The casting process of tubular busbars requires high-purity conductive materials, precise mold design, controlled heating and cooling, and strict adherence to electrical and mechanical standards.

Material Selection

Tubular busbars are typically made from high-purity copper (ETP C11000, 99.9% purity) or aluminum alloys (6101-T6 or 6063-T6) to ensure optimal electrical conductivity and mechanical strength. Copper is preferred for high-current applications due to its superior conductivity, while aluminum is lighter and more cost-effective for moderate current loads .

Mold Design and Preparation

The casting process begins with accurate mold design to achieve the desired tubular shape and wall thickness. The mold must account for thermal expansion, shrinkage, and uniform wall thickness to prevent defects such as voids or warping. Proper mold release agents and insulation are essential to maintain surface quality and prevent sticking .

Casting Process

1. Melting: The selected metal is melted in a controlled furnace to the appropriate temperature, ensuring uniformity and avoiding oxidation. Copper requires careful temperature control to prevent grain coarsening, while aluminum alloys need fluxing to remove impurities .
2. Pouring: Molten metal is poured into the tubular mold under controlled conditions to minimize turbulence and air entrapment, which can cause porosity.
3. Cooling and Solidification: Controlled cooling is critical to prevent internal stresses and cracks. Slow, uniform cooling ensures consistent mechanical properties and dimensional stability .
4. Surface Treatment: After casting, the busbar surface may be polished, coated, or plated (e.g., tin or silver) to prevent oxidation, improve conductivity, and enhance durability .

Machining and Finishing

Post-casting, tubular busbars often undergo punching, drilling, and bending to meet installation requirements. CNC machines are used to maintain tight tolerances (±0.1 mm) and precise hole placement for bolted connections. Bending must respect the minimum radius (≥1.5× thickness) to avoid stress fractures .

Quality Control

• Visual Inspection: Check for surface defects, cracks, or porosity.
• Electrical Testing: Verify conductivity and current-carrying capacity.
• Dimensional Verification: Ensure compliance with design specifications and tolerances.
• Standards Compliance: Follow relevant standards such as GB 5585.1-2005 and GB 5585.2-2005 for copper busbars and general electrical equipment requirements .

Safety and Handling

Proper personal protective equipment (PPE), ventilation, and handling procedures are essential during casting to prevent burns, inhalation of fumes, and electrical hazards. Insulation and coating are also critical to prevent short circuits and corrosion during operation .

Summary

The casting of tubular busbars is a precision-driven process that integrates high-quality materials, controlled thermal management, accurate mold design, post-casting machining, and rigorous quality control. Adhering to these requirements ensures reliable electrical performance, mechanical integrity, and long-term durability in industrial applications.