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Comparison of Ultra-Precision Machined Surface Roughness Measurement Methods and Power Spectral Density Characterization

Author: ChenJianChao
Tutor: SunTao
School: Harbin Institute of Technology
Course: Mechanical Manufacturing and Automation
Keywords: Power spectral density Measuring instruments compared Surface roughness Sampling conditions
CLC: TG84
Type: Master's thesis
Year: 2009
Downloads: 203
Quote: 1
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Abstract

With scientific instruments, micro-electromechanical systems, photoelectric rapid development of the information technology requirements of various industrial sectors on the part surface quality is getting higher and higher, such as X-ray mirrors and laser gyro reflective substrate surface roughness in the sub-nanometer scale. This ultra-precision surface measurement technology and measurement theoretical system put forward higher requirements. This paper focuses on the measurement of ultra-precision machining surface related issues in the research, specific studies include the following aspects: overview of two-dimensional and three-dimensional surface morphology traditional evaluation method, discussed in the application of these traditional parameters limitations, and thus the introduction of the evaluation method of the power spectral density, and the definition of one-dimensional and two-dimensional power spectrum density estimation algorithm to carry out a detailed analysis. Given the inherent defects of the traditional estimation algorithm, the method of the the three improve power spectral density estimation quality, citing examples for each method, the results show that the three methods could overcome the defects of the original algorithm to improve the The power spectral density estimation accuracy. Summarizes the atomic force microscopy, the touch stylus profilometer and the principle of the white light interferometer and performance parameters, analyzes the error influence factors of these instruments, and on this basis, the application of these typical instrument including quartz glass, monocrystalline silicon and the crystallized glass including three samples measured by the surface morphology of these surface roughness values. The different measuring instruments having a different band width, so the measured roughness value and can not be directly compared. By computing the surface power spectral density of one-dimensional, and the total of the bands of the three instrument calculate the area under the curve of a power spectral density corresponding to each instrument, i.e., RMS value, to achieve a roughness of different instrument measured The value direct comparison. By comparison, the atomic force microscope is used to measure the best instrument for high-frequency surface structure. Found that further analysis of the measurement results, the measurement conditions (such as sampling interval, the scanning range) changes directly affect the surface roughness, and yet take into account the current standard file guide the selection of a reasonable sampling conditions, and thus this paper, based on spectral analysis determine a reasonable sampling conditions, and this method is verified by the measurement of two typical surface proved that this method is reasonable. In addition, the application of the atomic force microscope measurement of ultra-precision machining surface in different process conditions, and the application of power spectral density is characterized by a variety of surfaces. By comparative study found that the curve of the power spectral density, power spectral density is a powerful tool to guide the processing method selection and optimization of process parameters, it can quantitatively describe the distribution of the surface contour in the frequency band of space for a systematic analysis of the ultra-precision machining process on The quality of the surface provides a wealth of information.

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