Clamping Error Analysis And Surface Micro Morphology Prediction Of Micro Target Core In Ultra Precision Turning

As the matrix of the black cavity in the indirect driving mode of laser fusion target,the processing quality of the micro target core has a decisive impact on the processing quality of the black cavity,and also directly determines the success of the laser fusion device ignition.The machining accuracy of the target core is required to reach micron level,and the surface roughness is required to reach nanometer level.If the clamping and cutting methods are not properly selected,the surface machining quality of the target core can not meet the use requirements.Therefore,it is necessary to deeply analyze the clamping and positioning error of the target core,the error transmission of multi process machining and the cutting process,establish the micro morphology prediction model of the ultra precision machined surface of the target core,and realize the optimization of the cutting parameters.The research work has guiding significance for improving the surface quality of target core and black cavity.According to the stable clamping conditions in the process of ultra precision machining of target core,a special hydraulic expansion fixture for ultra precision turning of target core is designed.The clamping process of target core is analyzed by finite element simulation,and the variation of clamping deformation with clamping force and cutting force in the process of ultra precision turning is studied,Through comparative analysis of fixture stiffness,fixture deformation,residual stress and strain of target core in different types of fixtures,the special hydraulic expansion fixture for ultra precision turning of target core is optimized.This paper analyzes the source and transfer relationship of positioning error when the target core is clamped in the hydraulic expansion clamping,establishes the calculation model of the positioning error transfer chain of the target core,establishes the prediction model of the positioning error of the target core by using the small displacement screw theory,and verifies the correctness of the prediction model of the positioning error of the target core through the detection experiment of the positioning error of the target core.The source of error and its transmission rule in multi-process machining of target core are analyzed,emphasizing on the displacement error caused by the change of target core between different workstations,the relationship between the error and the installation error of hydraulic expansion fixture and the positioning error of target core is analyzed,and the relationship between the three is verified by the measurement experiment of target core displacement error.The critical cutting conditions and the selection range of cutting process parameters are determined.The vibration signal of machined surface profile is extracted by wavelet analysis,and the vibration signal is superimposed on the theoretical model of target core surface.The micro morphology prediction model of target core ultra precision turning surface is established,The prediction of surface micro morphology and optimization of cutting parameters before machining are realized.