TECHNOLOGY NEWS:
Production line for corrugated micro-tubes
Corrugated micro-tubes (CMT) are produced from aluminium, stainless steel or copper strips with thickness typically ranging from 0.06 up to 0.2mm. These tubes can be used as a cable sheath or as flexible pipes. In the cable industry, they are used as an outer conductor of RF-cables (copper) or as a sheath for polymer optical fibre cables (aluminium). Due to their thermal and electrical conductivity, they offer heat protection and act as an electrical conductor for the power supply of electrical devices. Their mechanical properties offer protection against hazardous environments. Nexans Deutschland Industries GmbH, Germany, provides its UNIWEMA® forming and welding line, which forms and welds a metal strip into a tube. Depending on the tube’s future purpose, the tube is corrugated, reduced in diameter, elongated or simply calibrated afterwards. These production lines are applied in many different areas of cable and tube industry. The UNIWEMA® technology is used to produce, for example, coaxial RF-cables (3 to 300mm Ø, corrugated or smooth), high and medium-voltage cables (50 to 150mm Ø), telecommunication cables or FIST (fibre in steel tube) products such as OPGW.
A special UNIWEMA® line for the production of CMT-products, which can produce corrugated tubes from 2 to 6mm Ø, has recently been developed by Nexans. In this machine the metal strip is drawn-off from a strip pay-off. All weldable materials, with mechanical properties that allow the forming of a tube shape, can be used for this process. The strip edges are trimmed by rotary knives. The tube is formed by means of a forming tool, the strip edges in butt position. Then, this tube is butt welded via laser. Because of its high efficiency, a CO2 laser is used for welding ferrous materials. Materials with a low absorption coefficient (such as aluminium and copper) are welded with a solid state laser. A specially designed split-clamp caterpillar capstan is the only means of transporting the tube through the production line. After the tube is formed and welded, it is gripped and transported by the clamps. At the exit side of the split-clamp caterpillar capstan the clamps open and, by the chain, on which the clamps are mounted, move back to the entrance side. By the combination of the forming tool with this continuous split clamp caterpillar capstan with its reliable and stable tractive force any torsion of the tube under the welding point will be reliably avoided. Leaving the split-clamp caterpillar, the tube enters the corrugator in which it receives its helical corrugation. Inner diameter and pitch can be adjusted within certain type-specific limits. Due to the corrugation, both the transverse stability as well as the flexibility of the tubes and sheaths are increased.
Up to now, this technology is successfully applied for copper, aluminium and stainless steel tubes. The wall thickness range is 0.06 to 0.2mm, the thinner walls of corrugated tubes are preferably used for stainless steel products. Due to the reliability of this production process, cable of any length can be produced. In FIST-production cable, lengths of up to 25km without any stop or welding fault are common practice.
Company: |
Nexans Deutschland Industries GmbH & Co. KG |
Country: |
Germany |
Fax: |
+49 511 676-3777 |
Email: |
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Website: |