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 The UNIWEMA® process is designed to form a metal strip to a welded smooth or corrugated cable sheath.
In this process, a metal strip is introduced into the machine and, in a single operation, the strip edges are trimmed and formed around a cable core. Then the opposing strip edges are welded. A capstan located downstream from the welding station pulls the sheathed cable through the machine and, if added flexibility is desired, transports it to the corrugator.
The perfect coordination of the forming and welding operations with the split clamp caterpillar capstan is a precondition for obtaining a uniform welded seam, thus ensuring optimum product quality.
The design and the material of the several stages of the tube forming station are dictated by the characteristics of the metal strip, its wall thickness and the diameter of the welded tube. A wide range of forming tools for the most diverse applications is available. Specially optimized tool sets for new products can be developed and supplied. A precondition for obtaining a good welded seam is the accurate positioning of the strip edges at the welding point. They must exactly meet each other with a minimum gap.
The standard UNIWEMA® is equipped with a single electrode. In applications where the maximum allowable welding current with one electrode is insufficient for the welding of thicker strips or if higher speeds are desired the UNIWEMA® can also be operated with a 3-electrode welding torch system, Polyarc welder.
Due to the performance of the UNIWEMA® application and necessity to use different metal materials the use of different Laser welding methods is possible. Especially for thin wall thicknesses and small tube diameters the Laser welding method is the most suitable. Advantages of the Laser system are a significant reduction of the heat influenced zone and insensitivity to remaining dirt or oxide deposits on the strip.
Depending on the material to be welded (type and wall thickness) either the CO2 Laser with RF excitation, Nd:YAG Laser (Yttrium-Aluminium-Garnet, doped with neodymium) or Diod Laser can be employed.
The corrugater.has a freely rotating corrugating ring inside the corrugating head which can be adjusted in radial direction and in its angle imparts corrugations to the tube whereby pitch and corrugation depth can be set. In cable sheaths, the corrugated tube grips the cable core tightly. Through choice of a suitable corrugating tool helical or annular corrugations can be produced.
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