Concurrent measurement method of spindle radial, axial and angular motions using concentric circle grating and phase modulation interferometers

Abstract

This paper describes a concurrent measurement of spindle radial, axial and angular motions using concentric circle grating and phase modulation interferometers. In the measurement, the concentric circle grating with fine pitch is installed on top of the spindle of interest. The grating is a reference artifact in the method. Three optical sensors are fixed over the concentric circle grating, and observe the proper positions of the grating. The optical sensor consists of a frequency modulated laser diode as a light source, and two interferometers. One interferometer in the sensor observes an interference fringe between reflected light form a fixed mirror and 0-th order diffraction light from the grating to measure the axial motion. Another interferometer in the sensor observes an interference fringe between ±2nd order diffraction lights from the grating to measure the radial motion. Using three optical sensors, three axial displacements and three radial displacements of the proper observed position of the grating can be measured. From these six measured displacements, radial, axial and angular motions of the spindle can be determined concurrently. In the paper, a measurement instrument, a fringe interpolation technique by sinusoidal phase modulation and experimental results are discussed.

A novel representation method of non-ideal surface morphologies and its application in shaft-hole sealing simulation analysis

“…Zhang et al studied the typical manufacturing errors, such as errors caused by spindle rotation, fixture distortion, misalignment of spindles and work centers, workpiece deflection et al The effects of these errors on manufactured surfaces are also investigated 20 . Muhummad et al described a concurrent measurement of radial, axial and angular motions of spindle using concentric circle grating and phase modulation interferometers in order to depict the deviation of the manufactured surface from the nominal surface 23 . Chien expanded the approximated harmonic model by adding the knowledge of machining process 24 .…”

A simple optical system for miniature spindle runout monitoring

“…Spindle runout is a rotation inaccuracy which occurs when the cutting tool is no longer aligned with the rotational axis, and can be classified as axial runout and radial runout. The former occurs when the cutting tool is rotating at an angle to the axis [1][2][3][4][5][6], and the latter occurs when the cutting tool is rotating off center to the rotational axis. Spindle runout in computer numerical control (CNC) machine tools can decrease tool life and leads to the machining of defective parts, for example, in drilling applications, spindle runout can result in a bore diameter that is actually larger than the drill's nominal diameter [6][7][8].…”

“…Capacitive sensors (CS) or eddy current sensors (ECS) are particularly well suited for measuring the performance of high speed precision spindles and other rotating shafts [6,8]. Since CS and ECS provide high measurement bandwidth and fast response, they are capable of gathering data even as the spindle or shaft sweeps through its entire speed range.…”

Large-range displacement measurement using sinusoidal phase-modulating laser diode interferometer

“…The sinusoidal phase-modulating laser diode (SPM-LD) interferometer has been used for vibration sensing and displacement measurement because of unique features such as simplicity and good expansibility [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] . However, the measurement range of this interferometer is limited to a few micrometers because an important parameter, the effective SPM depth, is considered to be a constant in conventional signal processing [1][2][3] .…”

“…Moreover, as the real value of the effective SPM depth moves away from the fixed one used in the traditional method, the errors could be greater. So, these errors cannot be eliminated perfectly by common nonlinear error correction methods, such as the Lissajous diagram [12][13][14] and the ellipse-fitting method [15] . A novel method for obtaining the dynamic value of m, which is denoted as m r ðtÞ, is proposed.…”