EuroWire January 2018

Technology News

Advantages of the CCD line sensors of the Laser series 2000/6000

AN increasing quality awareness in many areas of daily life and especially in the field of industrial goods has been observed for some years. Manufacturers of wires and cables have also been investing intensively in measuring and control technology as well as inline control over the few last years. At the same time, amongst others, the diameter and ovality of products play a crucial role. These cable parameters can be measured in the production line by different techniques. Until now, three different methods for measuring the diameter have been established on the market: laser scanning, conventional shadow projection, and the diffraction-based method (laser shadow projection). Laser scanner measuring devices work with a rotating mirror or a rotating disk striking a laser beam across the measuring field. Thus, two lenses are used to adjust the laser beam almost parallel across the measuring field and onto a light sensor. The product diameter is calculated by comparing the time during which the laser beam is shadowed by the product with the time the laser beam needs to pass the whole measuring field. Conclusion: The measuring frequency depends on the rotation speed and the surface finish of the mirror. An averaging from several measurements is often necessary to achieve a high accuracy. The digital measuring method with CCD line sensors requires no moving components. Therefore, accuracy, repeatability and measuring rate are higher. One can distinguish between the classic shadow projection and the diffraction-based method. The conventional shadow projection, like the laser scanning method, uses two lenses, which are installed in front of and behind the product. These lenses adjust the laser beam onto a CCD line, on which the darkened diodes are counted in order to determine the diameter by means of the shadow image. Conclusion: Using optical lenses is very cost-intensive. As a result, assembly, alignment and calibration requirements have a negative impact on profits and amortisation. Regarding the diffraction-based method – the measuring principle of Sikora’s Laser series 2000 and 6000 – the high-resolution laser beam directly illuminates the CCD line. According to the theory of diffraction, the left and right geometrical-optics shadow edges are calculated from the diffraction fringe information. Thus, the product diameter can be determined by their distance from each other. Gauge heads with the CCD line sensor technology measure the diameter of transparent as well as opaque products in two or three planes. In addition, they work precisely, independent of the materials used. Conclusion: The diffraction-based method works with an extremely high measuring rate that is only limited by the frequency of the CCD line sensors. This allows several thousand measurements per axis per second for product diameters from 0.05 to 500 mm. Furthermore, the gauge heads of the Laser series 6000 guarantee reliable detection of lumps and neckdowns on the product surface. Upon request, the lumps and neckdowns can either be

visualised directly on the display at the gauge head or displayed, documented and analysed by Sikora’s display and control devices. Sikora AG – Germany Website : www.sikora.net ▲ ▲ Diffraction analysis of the CCD line sensor signal. Measurement by means of two measuring axes

Wire green cleaning for plating quality

The PWC system performs wire cleaning and polishing in-line with wire drawing machine. Exceptional cleanliness obtained permits wire direct brass coating, copper coating, galvanising and wire cleaning prior to heat treatment and coating applications including patenting, annealing, painting, plastic coating, etc. The system incorporates new technology that enables normal cold plant water to be converted into a unique cleaning medium generating high pressure wetting/contaminants extreme pressure extrusion/hydrodynamic cavitations displacement and contaminants flush out, used to clean drawn wire at high speed in a completely green application, providing a glossy wire finish in plating quality. The PWC system effectively removes lubricant residue from the base material and is particularly recommended for cleaning applications with wires drawn upon severe conditions resulting in increased heat and burned lubricant tightly bound to the wire surface and embedded in micro-cavities. For decorative mirror reflective wire applications, the system can be used with a light emulsion diluted at three to five per cent concentration. The PWC unit is compact and can be easily installed on the finishing/last block of a wire drawing machine.

Decalub – France

Website : www.decalub.com

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January 2018