WCA March 2016

Measurement of a sloping position of the cable

Picture 6 shows a cable running in reference to a straight line. The cable, however, is running in an inclined position to the actual intended production line. In the illustration, the inclined position of the cable is exaggerated for a better understanding. A straight or inclined line, in this case a straight conductor, is defined by two points. By means of the first and second optical measuring device, the sloping positions of the cable will be identified and its influence on the measuring results will be determined and fully compensated.

Determination and compensation of a sag or bend of the cable

Sikora – Germany Bruchweide 2, 28307 Bremen, Germany Tel : +49 0421 4890 0060 Email : giersch@sikora.net Website : www.sikora.net The measuring system compensates automatically for a sloping position of the conductor in both horizontal as well as vertical direction, thus the measuring results are not influenced. The measuring system also records accurate measuring values, even when the cable is running through the gauge head with a sag or curved radius. Using the described measuring technology in extrusion lines ensures the production of high quality cables for a flawless assembly. At the same time, it contributes to process reliability and, consequently, cost effectiveness. Picture 7 illustrates a cable that shows a sag or bend. For a better understanding, the illustration of the bend of the cable is extremely exaggerated and, in practice, not likely. The bend of a conductor can be described by a circle, whose position and curve radius is defined by three points. With this information, the processor system is able to calculate the exact position of the cable in the inductive measuring plane and to fully compensate for the influence of angled position and/or bends. As shown in the picture, the measuring system is built in a way that the position of the cable is measured at four points, shown in the illustration as P1, P2, P3 and P4. Due to this, the measuring system is able to detect even irregular deformations of the conductor. Conclusion With the introduced technology it is possible to precisely measure the concentricity of a conductor in the insulation as well as the product parameters, outer diameter, ovality and wall thickness. The measuring technique records rotating or in one plane oscillating eccentricity values of the conductor in the form of a scatter plot. This scatter plot allows visualisation of the distribution of short-term variations of the eccentricity. Per the four-axes measurement as well as eight-point eccentricity measurement, a sloping position of the cable in the measuring plane can be recognised.

1 Inductive sensors 2 Two parallel, optical line sensors 3 Sag/bend of the cable 4 Type of production (direction) 5 Sloping position of the cable

❍ ❍ Picture 6 : Technique to determine a sloping position of the cable

Measuring points:

1 Inductive sensors 2 Two parallel, optical line sensors 3 Sag/bend of the cable 4 Type of production (direction) 5 Sloping position of the cable

❍ ❍ Picture 7 : Technique to determine a sag or a bend in the cable the result of a rotating (oscillating) conductor prior to the extruder crosshead. Picture 5 shows an ellipse type distribution of the scatter plot, which can happen, for example, when the conductor is oscillating or vibrating in one direction directly before entering the crosshead and which therefore additionally causes eccentricity variations. This permanent rotation eccentricity would also not be visible with a standard presentation of eccentricity (as shown in Picture 2 ).

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Wire & Cable ASIA – March/April 2016