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The surface machining mechanism of 3-D ultrasonic turning technology is studied by using the single-excitation 3-D ultrasonic assisted vibration device. Firstly， the simulation model suitable for 3-D ultrasonic cutting is designed by establishing the trajectory equation of the tool tip， and the simulation orthogonal experiment is designed. The influence of spindle speed， cutting depth and feed rate on surface morphology in 3-D ultrasonic turning process is studied by the multiple comparative analyses of variance. Then， the surface processing quality of 3-D ultrasonic turning and ordinary turning is compared through experiments， and the influence of processing parameters on 3-D ultrasonic turning and the optimal parameters are studied. The results show that compared with ordinary turning， 3-D ultrasonic turning can obtain better surface processing quality， and the influence of feed rate on surface roughness is the most significant. The optimal processing parameters are spindle speed 200r/min， cutting depth 0.12mm， and feed rate 0.18mm/r. [ABSTRACT FROM AUTHOR]

In order to solve the problems of poor surface quality and easy to produce burrs in the traditional forming process of 304 stainless steel, a new type of three-dimensional ultrasonic vibration cutting device was designed and tested. Firstly, through the analysis of the geometric deformation relationship of the device structure, the theoretical motion trajectory model of the tool tip is established. The trajectory model is fitted by Matlab and the actual output trajectory is simulated by ANSYS. The tool tip motion trajectory is a three-dimensional parabola in space. Secondly, the cutting experiment with or without ultrasonic vibration was carried out on the device， and the machined workpiece surface was measured and observed by the super depth of field system and the three-dimensional profiler. It was found that the arithmetic average height of the machined surface roughness under ultrasonic vibration cutting is significantly lower than that of the ordinary turning. The results show that ultrasonic vibration cutting has better machinability for 304 stainless steel than conventional turning. [ABSTRACT FROM AUTHOR]

In order to improve the machining effect of 304 stainless steel， reduce the cutting force and prolong the tool life， a turning process combining micro-texture tools and three-dimensional ultrasonic vibration is proposed. Based on the orthogonal cutting model， the cutting force model for three-dimensional ultrasonic vibration turning of ordinary tools and micro-texture tools are established from the perspective of variable depth of cut and reduced contact area of micro-texture tools， using the friction reduction and interrupted cutting characteristics， respectively. The influence of various cutting parameters on the main cutting force was studied through the single-factor experiment of turning 304 stainless steel and comparing the tool wear. The optimal cutting parameter combination was studied through the orthogonal experiments. The results showed that compared with ordinary tools， the main cutting force of the micro-texture tool was reduced by 30%~40%; the wear degree was reduced by 11.50% on average; for reducing the cutting combined force， the best combination of cutting parameters is that the cutting depth is 0.1mm， the feed rate is 0.08mm/r， and the spindle speed is 250r/min. [ABSTRACT FROM AUTHOR]

A CW laser was used to perform laser polishing experiments on the 304 stainless steel based on the ablation principle， and a good polishing effect is obtained. A two-dimensional transient numerical model was developed by coupling the heat transfer and material vaporization in laser polishing. The evolution of the workpiece surface in laser polishing was simulated. The surface morphology and surface roughness of the workpiece after laser polishing were predicted. The simulation results are close to the experimental ones， and the error is only 8.17%. In addition， this paper studied the distribution of the surface moving velocity of the workpiece in laser polishing， and determined the relationship between the surface moving velocity and the initial surface morphology: the surface moving velocity at the peak position of the surface morphology is larger， while the surface moving velocity at the valley position is smaller， which reveals the mechanism of laser polishing based on ablation principle to reduce the surface roughness of the workpiece. [ABSTRACT FROM AUTHOR]

An axial ultrasonic vibration assisted drilling method was proposed for solving problems such as difficulties in chip breaking， chip removal and poor processing quality in traditional drilling process. Motion characteristics and chip breaking mechanism were studied， and the comparative tests of conventional drilling and axial ultrasonic vibration assisted drilling were performed on the 45# steel using an own-designed axial ultrasonic vibration assisted drilling system. Investigations were done toward the machining precision of holes， surface morphology and the shape of chips. The experimental results demonstrate that axial ultrasonic vibration assisted drilling can effectively reduce the surface roughness and improve the microscopic morphology compared with the traditional processing. In addition， variance analysis is used for data processing， indicating that the spindle speed and ultrasonic amplitude have significant influences on the surface roughness， and the processing effect is best when the amplitude is 20μm and spindle speed is 450r/min. [ABSTRACT FROM AUTHOR]

In view of difficulties in drilling high-temperature alloys and large friction during drilling， ultrasonic machining was used. Firstly， the reducing friction mechanism of ultrasonic vibration was analyzed， the relationship between the average friction force and vibration parameters was constructed， and then the correlation between the average friction force and amplitude was obtained. An axial ultrasonic vibration drilling system was established， which was used to drill the superalloy. The results showed that the effect of amplitude on the surface quality of hole wall is consistent with anti-friction characteristics of ultrasonic vibration. Compared with that of the ordinary drilling， the production of optimized amplitude ultrasonic vibration drilling yields more regular chip morphology， smooth hole wall surface roughness， and better surface quality. [ABSTRACT FROM AUTHOR]

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In view of helical drill point grinding， the theoretical and experimental bases for grinding the required geometrical parameters of helical drill points are presented in this paper based on the optimization of biglide parallel machine grinding parameters. A method of grinding the involute helical surface based on the biglide parallel machine is introduced， and then the mathematical model is derived for the helical drill flank. Moreover， the relationship between the geometric parameters and grinding parameters is analyzed， and the optimal grinding parameters are acquired based on genetic algorithm. The results showed that the optimized grinding parameters improve the grinding precision with the experiment on the biglide parallel machine， and the biglide parallel machine can satisfy clients' demands of drill grinding. [ABSTRACT FROM AUTHOR]