Modern cars are like computers on wheels, equipped with complex electronic systems. The uninterrupted and safe operation of these systems is directly dependent on the quality of the automotive cables that form the vital connection points inside the vehicle . Used in everything from engine control units to infotainment systems, from safety sensors to lighting, these cables are specially manufactured to withstand harsh environmental conditions. The production processes of automotive cables are carried out meticulously from material selection to testing stages, ensuring compliance with international quality standards.
Material Selection in Automotive Cables: A Balance of Performance and Durability
The performance, longevity and safety properties of automotive cables depend on the correct choice of conductor, insulation and protective sheath materials used.
Conductive Materials: Electrical Efficiency
- Copper: It is the most commonly used conductive material in automotive cables. It offers reliable performance thanks to its high electrical conductivity, good thermal conductivity and corrosion resistance. It is especially preferred in power cables carrying low voltage signals and high current.
- Aluminum: Because it is lighter and cheaper than copper, aluminum conductors are used in some applications (especially in power cables with thicker cross-sections). However, aluminum's lower conductivity and higher propensity to oxidation than copper may require special alloys and plating techniques. It is more brittle than copper and requires special precautions at the connection points.
- Copper Alloys: Alloys are used to improve the mechanical properties of copper, especially in applications that require higher resistance to vibration and bending.
Insulation Materials: Resistance to Environmental Conditions
Insulating materials isolate conductors from each other and from the external environment, preventing short circuits and maintaining signal integrity. They need to withstand the rigors of the automotive environment, such as extreme temperatures, humidity, chemical exposure, and vibration.
- PVC (Polyvinyl Chloride): It is a cost-effective insulation material that offers flexibility over a wide temperature range. It has good electrical properties. However, its performance may decrease in case of exposure to high temperatures (usually above 105°C).
- XLPE (Cross-Linked Polyethylene): It is superior to PVC in terms of high temperature resistance, chemical resistance and abrasion resistance. The crosslinking process increases the thermal stability of the material and makes it more resistant to melting. Ideal for engine compartment and other high temperature applications.
- TPE (Thermoplastic Elastomer): It is a hybrid material that offers both the workability of thermoplastics and the flexibility of rubbers. It retains its flexibility over a wide temperature range and is resistant to vibration and abrasion. It is especially preferred in applications where flexibility and high performance are sought together.
- Silicone: Excellent resistance to very high and very low temperatures. It is often used in places where there are extreme temperature changes, such as in the engine compartment. However, its cost is higher than other materials.
Protective Sleeve Materials: Mechanical and Chemical Protection
The outer sheath protects cables from physical damage, abrasion, moisture, and chemicals.
- PVC: Commonly used in general purpose cables.
- Polyethylene (PE): It is used where moisture and chemical resistance is needed.
- Polyurethane (PU): It is a sheath material with high abrasion and tear resistance, flexible and resistant to harsh environments.
- Nylon Coating: A thin layer of nylon can be applied over the insulation to increase wear resistance.
Automotive Cable Production Stages: Meticulousness and Precision
The production of automotive cables is a complex process that must be meticulously controlled at every stage.
- Wire Drawing: Large diameter metal rods (copper or aluminum) are repeatedly passed through smaller molds and turned into conductive wires of the desired thickness. This process directly affects the surface smoothness, homogeneity, and mechanical properties of the wire.
- Stranding/Bunching: The thin wires obtained are brought together in a certain pattern and direction to create thicker and more flexible conductor bundles. This twisting process increases the cable's flexibility, vibration resistance, and current-carrying capacity. The stranded structure is more durable and reliable than the single-stranded conductor.
- Insulation Extrusion: On the bent conductor, the molten insulation material (PVC, XLPE, TPE, etc.) is homogeneously coated by means of an extruder machine. Thickness, concentricity, and surface finish are critical at this stage. In materials such as XLPE, a cross-linking process is applied to cross-link the material after extrusion.
- Cabling/Twisting: Individual insulated conductors are joined together with a specific twisting step to form a multicore cable. This twisting increases the mechanical strength of the cable and improves electromagnetic compatibility (EMC).
- Jacket Extrusion: The last protective outer sheath is extruded on the joined veins. This sheath provides the mechanical protection and environmental resistance of the cable. In some cases, shielding (e.g. foil or mesh) can be added before or after this stage.
- Marking and Length Measurement: Brand , type, section and other information are printed on the produced cable in accordance with the standards. It is cut into the correct lengths and wrapped.
- Testing and Quality Control: Extensive testing is carried out at every stage of production and the final product.
Quality Standards: The Basis of Safety
Because automotive cables are critical to vehicle safety and performance, they are subject to very strict international and industry-specific quality standards.
- ISO (International Organization for Standardization):
- ISO 6722: Specifies general requirements and test methods for 60V and 600V single or multicore, insulated low-voltage cables for road vehicles. It includes mechanical, thermal and electrical performance criteria.
- ISO/TS 16949 (Now IATF 16949): The quality management system standard for the automotive industry. It ensures that all companies in the supply chain meet the specific requirements of the automotive industry and promotes continuous improvement.
- SAE (Society of Automotive Engineers):
- SAE J1127/J1128: Defines general requirements, dimensions, test methods and performance characteristics of low-voltage automotive cables. According to cable types (eg. GPT, GXL, SXL, TXL) provide detailed specifications. In particular, these standards determine the properties of the cable, such as temperature resistance, abrasion resistance and flexibility.
- OEM (Original Equipment Manufacturer) Standards: Large automotive manufacturers (Volkswagen, BMW, Mercedes-Benz, Ford, General Motors, etc.) can set their own specific and more stringent standards in addition to these international standards for cables to be used in their vehicles. These standards are shaped by the unique requirements and environmental conditions of specific vehicle models. They usually include more specific tests and criteria on issues such as chemical resistance, flame retardancy, vibration resistance, and electrical performance.
- RoHS (Restriction of Hazardous Substances): It is a directive set by the European Union that restricts the use of certain hazardous substances in electronic and electrical equipment. In automotive cables, substances such as lead, mercury and cadmium must be below certain limits.
The production of automotive cables is much more than just a simple combination of wire and insulation. Advanced engineering knowledge, high-quality material selection, and rigorous manufacturing processes that comply with international standards ensure that these critical components are indispensable for vehicle safety and performance.
