Research Of Milling Force And Surface Integrity In Ultrasonic Assisted Milling Of Nickel Alloy

Nickel alloy is widely used in the manufacture of high temperature parts for its good thermodynamic properties,high strength,and high hardness.At present,the traditional mechanical is often used in the processing of nickel alloy,which is difficult to achieve high quality and high efficiency.Ultrasonic vibration assisted machining technology applies ultrasonic vibration to the tool or workpiece on the basis of ordinary machining,and realizes high-frequency intermittent cutting.It has the advantages of reducing the macro cutting force,improving the processing environment,and improving the quality of the processed surface,so it is mostly used in the processing of hard and brittle materials.In the past,most of the ultrasonic assisted cutting technologies applied ultrasonic vibration to the workpiece,while the research on axial ultrasonic vibration to the tool is less.Therefore,this paper takes nickel-based superalloy as the research object,and the axial ultrasonic vibration assisted milling experiments are carried out.The simulation software is used to simulate the ultrasonic vibration assisted milling process,and the influence of ultrasonic vibration on milling force and surface integrity is analyzed.The main work is as follows:(1)According to the characteristics of ultrasonic vibration,the working principle of ultrasonic vibration machining is analyzed.After the kinematic analysis of the cutting tool,the different motion paths of the traditional milling tool and the ultrasonic vibration milling tool are compared,and the ultrasonic vibration assisted milling force model is established according to the cutting principle.The key models of finite element analysis are introduced theoretically,and the simulation analysis software is used to simulate the axial ultrasonic assisted milling process.The milling process is simplified and a three-dimensional cutting model is established.In order to study the relationship between milling force and ultrasonic vibration amplitude and frequency,and determine the reason of reducing milling force assisted by ultrasonic vibration,single factor and multi factor orthogonal simulation cutting experiment are designed.(2)Taking nickel-based superalloy as workpiece material,the comparative experiments on milling force of conventional milling and ultrasonic vibration assisted milling are designed.In the single factor experiment,the influence of different milling parameters on the milling force is analyzed by setting different milling parameters.By designing multi factor orthogonal experiment and using multiple linear regression analysis method,the exponential model of milling force empirical formula is established,and the reliability of milling force prediction model is verified by specific experiments.The range of milling force and component force are analyzed to determine the milling process parameters which have the greatest impact on them.(3)The correlation between milling force and surface roughness and between milling force and material removal rate are studied.According to the corresponding milling parameters and experimental results,the correlation between milling force and surface roughness,as well as between milling force and material removal rate are analyzed by using qualitative analysis and Pearson correlation coefficient quantitative analysis.(4)The ultrasonic vibration-assisted milling experiment is carried out with the help of white light interferometer and microhardness tester.The influence of ultrasonic vibration on the surface integrity is studied with the characterization parameters of line roughness,surface roughness and surface microhardness as the evaluation objects.After the range analysis of the experimental results,the influence of the ultrasonic vibration assisted milling parameters on the surface integrity is determined.In order to obtain the optimal milling force,surface roughness and microhardness,the experimental results are optimized according to the multi-objective machining parameter optimization method.After optimization,the ideal process parameters can be obtained,and the feasibility of the optimal target interval is verified by experiments.