Cable Diameter Gauge (Measuring), Non-Contact

Since the 1980s, non-contact diameter gauges have become increasingly important, with a form of light (typically lasers) the key. This technology can be used to automatically control cable size. There are different types of systems that use lasers. A laser-scanning system typically uses a laser beam directed at an inspection area that strikes a rotating multi-sided mirror that creates from 80 to 200 scans per second. Those scans are received by a photoelectric cell based on the relative time intervals of light and shadow as the light beam is interrupted periodically by the cable. It has a frequency of approximately 6 Hz. A laser-diffraction analysis system, a more sophisticated optical technology, can measure cable 500 times per second, with the results analyzed by laser diffraction analysis. Another non-contact system uses the same CCD technology used in video cameras. The “camera” monitors the cable as it passes by. The control system measures the number of pixels that are occupied by the cable image and translates it into a dimension. All three systems can employ closed-loop control of the extrusion process.