Detection of color faults on cable insulation

摘要

The difference of colors between two cables can be safety relevant. For controlling purposes, often visual inspection with color cards is used to check the acceptance limit of the specified colors. Visual assessments are subject to subjective impressions arising from factors such as illumination, angle of vision and the color sensitivity of the observer, whereas an automatic system gets objective, reproducible and comparable results. This paper introduces some color basics and depicts important differences in color measurements between cable applications and the paint industry: A new developed color checking system has been shown to be effective for cable production lines as well as for offline testing. Various tests to define the limitations on geometry and movement (speed, turning) are described for single colored and stripe coded cables. The measurement techniques, best-fit-scan' and, tolerance scan' will be explained. The result is a quasi continuous inline color control similar to diameter or spark testing and a simple offline quality check independent from the human eye color perception.