study On High Speed Milling Titanium Alloy

Titanium alloy find more and more applications in many industrial fields especially in national defence industry because of their excellent performance. However, titanium alloy is well known as a difficult-to-machining material, because of its low thermal conductivity, small elastic module, and high chemical activity, induce cutter abrasion easily. so how to improve its machining efficiency has been turned into an urgent problem. Research indicates: high speed machining is an effective method of solving this problem.Under the natural science foundation of Hunan province(05GK3021) and Science and Technology Planned Project of Hunan province (05JJ30080). In this paper, high speed milling mechanism and technics of titanium alloy TC4 is more systematically studied by theory and experimental research on the base of in-depth investigation and research on development of high speed machining and high speed milling of titanium alloy at home and abroad. Chief works finished are as follows:The milling force model is set up by means of analysis;The rules of affecting of milling parameters (spindle speed, milling depth) on milling force are analyzed by means of the single factor experiment. The single factor empirical formula of milling force is fitted;The rules of integrated affecting of milling parameters (spindle speed, milling depth) on milling force are analyzed by means of the orthogonal experiment. The predictive model of milling force is set up;The rules of affecting of milling parameter (milling speed, milling depth and feed rate) on surface roughness of the workpiece are analyzed by means of the single factor experiment. The single factor empirical formula of surface roughness is fitted;The rules of affecting of milling parameter on surface roughness of the workpiece are analyzed by means of the orthogonal experiment The predictive model of surface roughness is set up;The new modality of chips observed by SEM is analyzed by means of the adiabatic Shearing theory, and the own opinions on mechanism of chip forming is put forward.The following conclusions can be indicated of this paper:1,Less milling force and lower workpiece surface roughness is notability advantage of high speed milling TC4, the reasonable cutting condition must be chosen according to the technic condition, at the same time of ensuring the surface quality, the balance of work efficiency and produce cost are acquired.2,The photos of chips are observed by SEM, is sawtooth , plasticity deformation of cut layer metal that is mainly shearing slippage is caused by sudden change of local stress within chip, is the typical adiabatic shear, and the width of adiabatic shearing is correlation with milling parameter.The research has definite academic value in research of high speed milling mechanism and engineering application. The experimental data and conclusions have some referrence value in establishing the high speed milling technic database for the future.