7 basic rules for successful cable guidance
The world of cables is intricate and complex, similar to the design of the cables themselves. So, understanding the reasons behind the technology is important. With the igus® chainflex® cables, we have a set of 7 rules for a successful cable guidance system which ensures that the cables are long lasting for your application.
1. Strain-relieving centre element
A strain-relieving centre element is clear space created in the centre of a cable. The size of this cavity will depend upon the number of cores and their cross-sectional area. This centre should be filled, as far as possible, with a proper core element (not with fillers or dummy cores consisting of waste material, which is frequently the case). These measures will then efficiently protect the braided structure and prevent the cores from wandering into the middle of the cable.
2. Strands optimised for movement
Several test series have helped to determine which combination of wire diameter, pitch length and direction provide the optimal bending resistance in cables designed for movement. Although there are some very flexible cables that can be made using very thin individual wires, these tend to find themselves subject to extreme deformations or kinks. With the igus® chainflex® cables, we test, research, and learn about the best combination for our flexible cables to ensure no kinking and the longest service life for our cable guidance systems.
3. Core insulation
The core insulation materials must be made so that they do not stick to one another within the cable. Furthermore, the insulation is required to support the individual wire strands of the conductor. With igus® chainflex® cables, only the highest-quality, high-pressure-extruded PVC or TPE materials that have proved their tested reliability in millions of core kilometres are then used in e-chain® applications.
Compared to standard cables, chainflex® cables are stranded very differently. In standard cables, the cores are stranded with large pitch lengths which in theory means this will prevent cores from becoming loose in production, however, it isn’t as strong as the stranding method of chainflex® cables.
chainflex® cables are not only stranded with a shorter pitch length, meaning they are stronger, but we also bundle the cores together. These bundles absorb the push and pull forces which occur in the movement of the cables, further preventing the corkscrew effect within cable guidance.
5. Inner jacket
In chainflex® cables, a gusset-filled, extruded inner jacket is used instead of low-cost non-woven fabric, filler or tracer. This ensures that the stranded structure is efficiently held in the longitudinal direction. This also means the stranded structure cannot fall apart or move around. Hence, the inner jacket serves as solid foundation for the shield.
Each electrical cable can, in theory, suffer electronic magnetic interferences due to the coupling effect. To ensure electromagnetic compatibility (EMC), a cable must be electrically shielded. The shield should generally have a taut structure. Loose open braiding or wrapped stranding reduces the EMC protection considerably and can fail very quickly due to shield wire breakage. This protective shielding is expressed by the indication of the “optical coverage” of the shield. This is the area that is optically covered by the shield. If the shield is braided or surrounded with wires, this has the advantage that, in contrast to the foil, the shield is not affected by movement.
For cable guidance in linear motion, it has been found that a braided shield with high coverage and optimal braid angle is the best solution.
7. Outer jacket
An external jacket made of PVC, PUR or TPE can meet a wide range of specifications: from UV resistance, through low-temperature flexibility and oil resistance, to cost effectiveness. However, they should all have the following in common: a jacket material should be highly resistant to abrasion without sticking and highly flexible while still being supportive. In addition, all external jackets should be extruded at high pressure (gusset-filling).
There is a collection of blogs recently published that go into more depth on both control cables and motor servo cables and how they are used in cable guidance. You can read them here: Control https://blog.igus.co.uk/what-is-a-control-cable/ and Motor Servo https://blog.igus.co.uk/what-is-a-hybrid-servo-cable/
If you have a requirement for chainflex® cable guidance systems, please contact us.