Research On Vibration Assisted Polishing Technology And Device For Structural Surface

As one of the most promising advanced processing technologies,vibration assisted processing technology is widely used in ultra-precision machining of free-form surfaces with complex structures.Three-dimensional vibration devices based on this technology are often used as vibration aids to improve the machining performance of conventional equipment for processing a variety of difficult-to-machine materials as well as ultra-precision microstructure surfaces.In the continuous development process of vibration assisted processing technology,higher requirements are placed on accuracy and efficiency.In response to this demand,this paper designs a three-dimensional vibration assisted machining system to realize complex structural surface processing.The main research contents are as follows:(1)In order to improve the accuracy of the vibration aided machining system and avoid the force disturbance in the machining process,two kinds of three-dimensional vibration devices are designed in this paper.One of them has simple control,high relative output stiffness,and the other has high operation accuracy.The static model of the three-dimensional vibration device is established by the full compliance matrix method(MCM)and the finite element method,and the input and output stiffness of the three-dimensional vibration device are evaluated.Then,the kinetic analysis was performed using the energy method,the finite element method,and the experiment to evaluate the natural frequency of the device.The device is used to assist the CNC machine tool to build a three-dimensional vibration assisted machining system.(2)For the processing of structural surfaces,this paper proposes a processing path planning method for structural surfaces,and explores the main factors affecting the machining path of the workpiece surface,mainly involving factors such as frequency,amplitude and phase difference.The influence of vibration parameters on the output trajectory of the device is discussed by simulation,and the influence of various factors on the surface coverage and uniformity of the workpiece surface machining path is described.This paper proposes a tool path planning method,establishes a mathematical model between machining path and tool path,reveals the influence of different tools and workpieces on machining path,and verifies the universality of tool path method.Finally,the theoretical model of vibration assisted surface machining is established,and the influence of various factors on the shape and size of the structure is discussed.(3)The main performances of dynamics,output response,linear performance and decoupling performance of the three-dimensional vibration device,the core component of the three-dimensional vibration assisted machining system,were tested by experiments.Experiments show that the dynamic performance is consistent with the theoretical dynamics simulation performance.The device has high precision and sensitivity and is suitable for applications under stress conditions such as machining.Several common spatial trajectories were tested.In addition,three-dimensional vibration-assisted scoring and three-dimensional vibration-assisted milling and polishing experiments were carried out using the established three-dimensional vibration assisted machining system.Surface textures with a distinct periodic structure were successfully fabricated on aluminum workpieces.In this paper,the theoretical analysis and simulation research on the 3D vibration assisted machining system are carried out.The main conclusions are as follows:(1)The three-dimensional vibration device designed in this paper has high output stiffness,high precision and high output frequency compared with the traditional micro-motion device.The feature is that it can reduce the problem of disturbance of the output end.(2)The new three-dimensional vibration device designed in this paper.It has an axially symmetric structure,which is characterized by its axisymmetric form in mechanical properties.In addition,the axisymmetric structure is beneficial to the improvement of the running accuracy of the device.Piezoelectric ceramics are fixed to the frame,which reduces the motion quality and makes it have a high natural frequency.(3)According to the path planning method and tool path generation method for the establishment of structural surface machining,the theory of structural surface generation is proposed,and the internal relationship between machining parameters and structural forming is revealed.