Calmont Wire & Cable BLOG

A super flexible wire design requires two things, a flexible insulation material and the right conductor stranding. Even with the most flexible wire insulation, the flexibility of the wire will depend on the conductor stranding. Conductor construction is key in achieving a noodle like flexible wire. There are two things to look at when choosing the right conductor:

1. Number of strands. Conductors are made of many fine strands which are cabled together to meet the required gauge size. Conductor stranding is available from one strand (solid) to hundreds depending on the gauge size. The higher the strand count the more flexible  and resistant to flexing fatigue the wire will be. For example a 24AWG wire, the stranding options are from 1 strand (solid) all the way to 105 strands. That’s quite a range.

2. Conductor construction. How these fine strands are put together is as important as the strand count. The most common configuration is concentric. Concentric conductor may be defined as: a central wire (strand) surrounded by one or more layers of helically laid wires in a geometric pattern. Rope stranding has the advantage of increasing flexibility by using a larger number of finer strands while maintaining a tighter diameter tolerance than a simple bunched construction. to read more in depth about conductor construction read our conductor stranding page on this blog.

Flexing vs. Flexibility

To some flexibility means to withstand repetitive flexing, while to others it means how much the wire will bend and rigidity. For both types of applications a high stranded conductor is recommended. For repetitive flexing one should consider using an alloy material for higher strength and flex cycles. For noodle like flexibility a standard copper conductor is fine.

Flexible cables

Flexible cables also use high strand conductors, but there are more factors involved controlling the flexibility; Such as, Shielding, outer jacket material, cable lay construction and type of conductors  just to name a few.

It’s always best to discuss your flexibility needs and the conductors available with a wire and cable manufacturer, especially one that works with high strand count conductors. Off the shelf (commodity) wire manufacturers usually work with solid, 7 and 19 strand conductors which are less flexible than the high strand conductors. For more information or to discuss your requirements, contact Calmont today.

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The aerospace industry has applications which can be very critical of weight; Such as, missiles, rockets and satellites. When looking for ways to cut down equipment, payload, or satellite weight, the cable can be the last thing considered. One way to accomplish weight reduction in aerospace cables is to use metal clad aramid fibers for the shield and braid material instead of the standard copper. Aracon® is one such material which provides exceptional EMI shielding, strength and flexibility. Typically Aracon® fibers can reduce weight 60% in the weight of the braid over copper braids. Aracon® is combined with DuPont Kevlar® to provide high tensile strength and excellent conductivity. The large number of fine threads and the tendency of yarn to flatten and spread give this material more shielding coverage than copper. In the first photo you can see the amount of fibers on the end of the braid.

Benefits for switching from copper braid to Aracon include:

• Overall cable weight reduction
• Added flexibility
• Increased strength
• Withstands repetitive flexing
• Improved EMI shield coverage

 

Aracon® fibers are manufactured by only one company Micro-coax Inc. The Aracon® braid can be purchased either with the braid only (sock) or having the braid manufactured onto cables by cable manufacturers such as Calmont Wire & Cable. Calmont has had great success manufacturing cables using Aracon® for the space and military related applications.

The cost of using this type of material is considerably more expensive than the standard copper braid. The cost savings for applications such as satellites where weight savings equate to rocket fuel cost, definitely makes it a value. An example of cost savings is the  SBIRS (spacebased infrared system) project. The cable harness for the SBIRS antenna weighs about 3.5 pounds (1.6 kilogram) less than equivalent cables using metal braid and alternative insulation and jacket materials.

‘With payload weight valued at $90,000 per pound at the time, the lightweight cable saves the SBIRS program $95,000 per satellite after accounting for the additional cost of the Aracon® braid compared with metal” Says Don Dodge VP research & Development for Calmont Wire & Cable.

Watch the video about Aracon®

Depending on your shielding requirements, Aracon® is available with several metallic coatings, thickness and fiber sizes to meet your resistance needs. Consult your cable manufacturer or Micro-Coax for options available to you.

If you would like to learn more about EMI shielding, Aracon® or similar materials contact Calmont today. Your comments are welcome and if you find this article useful, please share it.

 

 ARACON® is a registered trademark of Micro-Coax, Inc.
KEVLAR® is a registered trademark of E.I. du Pont de Nemours and Company