Centerview 8000 is the successor of the hundredfold proven classic Wandexe 203/803. The new measuring device is also used in many cable production lines worldwide.

Photos: Sikora

In the 70s, the first measuring device for the measurement of eccentricity, the Wandexe 203, was offered with pointer instruments. Monitors did not exist at that time.

In the 90s – before the development of the X-ray measuring system X-Ray 8000 – high voltage cables were measured manually and offline under the microscope.

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In the early 70s, the eccentricity measuring device Wandexe 203 for insulating lines provided the basis for today’s inline measuring and control technology for wires and cables. With the newly developed device by Harald Sikora, it was possible for the first time to measure the eccentricity as well as the diameter of wire and cables during the production. This was a pioneering achievement because in the 50s and 60s, micrometer screws or calipers were still being used for quality control. Using these tools, cables were checked at the beginning and at the end of the reel. At this time there were no measuring values available for control. Soon followed a system for measuring the cable position in steam CV-lines1; the so called sag measurement. With this measurement it was possible to define the vertical position of the conductor and to control it to the middle of the CV-tube. Before, predominantly measuring wheels were used that ran on the cable in the CV-tube. The consequence of this method was often damage to the product’s surface.

During the mid 70s Sikora developed diameter measuring devices with line sensors in Bremen, Germany. The functional principle resembles today’s known image sensors in digital cameras. The greatest difference was the lower number of pixels. At that time it had been 512. Today image sensors with over 14 mega pixels are offered and also used in Sikora devices, for example in the length measuring system, Length 6000. During the 70s this technology was relatively unknown, but it formed the basis for the reliable, repeatable measurement of wire and cable during the production. Sikora was the first company to produce and internationally sell diameter devices for CV-lines.
In the early 90s the market for high voltage cables expanded. In addition to the outer diameter, manufacturers aimed at determining the 3 insulation wall thicknesses of the cable. Sikora responded to the demand with the development of an X-ray based measuring device. On the one hand, it had to be integrated into the telescopic tube of the CV-line in order to assure that immediately after starting the line, measuring values were displayed for centering and control. On the other hand, the device had to be suitable for installation into steam as well as nitrogen lines. The result was the development of the X-Ray 8000 for measuring the eccentricity, wall thickness and the diameter. There are more than 800 X-Ray measuring systems at customer locations and this is the industry standard worldwide.
In the mid 90s the portfolio was complemented by systems for insulating lines, in which communication, automotive and installation cables are produced. The Inline-2000-series comprised diameter, wall thickness and eccentricity measuring devices such as the Centerview, successor of the Wandexe 203 as well as lump detectors, high-voltage testers and capacitance measuring devices. The engineers in Bremen integrated solutions that did not exist in such devices previously. For instance, in the diameter and capacitance measuring devices an FFT-analysis and prediction of the structural return loss (SRL) was included. Sikora was the first supplier of devices which already had Profibus integrated.

Until then cable manufacturers used measuring technology in particular for quality assurance of the production. However, with the turn of the century material saving in addition became an important criterion. Measuring devices for jacketing lines were increasingly demanded, which could measure and control wall thickness. Until then, the diameter difference measurement was calculated by taking cable measurements before and after the extruder. From the difference of both the wall thickness was defined. Indeed, in this way the insulation wall thickness could determined, but the principle did not provide information about the concentric distribution. As the wall thickness measurement via X-ray with the X-Ray 8000 had been proven for more than 10 years, Sikora used this technology also for measuring the concentricity of jacketing lines. The new system X-Ray 2000 combined all advantages that were already successfully used in other measuring devices such as diameter measurement with CCD-lines and the X-Ray in CV-lines. Today, modern insulating and jacketing lines are equipped with this technology. They are suitable for the measurement of both round and sector cables, as well as high frequency cables with foamed insulation.
Since 1993 Sikora AG has been certified according to the quality standard ISO 9001. The certification proves to be successful because with regard to the continuous improvement of the product quality, the MTBF (Mean Time Between Failure) of many devices has increased up to more than 14 years. At the headquarters in Bremen there is a research and development team of 29 employees working at the systematic further development of the measuring technology and new products. With these innovations the company aims at maintaining and strengthening its position in the market in the upcoming years. In 2010 Sikora launched numerous new products such as the Length 6000 – a non-contact system for measuring the length of cables. The Preheater 6000 – a conductor preheating system – helps to achieve a good adhesion of the insulation on the conductor during the production of telephone and data cables, as well as the manufacture of automotive cables. Additionally, the new Ultratemp 6000, which measures the temperature of the polymer melt in the flow channel during the production of high-voltage cables.
1) CV = Continuous Vulcanization
A CV-line is an extrusion line where among others middle, high and extra high voltage cables with triple layer insulation are produced. In a CV-tube that can be up to 200 meters long, and directly follows the cross head, the cross linking of the polyethylene material takes place respectively rubber insulated cable are vulcanized under high temperature and high pressure. Doing so allows the insulation material gets its mechanical temperature stability.