Research On The Key Technology Of Digital Modification Of Meter-scale Ultra-precision Aerostatic Guideway

Existing highly versatile measurement systems are difficult to meet the measurement requirements of"large diameter,high precision"at the same time.The guide rail as a guiding element determines the travel and detection accuracy of the measuring system from the bottom.However,existing guide rails rarely achieve sub-micron manufacturing accuracy of meter-scale travel.When the slender rail is processed by traditional machining methods,the accuracy is limited by the measurement and cannot be improved.If the optical processing method is introduced,the edge effect is highly prone to increase the accuracy of the guide rail during the grinding and polishing process.At the same time,although there are many methods for detecting high-precision meter-scale rail position error,it is difficult to directly apply due to their respective limitations.Therefore,research on the processing and inspection of meter-scale high-precision guide rails is very important.In this paper,Corning7972glass is selected as the material of the meter-scale guide rail,and the high-precision digital shape modification and detection of the meter-scale guide rail is taken as the research object.The processing flow of the meter-scale guide rail is established,and the shape and position error separation detection processing scheme is proposed,the sub-micron manufacturing precision of the meter-scale guide rail is realized,and a set of measurement system is built.The research carried out in the thesis includes the following points:1.Proposing a set of digital shaping processing solutions to solve the sub-micron precision meter-scale guide rail manufacturing problem.In the lapping stage,the reciprocating translation parameters are improved.According to the stress simulation during lapping disc processing,a new lapping tool is designed to solve edge effect induced by modification.In the polishing stage,comparing three different processes,determining the polishing process of magnetorheological finishing technology(MRF)combined with polyurethane disk,reducing polishing cycle and improving surface accuracy;Finally,through the process of MRF reshaping and large disc smooth polishing to suppress edge effects and mid-high frequency effects on detection,and achieving sub-micron manufacturing accuracy of meter-scale rails.The PV values of the A and C planes of the rail(1000×240mm~2)are 0.548λ(1λ=632.8nm)and 0.540λ,and the PV values of the B and D planes(1000×160mm~2)are 0.432λand 0.442λrespectively.2.Establishing a high-precision detection method for the shape and position error separation of a meter-scale guide rail,which overcomes the detection problem in the process of high-precision meter-scale guide rail modification.According to the characteristics of air bearing,a new measuring platform moving mechanism is constructed,which solves the problem of interference splicing measurement of different sub-aperture movement measurement.The shape and position error separation and trimming strategy is proposed.The space coordinate data of the three-coordinate measurement is analyzed and transformed,and the MRF beveling method is used to finally complete the target of the verticality and parallelism of the meter-scale glass guide in 5μm.3.Based on the static characteristics analysis of the fixed hole and the actual machining,a set of guide rail structure design criteria is established.The scheme of combining water-cooled nesting cutter and diamond grinding rod is proposed,and the corresponding fixture and process details is designed.Achieving non-destructive mechanical punching with sub-micron precision of meter-scale rails;Completing the construction of a set of meter-level profile measuring system.Through the method of offline compensation,the single-dimensional straightness is 0.2μm/580mm.