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Proceedings Paper

Optical Methods To Evaluate The Surface Waviness Of SMC Panels
Author(s): Raghunath P. Khetan
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Paper Abstract

Two methods are presented in this study to optically assess the surface waviness of painted SMC (Sheet Molding Compound) panels. In both methods, a coarse grating is reflected by the panel surface and the resulting image is recorded for further evaluation. In the first method, the reflected grating image is superimposed on a reference grating to create a moire fringe pattern. A small rotational mismatch between the two gratings amplifies the grating distortions. The panel surface waviness is qualitatively assessed by visually evaluating the overall waviness of the moire fringes. In the second method, the reflected grating image is evaluated directly for the spacing variations, which are related to the variations in the panel surface waviness. A statistical parameter, called the Waviness Index, is proposed to provide an average measure of these variations and is shown to have a good correlation with overall surface waviness.

Paper Details

Date Published: 17 February 1987
PDF: 9 pages
Proc. SPIE 0814, Photomechanics and Speckle Metrology, (17 February 1987); doi: 10.1117/12.941697
Show Author Affiliations
Raghunath P. Khetan, General Motors Research Laboratories (United States)


Published in SPIE Proceedings Vol. 0814:
Photomechanics and Speckle Metrology
Fu-Pen Chiang, Editor(s)

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