Evaluation of the surface deflections in pressed automobile panels by an optical reflection method

The surface deflections in an automobile panel pressed by a punch have irregular distributions of configuration, inclined angles and curvature along a line. Here, a simple quantitative and convenient measurement method is proposed to measure and evaluate the surface deflections of sheet metal and the associated location directly after press forming by using an image-sensing camera system. First, the mathematical equations of optical geometry are formulated, and the implementation of the measuring procedure is given for quantitative measurement. Second, its effectiveness is verified and discussed in relation to the results of experiments. The merit of this method is its ability to measure the reflected point of light along a line on a mirror-like surface of sheet metal directly, where the surface deflections can be evaluated by comparison with the levels recorded previously.