Surface Topography Measurement of Mirror-Finished Surfaces Using Fringe-Patterned Illumination

Abstract

Mirror-finished surface products have a wide range of applications in different engineering industries, such as power generation, aerospace, semiconductors and optics. The surface topography of mirror-finished products is typically measured in a metrology laboratory, which is typically time consuming and cannot be integrated into the manufacturing process. To allow for in-situ product quality assurance and automatic tool change for manufacturing processes, a more accurate and responsive surface-measurement method is needed. For highly polished surfaces, a sub-micron surface fluctuation makes it possible to use light-scattering effects and image processing for surface texture analysis. A non-contact surface inspection system using a fringe-patterned illumination method is proposed in this paper. A predesigned pattern was projected onto the target surface, and its reflected image was captured by a camera. It was found that the surface parameters Sa and Sq, which are widely used to evaluate surface quality, are significantly correlated with luminous-intensity distribution. Another parameter, Str, which quantifies the uniformity of surface-texture directions due to polishing or grinding marks, was traditionally quantified after a complete-surface topographic measurement. In this research, a new approach is proposed to determine surface isotropy through a luminance-intensity distribution analysis. By rotating the test coupon, the variation of specular reflection showed correlation with the significance of surface-texture direction. The experimental results demonstrate that mirror-finished surfaces with a large deviation in luminance intensity across the pattern possess low Str values, which indicates low uniformity in surface texture.

Tribological behavior of UHMWPE in water lubrication: the effect of molding temperature

“…Laser confocal microscopy (VK-X2000, Keyence Ltd., Japan) was adopted to observe the surface topographies of UHMWPE samples before and after the wear tests. Meanwhile, the volume loss and the surface roughness ( S q ) after the wear tests were investigated (Fu et al , 2020; Paweł et al , 2020). Based on the volume loss, the wear rate was calculated according to equations (1).…”

Advanced Surface Enhancement

“…For example, surface topography measurement in mirror-finished products can be time-consuming and difficult to integrate into manufacturing processes. Study [6] reports the use of sub-micron surface fluctuation in combination with light-scattering effects and image processing to perform surface texture analysis. A non-contact surface inspection system using a fringe-patterned illumination method is proposed.…”

Experimental investigation of material properties of Al-Sic-fly ash composite

“…Tensile, flexural, hardness, and impact tests were performed and it was found that the hybrid composites had better properties than pure aluminium. Ceramic materials (CMCs), which are used in very high temperature settings, use a ceramic as the matrix and strengthen it with short fibres, or hairs along with silicon carbide and boron nitride [12]. The usage of waste products originating from agricultural operations (red clay, fly ash) and agro-based materials (rice husk ash, bamboo leaf ash, ground nut shell ash, among others) is increasingly improving aluminium matrix composite (AMC).…”