Research On Optimization Design And Performance Of Ultra-precision Vertical Shafting System

The development of the manufacturing industry places more stringent requirements on precision and ultra-precision machining technologies.The ultra-precision five-axis machine tool is an important foundation for the realization of ultra-precision machining technology and plays a very important role in promoting the development of ultra-precision machining technology.The ultra-precision vertical axis system is an important part of the five-axis ultra-precision machine tool.The performance of the ultra-precision vertical axis directly determines the running accuracy and overall processing performance of the five-axis ultra-precision machine tool.Due to the influence of gravity,the high-precision positioning of the vertical axis during the movement will be greatly affected,and the high-precision positioning is mainly determined by the structural design parameters and static performance of the unloading cylinder and the hydraulic guide of the ultra-precision vertical movement system.Therefore,it is necessary to conduct in-depth research on the performance of key components such as the unloading cylinders and guideway of the ultra-precision vertical shaft system,thereby improving the high-precision positioning performance of the vertical shaft system and further improving the machining accuracy and reliability of the5-axis ultra-precision machine tools..The main structural parameters of the unloading cylinder and the hydrostatic guideway were studied by simulation analysis and experimental verification.The structural parameters of the unloading cylinder,the static performance of the aerostatic bearing and the structural parameters under different partial loads were respectively The static performance of hydrostatic guideway was studied.After comprehensive analysis of the influence rules,the design optimization parameters of each component of the ultra-precision vertical shaft system were proposed.Based on the dynamic mesh method,an unloading cylinder gas model and a piston movement model are established.FLUENT software was used to simulate and simulate the above model,and the effects of piston acceleration,inlet diameter and initial starting height on the change of the gas pressure in the cylinder were quantitatively analyzed,and its influence on the piston movement response was clarified.Then the dynamic response experiment of the unloading cylinder is used to verify the correctness of the simulation analysis results.After comprehensively analyzing the influence of each parameter on the dynamic response of the unloading cylinder piston,a corresponding optimization method is proposed for the design parameters and starting mode of the unloading cylinder.Using Gambit's software to model and mesh the gas film of aerostatic bearings,a progressive approach was used to refine the mesh at the orifice.Based on Reynolds equations,FLUENT software was used to analyze the finite element model.The effects of eccentricity,gas supply pressure,average film thickness,and orifice position on the static performance of the unloading cylinder were investigated..The simulation results of the static performance test of the gas hydrostatic bearing are verified.The optimal design parameters of the maximum bearing capacity and static stiffness are ensured without violating the principle of mechanical design,and the stable operation of the unloading system is finally achieved.A three-dimensional simulation model of the hydrostatic guideway oil film was established.The influence of the oil film under different deflection parameters and the influence of orifice diameter,average oil film thickness,eccentricity and oil supply pressure on the static performance was also considered.To find the maximum deflection parameters that guarantee performance requirements and the structural design parameters that are least affected by the deflection parameters,they are used to optimize the parameters of the ultra-precision vertical axis.