Introduction
Copper and Aluminium Wire Drawing Process | Learn How Electrical Wires Are Made
Introduction
Electric wires are an essential part of our daily lives. From homes to industries, electricity powers everything, and for this purpose, copper and aluminium are the most widely used metals. In this article, we’ll understand how these metals are drawn into fine electrical wires through a step-by-step wire drawing process and what machinery and materials are required for it.
Materials and Machinery Required for Wire Drawing
- Copper (Cu)
- Aluminium (Al)
- Drawing Oil (Lubricant)
- RBD – Rod Breakdown Machine
- Intermediate Drawing Machine
- Fine Drawing Machine
- Annealing Machine
Copper (Cu)
Copper is the most widely used metal for electrical wire manufacturing. It has high electrical conductivity and low resistance, which allows smooth and efficient current flow. Because of its excellent performance, copper is used in almost all types of electrical wires and cables. However, the main drawback is its higher price, which is why aluminium is often used as a cost-effective alternative.
Aluminium (Al)
Aluminium is also widely used for wire production, especially in power and transmission cables. Compared to copper, aluminium has slightly lower conductivity and higher resistance, but it is much lighter and cheaper. This makes it ideal for heavy-duty cables, overhead transmission lines, and industrial applications. Using aluminium significantly reduces the overall production cost while maintaining acceptable performance levels.
RBD (Rod Breakdown Machine)
The RBD machine is the first and most important step in wire drawing. In this stage, 8.0 mm or 9.5 mm copper/aluminium rods are drawn down to approximately 2.5 mm wires. The machine uses multiple dies, and each die reduces the wire’s diameter gradually. Lubrication and cooling systems are used to prevent the wire from overheating.
Input Size: 8.0–9.5 mm
Output Size: 2.5 mm
Intermediate Drawing Machine
The intermediate machine further reduces the wire size from 2.5 mm to 1.0 mm. This stage requires precise tension control and lubrication to maintain smooth surface quality and accurate diameter. Proper cooling is also essential to avoid wire breakage.
Input Size: 2.5 mm
Output Size: 1.0 mm
Fine Drawing Machine
The fine drawing machine performs the final wire reduction process. Here, the 1.0 mm wire from the intermediate stage is drawn down to the required final sizes — typically 0.75 mm, 0.5 mm, or finer. This high-speed machine ensures uniform diameter and excellent surface finish, which directly affects the wire’s quality and performance.
Input Size: 1.0 mm
Output Size: 0.75 mm or 0.5 mm
Annealing Machine
After drawing, the wire becomes hard and brittle due to work-hardening. To restore flexibility, the wire is passed through an annealing furnace, where it is heated between 300°C – 600°C and then slowly cooled. This process softens the wire, improves conductivity, and enhances mechanical strength.
Advantages of Annealing:
- Increases wire flexibility (easy to bend and handle)
- Improves electrical conductivity
- Enhances tensile strength and durability
After annealing, copper and aluminium wires are ready for PVC or XLPE insulation and then used to manufacture final electrical wires and cables.
Conclusion
The complete process — RBD → Intermediate → Fine Drawing → Annealing — transforms copper and aluminium rods into fine, high-quality electrical wires. These wires are then insulated and used in homes, factories, and power transmission systems across the world. The quality of wire drawing directly affects electrical safety and efficiency, making it one of the most critical processes in cable manufacturing.
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