In order to analyze the performance of aerostatic guidways,the stiffness calculation equation of the aerostatic guideway with two-row orifice has been derived by gas lubrication theory. For the complex structure of the motion guideway and unloading guideway,the frequency of the whole slides in machining direction with gas thickness has been derived. Wavelet transform as a means to process the measured signal of workpiece surface, the frequency characteristics of gas fluctuation of aerostatic guideways has been extracted out from the measured signal,and the errors of the guideway system have been identified according to the power spectral density (PSD) ,and this provide a basis for the identification of machine tool error.
Single point diamond fly cutting is widely used in the manufacture of large-aperture ultra-precision optical elements. However,some micro waviness( amplitude about 30 nm,wavelength about 15 mm) along the cutting direction which will decrease the quality of the optical elements can always be found in the processed surface,and the axial vibration of the spindle caused by the cut-in process is speculated as the immediate cause of this waviness. In this paper,the analytical method of dynamic mesh is applied for simulating the dynamic behavior of the vertical spindle. The consequence is then exerted to the fly cutter and the processed surface profile is simulated. The wavelength of the simulation result coincides well with the experimental result which proves the importance of the cut-in process during the single point diamond fly cutting.
