A highly abrasion- and notch-resistant cable jacket is essential for applications involving high mechanical loads. In order to meet this requirement, PUR is often used in the production of special cables.

Cadmium copper alloy is an ideal material for applications involving a high degree of alternating bending stress and small bending radii. Alloying additions improve the strength of pure copper and ensure that litz wires made from this material are more mechanically stable. Alloys stand out for their especially high tensile and fracture strength:

Property	Alloy
Electrical conductivity	Very good approx. 90% of the electrical conductivity of copper
Tensile strength	480 N/mm² with 15-20% elongation
For alternating bending stress	Optimal
Solderability	Very good
Temperature range bare tin-plated silver-plated	+130°C

Today’s state-of-the-art automated equipment, robot technology and transport systems all require cables that can withstand extremely high mechanical loads, such as those found in robots with handling systems that combine stretching and rotating movements. These movements place the cable under enormous alternating bending stress in conjunction with small bending radii. In such cases, selecting the right materials, such as alloy litz wire, is critical to ensure that the cable has a long service life.

See also alternating bending stress | alternating bending performance

Alternating bending performance refers to the durability of the cable when it is permanently bent in alternating directions. For example, the S-shaped curve of a cable is a form of alternating bending.

 

See also alternating bending stress | alternating bending cycles

A wide variety of materials can be used for banding, depending on the purpose of the cable. Banding fulfils several key functions within the cable assembly.

It uses colour coding to identify individual cores, core groups and stranded components.

 

For flexible cables in particular, avoiding friction or adhesion between the individual elements inside the cable is crucial. Banding prevents breakage in the inner cores by providing a “sliding layer” between individual elements of the cable. Banding also serves as a protective layer, protecting against flame or water.

 

HRADIL uses the following materials for banding:

 

• PTFE film
• Non-woven fabrics
• Polyester mesh tape for banding multi-core cables and increasing dynamic short-circuit resistance
• Quartz and silica glass banding for protecting electric cables against flame and heat of up to 1100°C

Bending stress (or alternating bending stress) refers to the stretching of the outside and the buckling of the inside of the cable. Thanks to their special design specifications and the specific materials used, HRADIL special cables can be designed to withstand a great number of bending cycles.

 

See also alternating bending performance | alternating bending cycles

Block copolymers are molecule chains joined together in alternating blocks of hard and soft components.

Block polymers are obtained by mixing and subsequently vulcanising polymer blends and thermoplastics.

Braided shields (braided copper and steel wire) consist of a braid of several individual wires lying parallel (multiple-wound wire bundle) and are the most common shields used in cable manufacturing. The braid forms a mesh over the body to be shielded, achieving a degree of coverage of up to 85.

A downside to this method is the high degree of internal frictional resistance arising at the points where the wires cross. As a result, cables with braided shields that are subject to a large number of alternating bending cycles tend to have a shorter service life.

Braided copper wire is a very effective shield against electromagnetic fields with low frequencies and high frequencies in the upper MHz range. Optimal shielding results are achieved with 80 to 85% optical coverage.

Braided steel wire provides a good shield against electric fields and magnetic fields with low and medium frequencies.

Reinforced braids are primarily used to compensate for tensile forces on a cable. They protect the cores, all stranded components and the cable jacket against sometimes very high mechanical loads by absorbing strain.

At HRADIL Spezialkabel, these strain relief elements are welded onto the outer jacket of the cable in the form of a braid, integrated as a core in the centre of the cable, or applied outside of the central cable structure.

The following materials are used in reinforced braids for special cables

• Kevlar
• Aramid
• rayonRayon (synthetically manufactured viscose fibres made of natural basic materials)
• Metal reinforced braids made of V2A stainless steel

Bundle stranding is used in the construction of special cables in particular, because it is far superior to layer stranding when high mechanical loads (torsional loads) are involved. This is due to the fact that in layer stranding, the individual stranded components steadily increase in size from the inside to the outside. As a result, the stranded components on the inside may snap under high mechanical loads.

To counteract this tendency, bundle stranding joins three to five stranded components into bundles, which are then stranded.

Bundled litz wire is also known as bunched litz wire. It comprises individual strands which are bundled together in single process to form a litz wire. See also concentric litz wire.

Today there are cables for countless applications. Standard cables are designed to perform a pre-defined set of functions and leave little room for variations.

 

But the modern industrial world is changing rapidly, with automated production equipment, robots and transport systems becoming ever more powerful and complex. These developments go hand in hand with increasing requirements for components and cables and a growing need for special cables:

 

• Resistance to aggressive environmental conditions, including: heat, cold, humidity, flying sparks and chemicals
• Long service life over a great number of alternative bending cycles (millions!)
• Drum-reeling capacity
• A high degree of protection against electromagnetic radiation (EMC safety)
• Improved properties given the increased use of microprocessors and subminiature components.
• Explosion protection

See also:

 

• Cable manufacturing
• Types of cables
• Special cables

The CE marking (Conformité Européenne, “European Conformity”) is a marking used to identify specific products and their safety under EU law. Manufacturers use the CE marking to indicate that the product conforms to the applicable EU directives.

CERAMOFLEX^® is HRADIL’s registered trademark for special cables that, thanks to their high content of ceramic additives, meet the high thermal requirements for insulation integrity needed to earn an FE180 rating (180 minutes at 750°C without a short circuit). Despite their resilience, these cables are durable and extremely flexible.

In order to manage chemical requirements, insulation is a key factor in the design of HRADIL special cables, with considerations from HRADIL’s materials research team being taken into account. The following factors are particularly important:

 

• Water tightness
• Resistance to acid, oil and UV rays

Coaxial cables are suitable for transmitting high frequency signals. sewer inspection CCTV cablesSewer inspection CCTV cables typically include a coaxial cable as a camera cable for transmitting video signals.

In concentric litz wire, also known as unilay litz wire, the number of strands per layer as well as the length and direction of the lay are governed by set design specifications. This makes them much more complicated to manufacture than the comparatively inexpensive bundled litz wires.

Electrical conductivity is the most important property of conductive materials (litz construction) used in electrical engineering and electronics. See below for a comparison of technically pure metals:

 

Metal	Relative electrical conductivity	Relative thermal conductivity	Density
Silver	106	108	10.5
Copper	100	100	8.9
Gold	72	76	19.3
Aluminium	62	56	2.7
Magnesium	39	108	1.7
Zinc	29	29	7.1
Nickel	25	15	8.9
Cadmium	23	23	8.7
Cobalt	18	17	8.9
Iron	17	17	7.3
Steel	13-17	13-17	7.8
Platinum	16	18	21.5
Tin	15	17	7.3
Lead	8	9	11.3

E-Cu58F21 copper is a very versatile conductor material. Due to its very good electrical conductivity and outstanding warm and cold formability, electrolytic copper predominates in cable technology. Copper is manufactured with different surfaces depending on how it is processed and used.

 

Property	Copper
Electrical conductivity	Excellent Serves as the standard
Tensile strength	210 N/mm² with 15-20% extension
For alternating bending stress	Suitable
Solderability	Very good
Temperature range bare tin-plated silver-plated	+130°C +180°C +260°C

Unlike a braid, copper binding does not involve crossed wires. As a result, copper binding stands out for its high degree of flexibility and up to 95% coverage. Using dual cord shielding with the strands turning counterclockwise can compensate for the disadvantage of the shield opening up when subjected to high bending stress.

 

Copper wire binding is a very effective shield against electric fields with low and middle frequencies up to the lower MHz range. Single-layer binding exhibits good shielding properties, while multi-layered, criss-crossed binding makes an excellent shield.

Plastics or polymers are crosslinked in order to improve physical, chemical or mechanical properties such as resistance to pressure, oil or temperature, or the ability to be steam sterilised.

The degree of coverage indicates the optical density of the shielding. In braided shields, coverage is ideally between 85 and 90 percent. 
100 percent coverage is not technically feasible as the braid must have gaps in order to remain flexible. Achieving 100 percent coverage requires the use of a metallised film, for example.

Drum-reeling subjects a cable to extremely high mechanical loads. The reeling and unreeling of the cable drum places enormous strain on the interior of the cable.

 

Advanced stranding techniques, an open Kevlar braid which relieves strain, a durable cable jacket and many other features make HRADIL’s drum reeling cables masters of survival.

 

CE marking (Conformité Européenne: “Conformity with EU directives”) identifies certain products and their safety characteristics in accordance with EU legislation. By using the EC marking the manufacturer confirms that the product meets applicable European directives.

EEx approval is granted by an independent inspection authority and allows certain products to be used in potentially explosive environments. Example: Gas pipelines, offshore, etc...

Natural rubber is among the best-known elastomers, but it is of little importance in the cable industry today. Generally, elastomers are crosslinked – with rubber, this process is also known as vulcanization. Further additives are introduced into all elastomers in order to meet specific requirements.

In place of natural rubber, the cable industry primarily uses synthetic rubbers (typically based on ethylene and propylene):

• EPM (ethylene propylene rubber)
• EPDM (ethylene propylene terpolymer rubber)
• NBR (nitrile butadiene rubber)
• CR (polychloroprene)
• CM (chlorinated polyethylene)
• CSM (chlorosulfonated polyethylene)
• EVA (ethylene vinyl acetate)
• SiR (silicone rubber)

Thanks to their diverse properties, synthetic rubbers such as EPM and EPDM can be used in a wide range of applications and are especially suitable for flexible cables. They stand out for their good to very good resistance to cold and can be deployed at operating temperatures of up to 90°C. NBR, for example, is a good jacket material for applications where oil resistance is required.

Today, CR, CSM and CM in particular predominate in cable production (cables for mining and maritime applications). The benefits of these elastomers include their ability to withstand weather, chemicals, cold, heat, and flames as well as their good resistance to abrasion and tearing. EVA can additionally withstand temperatures of up to 110°C. However, the broadest temperature range is offered by silicone rubber. This material can tolerates temperatures from -60°C to +180°C, which is why it is frequently used in the manufacturing of special cables.

Electromagnetic compatibility (EMC) is the property of the cable which prevents it from causing electromagnetic interference and/or being affected by electromagnetic fields.

Background: Whenever supply lines, sensor and control cables are in close proximity to one another – in tight cable drag chains or thick cable bundles – electromagnetic fields are generated that are typical for automation and machine construction. Occasionally assemblies and hybrid cables can be quite a headache for engineers. Electromagnetic fields can cause noise that leads to severe signal degradation or even unwanted signals.

Electromagnetic compatibility (EMC) refers to the property of a cable which keeps it from causing electromagnetic interference and/or from being affected by electromagnetic fields. 

What you need to know: When supply lines, sensor cables and control cables are in close proximity as part of tight cable drag chains (energy chains) or thick cable bundles, electromagnetic fields, such as those typically found in automation and machine building, are generated. This may lead to the severe disruption of signals or even to unwanted signals. Assemblies and hybrid cables can also cause headaches for engineers in this regard.

When it comes to the environmental impact of cable materials, the primary concerns are requirements such as the use of halogen-free materials. Their performance under fire conditions, which includes the question of whether cables are self-extinguishing and ensure low toxicity/density of smoke is also important, however.

A fibre optic cable basically consists of a core firmly connected to surrounding cladding. The diameter of the optical fibre core is 9 µm, about ten times finer than a human hair. When the optical fibres are manufactured, the core and cladding are covered in a protective layer known as the primary coating. The secondary coating is an additional protective layer round the fibres. This protection may consist of one or more types of resistant plastic.

Das Biegewechselverhalten beschreibt die Haltbarkeit eines Kabels bei permanenter Biegung in wechselnde Richtungen. Eine S-förmige Umlenkung eines Kabels beschreibt auch eine Art der Wechselbiegung.

This (also referred to as flexural or flexing cycle loading) refers to a cable’s elongation on the outside and compression on the inside. By applying special engineering specifications and utilizing state-of-the-art materials, Hradil is able to manufacture Special cables that will withstand more than 25 million flexing cycles.

Modern automated production machines, robots and transportation systems require cables that are capable of withstanding enormously high mechanical stress. Automated machinery with ancillary handling systems can involve both stretching and rotating motions. In such cases the cables are subjected to enormous reverse bending stresses at tight radii. This is why it is so important to select the right materials for the job, such as alloy litz wires, in order to guarantee the cable’s long-term durability.

Thermoplastic fluoropolymers have excellent chemical and thermal properties as well as very good insulation values. However, they are also very expensive by comparison and the processing costs are significant. Distinctions are made between the following fluoropolymers:

• PTFE (polytetrafluoroethylene) – Due to its good electrical, thermal and mechanical properties in applications with very thin walls, PTFE is especially popular in aircraft manufacturing and rocket technology.
• PVDF (polyvinylidene fluoride) – PVDF is the most cost-effective of all of the fluoropolymers.
• ETFE (ethylene tetrafluoroethylene) – ETFE offers an even better operating temperature range than PVDF, withstanding temperatures of between -65°C and +180°C.
• FEP (fluorinated ethylene propylene) – Of all of the fluoropolymers, FEP offers the best overall properties, but is also the most expensive.
• PFA (perfluoroalkoxy alkane) – Thanks to its specific properties, PFA is suitable for use in even more demanding applications than FEP. It tolerates temperatures between -200°C and +250°C.

foil shieldUnlike core shields and braided shields, foil shields (aluminium laminated polyester foil) are also effective in the high frequency range. In addition, they are ideal for applications that lack the space for much larger cord or braided shields. However, it’s important to note that foil shields can shift inside flexible cables.

Depending on the type and strength of material selected, foil shields provide the most effective protection against electric and magnetic fields, with aluminium and copper foils offering protection against electric fields and iron foils offering protection against magnetic fields. Multi-layered foils using various materials effectively protect against both low and very high frequencies

When manufactured with the right materials, cables can handle extreme thermal loads, such as heat up to +250°C and extreme cold of as low as -200°C.

 

PUR, for example, is especially suitable for use in outer jackets for cables deployed at low and high temperatures. Conductors made of pure nickel are used at extremely high temperatures of up to 500°C. Banding of quartz and silica glass can be used to protect electric cables from flame and heat of up to 1100°C.

 

HRADIL’s CERAMOFLEX^® cable offers extreme heat resistance.

Hybrid cables combine multiple properties and functionalities in a single cable. The types of cables include fibre optic cables, coaxial cables and even pneumatic hoses.

Hydrosilicon crosslinking is a two-stage wet chemical process. It used mainly to crosslink polyethylene. Its advantages over radiation crosslinking may be seen in a more homogenous distribution of the crosslinked areas resulting from the silicon molecules dispersing in the molten mass. Other advantages are in the lower investment and energy costs (e.g. no need for radiation shielding measures). The most convincing aspects of hydrosilicon crosslinking are greater resistance to ageing and improved mechanical properties.

The degree of imbrication defines the visual density or coverage of shielding material. Ideally the imbrication level of braided shielding should be between 85 and 90%. It is technically impossible to achieve 100 percent because the braid must have gaps to make it flexible. You would have to use metal-laminated film, for example, to achieve a 100% imbrication level.

Operational safety, service life and environmental impact are the key criteria for determining the materials used in cable insulation and jackets. But of course costs also play a significant role. In addition to procurement costs, material consumption and the costs of processing materials should also be taken into account.

 

HRADIL Spezialkabel makes use of all of the materials available on the market, employing completely different combinations of materials depending on the application.

 

Multi-layered dielectrics made of impregnated paper wrapping are considered the classical insulation material and were especially common in the first half of the 20th century. Due to its good dielectric properties, this form of insulation is still used in high-voltage cables today, though only to a limited extent.

 

The following state-of-the-art insulation and jacket materials are predominantly used in cable construction today:

 

Thermoplastics

Crosslinked thermoplastics

Elastomers

Thermoplastic elastomers TPE

Kevlar is one of the best-known brand names for aramid fibres, which are classified as liquid-crystal polymers. Kevlar fibres were developed by DuPont in 1965 and are sold under the brand name Kevlar™.

Kevlar is very resistant to wear and tear, and is used for applications involving extreme mechanical loads. In addition to their high tensile strength, plastic fibres such as Kevlar offer the advantage that they weigh far less than a metal reinforced braid.

 

See also: Reinforced braids made of Kevlar

Cables can be stranded to the right or to the left. In a right-stranded cable, the individual conductors (moving away from the observer) are wrapped clockwise around the core. Stranding to the right is known as Z-twist and stranding to the left as S-twist.

Lay length refers to the pitch of the elements stranded helically around the core of a cable. It indicates the distance, measured in the axial direction of the cable, required for a stranded element (such as a conductor) to make one full turn (360 degrees) around the core.

The purpose of a cable has a decisive influence on the choice of conductor. A distinction is made between solid conductors and litz conductors. Litz conductors, either in the form of bunched litz wires or concentric litz wires, are predominantly used in the special cable manufacturing. At HRADIL Spezialkabel, litz wires are available with diameters ranging from 0.08 mm² to 300 mm², depending on the configuration of the conductor.

 

Due to rapid developments in the manufacture of special cables, high-performance and reliable conductor materials are needed. HRADIL Spezialkabel uses litz wires made of the following conductive materials:

 

Copper

Pure nickel

Alloy

 

The material colours and core printing used for HRADIL cables can be tailored to customer requirements. Alongside these company-specific designations and colours, there are also certain colours and colour combinations that are subject to restrictions. The best-known colour combination is the use of yellow-green to signify protective conductors. Cable jackets that are used in intrinsically safe electrical circuits are identified with the colour blue.

Moving elements are especially common in industrial applications, such as those in automation and robot technology. Cables for these applications must be equipped to handle a broad range of mechanical stressors.

 

• Torsion and tensile strength
• Alternating bending cycles
• EMC safety
• Highly abrasion-resistant material

 

All special cables manufactured by HRADIL undergo extensive testing regarding their mechanical strength. Essential design principles arise from the proper selection of:

 

• Litz wire
• Shielding
• Banding
• Braiding
• Stranding
• Insulation

Mobile cranes at ports handle all kinds of goods – containers, bulk cargo, general cargo and project goods. Unlike rail-mounted cranes, mobile cranes have very complex chassis constructions and can be used in a significantly wider range of applications, thanks to their mobility.

Mobile harbour cranes handle all kinds of goods – from containers and bulk cargo to general cargo and project goods. Unlike rail-mounted cranes, mobile cranes have very complex chassis and, thanks to their mobility, can be used in a wider variety of applications.

Multiple winding refers to the number of separate adjacent wires in a shielding braid.

Non-woven fabric is a thin, felt-like material made of synthetic fibres that is typically used as ribbons to separate the various layers of a cable.

The term optical fibre has been nationally standardised in the DIN 47002 and VDE 0888 standards and refers to a fibre along which modulated light is transmitted. Light moves along optical fibres at a speed of 299,792.458 km/s. The international glass fibre cable standards that apply to optical fibres or glass fibres are ITU-T G.651 to G.657, ISO/IEC 11801 and 24702, and IEC 60793.

 

See optical fibre construction

See optical fibre transmission loss

See fibre-to-the-home

Optical fibres consist of a core and a cladding material, which are firmly attached to one another. With a diameter of 9 µm, a fibre optic core is about ten times thinner than a human hair. When the fibres are manufactured, a protective layer known as the primary coating is applied to the core and the cladding. An additional protective layer known as the secondary coating is applied around the fibres. This coating consists of one or more identical or different types of solid plastic.

 

See optical fibre transmission loss
See optical fibre

See fibre-to-the-home

 

Transmission loss is minimal in optical fibres. The microstructure of the ultrapure glass is the only thing that interferes with the light wave, thereby resulting in attenuation. Attenuation is caused by factors such as distance and wavelength, losses due to absorption, diffusion and radiation, as well as connecting elements and splices.

 

See optical fibre construction

See optical fibres

See fibre-to-the-home

The term optical fibre (German: LWL) is nationally standardised in Germany in standards DIN 47002 and VDE 0888. The term refers to a fibre along which modulated light is transmitted, whereby the light travels through the fibre at 299,792,458 km/s. International standards for fibre optic cables are: ITU-T G.651 to G.657, ISO/IEC 11801 and 24702, and IEC 60793.

Due to its very good mechanical properties (high mechanical strength and hardness, good abrasion resistance, good resistance to temperatures as low as -50°C, good resistance to chemicals and weather), polyamide.... However, due to its limited electrical properties, it is often used as secondary insulation.

Pair stranding is the simplest type of stranding, using a pair of cores to create a new stranded component.

PE is a thermoplastic that is predominantly used as insulation in telecommunication cables due to its very good dielectric properties. It is halogen-free and has good mechanical properties, but with the drawback that it is highly combustible.

Peroxides (such as benzoyl peroxide) are used in industrial applications as radical initiators. Weak peroxide bonds can be easily cleaved homolytically, thereby forming reactive benzoyl radicals. In large-scale industrial applications, these benzoyl radicals are used to polymerise plastics such as polyethylene.

Plasticisers refer to substances added to hard thermoplastics to improve their elasticity, softness and flexibility during processing and use. Plasticisers do not react chemically with the material, but only modify its physical properties.

Substances added to rigid thermoplastics to improve their distensibility, softness and pliancy during processing and afterwards in use. Plasticizers, however, do not react chemically with a material but only alter its physical properties.

Polyblends consist of hard plastic segments that are embedded like islands in an elastic base material.

PP belongs to the same family as PE. Like PE, it is halogen-free, but it performs better when exposed to fire.

PTFE film is made of polytetrafluoroethylene that is skived to achieve the desired thickness. It is often used as a friction-free film between various components inside a cable, for example in drum-reeling cable structures. PTFE can withstand extreme thermal loads.

PUR is a popular abbreviation for polyurethane, a plastic with excellent mechanical properties. Due to its outstanding abrasion and notch resistance, it is primarily used for cable jackets. PUR is available in various degrees of hardness depending on the degree of flexibility and other properties required.

Pure nickel is a very heat-resistant conductor material. Conductors made of pure nickel are used at extremely high temperatures of up to 500°C. However, high temperature resistance is associated with only average electrical conductivity.

 

Property	Pure nickel
Electrical conductivity	Average: approx. 20% of the electrical conductivity of copper
Tensile strength	450 N/mm² at 15-20% elongation
For alternating bending stress	Not suitable
Solderability	Possible
Temperature range bare tin-plated silver-plated	+500°C

PVC is well known as a “mass-market” plastic, and is an important material in the production of cable jackets and insulation. When used in cable manufacturing, plasticisers, stabilisers, fillers and additives (lubricants, pigments, waxes, and matting agents) are added to traditional hard PVC to modify it into PVC-P.

 

HRADIL Spezialkabel uses more than 50 different formulations for its PVC-P blends. Depending on the application, different amounts of plasticisers are added in order to achieve PVC-P in various degrees of hardness (Shore A hardness). The disadvantages to PVC are its high dielectric loss factor and its strong smoke production (corrosive gases) under fire conditions. As a result, HRADIL Spezialkabel only uses this plastic in a few exceptional cases.

 

Radiation crosslinking is a form of physical crosslinking using electron beams (gamma rays). In order to generate the high-energy radiation required for crosslinking with electron beams, and especially gamma rays, a complex system is required.

Physical crosslinking using electron beams (gamma rays). Crosslinking with electron beams, especially gamma rays, demands an elaborate system to generate high-energy radiation.

Acid-, oil- and UV ray-resistant cables are a classic field in special cable manufacturing. The production of such cables relies on a wide variety of materials, but thanks to its excellent resistance to oils and chemicals, modern polyester-based plastic is often used.

The demand for self-extinguishing cables with fire-retardant properties can generally be met by adding chlorine, fluorine and bromine flame retardants.

In order to keep the toxicity/density of smoke low and minimise environmental impact, halogen-free cables are needed.

Sewer inspection CCTV cables are used to operate sewer cameras, sewer robots and sewer renovation systems. Sewer inspection CCTV cables typically comprise a coaxial cable as a camera cable for transferring video signals and several conductors to control and illuminate the camera system, which is usually self-propelled.

 

HRADIL Spezialkabel offers a variety of compatible replacement cables for most sewer cameras, sewer robots and sewer renovation systems at www.kanalkabel.de.

Shields play a key role in cable manufacturing Not only do they ensure that radiation from electric and electromagnetic fields cannot penetrate into the cable, they also prevent any electric and electromagnetic fields generated by the cable itself from radiating outwards. Shielding is an especially important topic when it comes to the stringent requirements for EMC safety.

 

HRADIL Spezialkabel uses the following shielding methods, which may also be combined for particularly high-value applications:

 

• Braided copper and steel wire as braided shields (C shields)
• Copper binding as core shields (D shields)
• Aluminium laminated polyester film as foil shield shields (static shields)

Shore hardness testing measures hardness by determining a material’s resistance to indentation. Named after Albert Shore, this value is widely used, especially in plastics testing. 

In Shore durometer tests, a test piece is struck with a spring-loaded test pin in order to measure the material’s resistance to indentation. 

Shore hardness values are non-dimensional and recorded on a scale of 0 to 100. The softer the material, the deeper the test pin will penetrate it. Shore A and D methods differ in terms of the form of the test pin’s spike and the amount of force applied.

Silane crosslinking is a two-step, wet chemical process, which is primarily used to crosslink polyethylene. One advantage of this method over radiation crosslinking is that the silane molecules are dispersed in the molten mass, resulting in a more homogenous distribution of crosslinked areas. Other advantages include lower investment and energy costs (as there is no need for radiation protection measures) as well as greater resistance to ageing and improved mechanical properties.

Solid conductors are only used when cables are fixed and therefore not subject to mechanical loads such as alternating bending cycles.

HRADIL Spezialkabel manufactures special cables in accordance with customer requirements for every imaginable application. We draw on our decades of experience and plenty of design ingenuity, while also taking the following parameters into account for:

 

Litz wires

Types of cables

Shielding

Banding

Reinforced braids

Stranding techniques

Insulation and jacket materials

Material colours and core printing

Standard cables (such as the classic 220 volt electrical cable) are cables that are made in accordance with existing explicit standards. In contrast, special cables are designed for a specific purpose or a specific special application.

Depending on the purpose of the cable, cable elements may be stranded, with several very different machines being used for stranding. This makes it possible to create stranding without backtwist. This type of stranding is especially important to ensure that cores are positioned so as to avoid mechanical strain.

 

Distinctions are made between three different stranding techniques:

 

• Pair stranding

• Layer stranding
• Bundle stranding

In order to ensure that a cable offers high tensile strength, the complete cable structure must be designed with this in mind. For example, the use of a reinforced braid made of Kevlar offers much higher tensile strength than a conventional metal reinforced braid.

 

The author offers no guarantee for the currency, correctness, completeness or quality of the information provided.
Liability claims against the author that make reference to material or immaterial damages caused by the use or non-use of the information provided or by the use of incorrect or incomplete information are expressly excluded, provided that no deliberate or grossly negligent fault on the part of the author can be shown to exist. The information provided in the glossary and on the website more generally does not constitute an agreement on quality and should be verified in each individual case.

 

 

 

HRADIL special cables are optimised in accordance with thermal requirements. The selection of litz wires, banding and insulation, among other aspects, are an important part of the design.

 

Heat-resistant cables/cold-resistant cables

Self-extinguishing materials

Thermoplastic elastomer (TPE) is an umbrella term for ethylene-based thermoplastic elastomers.

TPEs are the result of an attempt to combine the positive performance characteristics of elastomers with the convenient processing properties of thermoplastics. These two materials are combined by synthesising what are called block copolymers, the use of polyblends or block polymers. Thermoplastic elastomers are also commonly referred to as TPR (thermoplastic rubber).

 

Well-known thermoplastic elastomers include:

TPE-E (thermoplastic polyester elastomer)

TPE-A (thermoplastic polyamide elastomer)

TPE-U (thermoplastic polyurethane elastomer)

TPE-O and TPE-V (thermoplastic polyolefin elastomer)

TPE-S (thermoplastic polystyrene elastomer)

Thermoplastics are frequently used in cable manufacturing. The following may be considered:

 

PVC (polyvinylchloride)

PE (polyethylene)

PP (polypropylene)

PA (polyamide)

Fluoropolymers

Torsional loads put strain on a cable by twisting it around its own axis. Completely different design principles are used to manage torsional loads as compared to bending stress or tensile strength. Thanks to their bespoke design, cables manufactured by HRADIL Spezialkabel can be twisted up to 320°.

TPE-A offers the same good mechanical and chemical properties as TPE-E, with the added advantage of better resistance to acids and bases.

Thermoplastic polyester elastomers (TPE-E) can be produced with different formulations, with properties ranging from softer to harder. Depending on the amount of of plasticiser used, such as polyalkylene glycol ether, Shore hardness values from D 38 to D 74 can be achieved. The service temperature of TPE-E is between 40°C and 120°C. Due to its excellent performance under dynamic loads, TPE-E is a popular material in special cable manufacturing. Its high resistance to alternating bending stress and its high impact strength are worthy of note, and its resistance to chemicals, oils and solvents is another point in its favour.

TPE-O and TPE-V have a broad range of mechanical values, which can be individually modified. Although thermoplastic polyolefin elastomers do not perform as well at high temperatures, their excellent electrical properties make them an attractive option.

TPE-S has very similar properties to thermoplastic polyolefin elastomers, but may sometimes offer greater flexibility or better performance under alternating bending stress.

Thermoplastic polyurethane (TPU) is one of the best-known thermoplastic elastomers. Commonly known as PUR or polyurethane rubber,

it is easy to process and features excellent mechanical and chemical properties, making it the preferred material for flexible cables.

In twisted-pair cables two conductors are twisted around each other. The twisting can be performed to different degrees and also the lay length can differ. Compared to conductors that have been stranded in parallel, a twisted pair of conductors provides better protection against electro-magnetic interference (EMI), which makes them the ideal choice for telecommunication, data transmission and computer systems.

The need for special cables continues to grow. At HRADIL Spezialkabel, we are prepared for this. Our research into materials for conductors and insulation in particular allows us to offer tailored HRADIL special cable solutions such as:

 

• Control cables
• Drag chain cables
• Resolver cables
• Hybrid cables
• Hybrid fibre optic cables
• Combination cables with integrated hydraulics and pneumatic hoses
• Sewer inspection CCTV cables
• Armoured cables
• Offshore and ship cables
• Cables for potentially explosive environments
• Crane cables
• Cables for cranes & mobile harbour cranes
• Coaxial cables
• Low temperature cables
• High temperature cables (CERAMOFLEX^®)
• Drum-reeling cables
• Heat-resistant cables
• CAN bus cables
• Drag chain cables