Design And Research Of Precision Machining Device For Complex Deep Hole Internal Contour

With the increasing requirements for weight reduction and efficiency of sophisticated equipment in energy,power,aerospace and other fields,a large number of bottle hole parts with high manufacturing difficulty and demanding performance indexes have emerged,which have large length-to-diameter ratio(L/D > 10)and complex internal contour(the existence of bottle cavity,profile and keyway).When using the traditional boring bar to machine bottle holes,it often faces technical problems such as weak tool rigidity,low machining efficiency and difficult to guarantee the dimensional accuracy of the workpiece.To this end,this paper designs a deep hole internal contour precision machining device(deep hole internal contour tool)with strong guiding and supporting ability,small transmission clearance of variable diameter,and constant drive ratio of the tool head,which can realize the machining of arbitrary rotary-shaped internal contour of bottle holes and provide some technical support for the machining of bottle holes.The main research contents of this paper are as follows:(1)The special deep hole internal contour tool is designed for the machining of bottle holes.The structural design and parts selection of the deep hole internal contour tool are carried out,and the analysis of bevel self-locking,guide pads arrangement,tool bar modeling and chattering stability analysis of the tool are completed,which provide a reference basis for the design of deep hole internal contour tool,and the corresponding deep hole internal contour machining system is designed on this basis.(2)Based on cutting simulation,regression analysis and genetic algorithm,the cutting parameters are optimized and analyzed.The influence law of cutting parameters on cutting force and cutting temperature was analyzed by response surface method,and the regression prediction model of cutting parameters and cutting force and cutting temperature was established.Based on the above regression prediction model,a multi-objective optimization of cutting force Fx and material removal rate Q was carried out based on genetic algorithm to obtain the Pareto set of cutting parameters,and the evaluation indexes of tool wear,chip morphology and surface topography of the finite element model under one set of cutting parameters were analyzed.(3)Based on the finite element structure simulation,the applicable parameters for the bevel angle of mandrel,the number of cam keys and the number of guide pads of the deep hole internal contour tool were obtained.The cutting force under the selected cutting parameters after parameter optimization is taken as the load,and the static and dynamic load analysis is carried out by the finite element software for the tool head with different bevel angle of mandrel and number of cam keys,and the guide support analysis is carried out for the deep hole internal contour tool with different number of guide pads,and the applicable parameters for the bevel angle of mandrel,number of cam keys and number of guide pads are obtained.And the excitation frequency to be avoided during the machining process was obtained by the modal analysis and harmonious response analysis.(4)The feasibility of the deep hole internal contour tool was verified by deep hole internal contour boring experiment.Based on the selected cutting parameters after parameter optimization and the introduction of the segmented and layered pull-boring process,the deep hole internal contour boring experiment of TC4 pipe was carried out with the trial deep hole internal contour tool,and the evaluation indexes such as tool wear,chip morphology,surface quality and hole-axis deflection were analyzed during the machining process,and the results were compared with the cutting simulation to verify the correctness of the finite element model and the feasibility of the deep hole internal contour tool.