More and more functionalities that have to be accommodated in less and less space and connected discreetly - this is one of the trends in device and system construction. Packing density is the key term. Compact cable and connection systems are in demand, which include components such as fiber optic cables or media hoses in addition to a large number of electrical connections for power and data. At the same time, the highly integrative systems should be quick and safe to install and ensure a reliable basic arrangement of the individual components. Traditionally, round, flat or ribbon cables - often with hybrid structures and/or in combination with energy guiding chains - are used here. In many applications, however, woven ribbon cables can be an economical and space-saving alternative as application-specific special cables.

In principle, the production of a woven ribbon cable corresponds to the production of a narrow strip of fabric in which various electrical cables, thin round cables, fiber optic cables or hoses run lengthwise like warp threads, while textile yarns create a fabric in the weaving machine. The intelligent use of the traditional manufacturing technology 'weaving' allows the production of individual ribbon cable constructions - without high commercial entry barriers. Unlike the production of a special flat cable, for example, which involves relatively high costs for injection molds and set-up times, weaving does not require any special tools or equipment. This means that smaller production batches for specific applications or prototypes can also be realized.

In contrast to laminated flat cables or round cables with an extruded outer sheath, the elements of the woven cable tape are processed without heat. This means that sensitive and less heat-resistant elements such as fiber optic cables, hoses, threads and ropes or even thin cables can be arranged as required. This provides a high degree of flexibility in the specific design or layout of the cable. The minimum bending radii of the woven elements remain unchanged in the woven composite. Fabric ribbon cables can be manufactured with an element diameter of up to 16 mm and a width of 180 mm. By additionally sewing or riveting individual fabric tapes, total widths of up to 800 mm can be achieved.

During the weaving process, only threads or yarns are added to the cables - neither foils as in laminating nor extruded insulating sleeves are required. The mass and volume of the finished fabric ribbon cable change only minimally - the textile-formed system cable does not have to carry around any extra pounds.

No problem changing bends

As there is no material connection between the neighboring elements in the textile composite, nor are elements enclosed by others, there is no thermal load. Fabric ribbon cables offer very good heat dissipation, so that it is also possible to transmit high currents or reduce the cross-sections while maintaining the same current strength. Last but not least, the high flexural fatigue strength speaks in favor of the textile-formed cable composite: thanks to the special layout, the individual adjacent elements can move freely against each other within the fabric. The fabric composite allows the production of elastic and flexible element band structures. The deformability over several axes is not critical. The use of twisted weaving yarns virtually eliminates abrasion even with very dynamic movements.

The choice of weaving yarn

The weaving process: While electrical cables, thin round cables or hoses run lengthwise like warp threads, textile yarns create a fabric at right angles to them.

© TKD cable

When fine-tuning the textile connecting cables, parameters such as the precise choice of weaving yarn or the individual adjustment of the fabric structure or the production process come into play. The weaving yarn is selected depending on the respective requirements or conditions of use. If, for example, particularly tensile warp yarns are used, this ensures optimum strain relief for the individual wires in the woven cable assembly. Electrically semi-conductive woven yarns guarantee the reliable dissipation of static electricity from the connecting elements, which is of interest for fast-moving cables in chip handlers, for example.

Warp threads inserted specifically into the tape ensure clearly defined distances between neighboring wires and thus support the interference immunity of the woven tape cable. The precise design of the production parameters also determines the practical performance of each individual fabric ribbon cable. One of the available adjustment screws is the tightening of the weft yarn running in the transverse direction: the tighter this design is, the more self-supporting the fabric ribbon cable can be. This makes it easy to eliminate the use of drag or energy guiding chains over distances of up to 2 m.

In elevator construction

In large concert halls, textile-based spiral cables score highly because they can be pulled out and put down smoothly and silently.

© TKD cable

Additional strain relief can be achieved by using a so-called 'backing weave' - a textile intermediate fabric. The carrier fabric itself can be used for installation or assembly. For example, TKD has developed fabric ribbon cables for elevator construction, in which the cable system is quickly and securely fixed in the elevator shaft floor by floor via specific recesses in the fabric mesh.

Another application is modern stage technology, where spiralized fabric ribbon cables are used. The textile cable systems are used here for vertical extension lengths of up to 9 m; classic spiral round cables are at a disadvantage in this case due to the combination of high weight and gravitational force. Finally, the weaving technology enables circular weaving in addition to straight tracks. This results in agile pull-out cables on a textile basis, which can be pulled out and laid down smoothly and practically silently.

Author:
Thomas Schmidt is Team Leader TKD 'Connectivity' at TKD Kabel in Pliezhausen.