Aerostatic Spindle Error Measurement Technology Research

Machine tool is the manufacture platform and its spindle's rotation error is an important factor which influences its machining precision.How to improve the spindle's rotation accuracy is a key technology in the process of machine tool's designing,manufacturing and servicing,so that the measurement of spindle's rotation error becomes an important technic problem as well as the improvement of measuring precision.Gas spindle is the representation of ultra-precise spindle,so it is deserved that we do research on its high precision and dynamic measuring technology.On basis of referring to home relative literature,this paper advanced three error hefts(radial rotation error,axial rotation error,angle swaying error)to confirm spindle axes' error model of its space position.This model provided an efficient method to describe the system of the spindle rotation error and established a good foundation on measuring technology.Contraposing the problem of test stick method the GB recommended doesn't have high precision when used,this paper targets to improve measuring precision and studied on measuring method based on standard ball(called "standard ball method"for short) generally. Using standard ball as the measuring benchmark,we don't need object which has good benchmark and testing stick which is very hard to find the right place when installed.For the purpose of obtaining better measuring precision of rotation error,this paper used error separation technology to debase the eccentricity and the bad influence of the standard ball's roundess.It is proved that wiping off one concordant wave can debase the influence of eccentricity to measuring precision through emulating experiment,meanwhile,emulated the separation accuracy of reversal-method,three-point method,several-step method and the result indicated that the reversal-method has the best separation precision.The two-sensor method this paper advanced is an error separation method based on reversal-method.This method has simple arithmetic like reversal-method and also can debase the space error of reversal installing sensor,so that it can meet the requirement of high precision measurement.Based on above theory research established system for experiment,designed simple and effect adjusting eccentricity machine and a suit of software system including separation arithmetic based on Labwindows/CVI,accomplished one sensor measuring ultra-precise radial,axial rotation error experiment and two sensors measuring dynamic radial rotation error experiment:static rotation radial error is below 0.1μm,the roundess of the chinaware ball is 0.06μm,repeatable precision is 0.01μm;dynamic radial rotation error is 0.5μm,repeatable precision is 0.12μm,the roundess of the steel ball is 0.35μm,repeatable precision is 0.05μm;the axial rotational error is lower than 0.2μm The static result is reasonable,contrasting to roundness measuring instrument,but dynamic result has some windage because of sensor's capability.