Research And Experiment On Machining Parameters Optimization Of Ultrasonic Vibration Drilling

The ultrasonic vibration drilling(UVD)is one of non-traditional machining methods in which the ultrasonic machining and the traditional drilling(CD)are composited.In the UVD,which can effectively reduce the axial force of the tool and improve the forming effect of the hole.In this thesis,taking the titanium material as the object,holes are machined by tungsten steel tools in the UVD.The purpose of the thesis is to develope the theoretical research of the ultrasonic vibration drilling by simulation and experimental research.The main research contents include:(1)Based on the principle theories,the tool's kinematic characteristics and anti-friction characteristics of the UVD is studied.(2)The emphasis of the thesis is to analyze the axial force of the tool.With the professional software ABAQUS,the distribution of the tool's axial force is simulated.According to the simulation results,which is found that the axial force is effectively reduced by 40.45%compare to CD.Based on theoretical analysis of single factor,The axial force is found to be decreases with the increase of the spindle speed,and increases with the increase of the feed velocity and tool's angles Under the same machining factors,the axial force of the tool in the UVD is obviously less than that in the drilling.And in the UVD,the axial force is reduced with increasing vibration amplitude.Based on theoretical simulations of orthogonal factors,the influence degree in order is the tool's feeding velocity,the vibration amplitude,the tool's rotational speed and the tool's structure angles.And by simulations,the optimization machining parameters are predicted as follow:tool's rotational speed n is 4800r/min,feed rate f_zis15mm/min,tool's angle?is 100°,and the amplitude A is 4?m.(3)Experiments are performed on the experimental platform.When the ultrasonic frequency is set as 50KHz,the axial force of the tool is reduced by 23.51%in the UVD.The experimental results,in which the axial force of tool is reduced by ultrasonic effect,are consistent with theoretical simulations.And the experimental results are consistent with the theoretical analysis both in the single factor and the orthogonal factors methods.(4)The surface roughness Ra and roundness error of experimental workpieces are measured.The results show that the forming quality of holes in the UVD is better than the one in the drilling.Especially the average Ra values in the UVD are reduced by25.13%.A single factor experiment on the Ra value of surface roughness,Which is showed that axial force of two processing methods are decreases with the increase of the spindle speed,and increases with the increase of the feed velocity and tool's angles.The change of Ra in UVD is significantly lower than that of CD when the drilling parameters are changed,and increasing the amplitude will reduce the size of Ra values;According to the test results of the orthogonal experiment and range analysis,which shows that the order of the factors affecting the Ra values and the optimal parameter combination.The research significance of this paper is mainly to highlight the advantages of ultrasonic vibration in hole machining.Compared with CD,the axial force can be reduced,and the forming accuracy and surface quality of the hole can be improved.Selecting appropriate machining parameters or parameter combinations can reduce the impact on the drill.It has an important influence on the axial force and improving the surface roughness of the hole wall.