Strands: Concentric strands

In concentric strands, the individual wires are subject to an exact positioning around a core wire, which ensures an all-out uniform structure.

Applications

Extrusion: thin-gauge coating with high-grade isolation materials
7-end strands are particularly suited for data cables with high frequencies of transmission

Particular benefits for our customers

Uniform elongation of single wires
Low tolerances, even in single wires (even outperforming ASTM)

Manufacturing range

Materials: Cu-ETP1, Cu-OF1 and LEONI Histral® alloys
Bare, tin-plated, nickel-plated, silver-plated
Left-hand lay or right-hand lay
Variation: soft annealed
Single-wire diameter: ranging from Ø 0.05 mm to Ø 0.51 mm
Cross-section: ranging from 0.02 mm² to 630 mm²

Construction

The following strand constructions are possible:

concentric strand 7 end

concentric strand 19 end

concentric strand 37 end

7 ends = 1 + 6
19 ends = 1 + 6 + 12
37 ends = 1 + 6 + 12 + 18
etc.
More relevant details can be found in ASTM regulation B 354.

7-end and 19-end strands are the preferred choices for cables used in electronics. The precise positioning of the individual wires makes for a smooth and even surface as well as an unvarying diameter.

In concentric strands with more than 7 wires, 4 different lay-driven sub-categories can be found:

Construction unilay

Unilay concentric

same lay direction
same lay length
manufactured in one working step
nearly round construction (hexagonal)

Unidirectional concentric

same lay direction
different lay lengths for each working step
manufactured in two working steps
more round than unilay concentric

Direction of stranding

Construction true concentric

Equilay concentric (reversed lay stranding or SZ stranding)

different lay directions
same lay length
manufactured in two working steps
very round construction

Conventional concentric

different lay directions
different lay lengths for each working step
manufactured in two working steps
very round construction

Direction of stranding

Reversed lay direction / SZ stranding

S ➔ left hand lay

Z ➔ right hand lay

Strands with the same lay direction are generally called unilay.

Strand with opposing lay direction (SZ stranding) are called true concentric.

The roundness of a strand is driven by its lay length as well:

longer lay length = hexagonal

shorter lay length = more round

Moreover, there is a patented manufacturing process that allows for the production of strands featuring a highly compact and precise round structure: LEONI’s smooth bunches

Packaging

Reel sizes from 80 mm (1 kg) to 630 mm (400 kg), subject to diameter

Packaging information

Quality & Environment

Material Compliance

Quality & Environment

Sustainability

Other dimensions and materials

You need special designs and products for your applications?

Our R&D team is your partner for customised solutions.

Please contact!

Strands: Concentric strands

Applications

Particular benefits for our customers

Manufacturing range

Construction

The following strand constructions are possible:

In concentric strands with more than 7 wires, 4 different lay-driven sub-categories can be found:

Construction unilay

Unilay concentric

Unidirectional concentric

Direction of stranding

Construction true concentric

Equilay concentric (reversed lay stranding or SZ stranding)

Conventional concentric

Direction of stranding

Reversed lay direction / SZ stranding

longer lay length = hexagonal

shorter lay length = more round

Packaging

Quality & Environment

Other dimensions and materials

Our R&D team is your partner for customised solutions.

Related topics on our website

Materials

Producs

Product finder

Applications