Film Appearance performance test

The bridge pattern is the corrugation on the surface of the coating similar to the bridge skin. It has a lot to do with the surface roughness of the substrate, the leveling of the paint and the construction process. In the past, the severity of the orange peel was determined by visually observing the size of the bridge pattern. The bridge skin instrument performs the scanning test of the surface corrugation (see Figure 8-8)

The laser is irradiated to the measured surface at an angle of 60°, and the reflected light is measured through slit filtering in the direction of the other side at an angle of 60°. When measuring, the instrument moves a distance of 10cm to the west of the measured table, and scans by reflecting 1250 times of laser irradiation. When the laser shines on the peak or valley, it receives the strongest reflected light; when it shines on the wave slope, the reflected light is the smallest, and the obtained light shape curve corresponds to the optical profile of the surface corrugation observed by the naked eye. The frequency of the curve is twice the frequency of the mechanical wheel hall curve measured by the roughness meter. The corrugations with a length of more than 0.6mm are counted as long waves, and the corrugations below 0.5mm are counted as short waves. The fewer the number of long and short corrugations within a certain distance, the lighter the bridge skin. Short corrugations are mainly affected by the roughness of the substrate, while long corrugations are mainly caused by the construction process. The degree of bridge skin between the horizontal plane and the vertical plane, plane and complex plane is often very different, and the test should be done in different areas. Select several points. And the control indicators are also different. For example, a large automobile factory stipulates that the long-wave <4 and short-wave <20 in the plane area; the long-wave <15 and short-wave <25 in the vertical area.