Key Points for Copper/Aluminum Heatsink Fin Welding
Key Points for Copper/Aluminum Heatsink Fin Welding – Sonic4lab
In the heat dissipation systems of high-end equipment such as new energy vehicles, data centers, and 5G base stations, the welding quality of copper/aluminum heatsink fins to the substrate directly determines heat dissipation efficiency and equipment lifespan. The high thermal conductivity of copper and the lightweight advantage of aluminum complement each other, making copper/aluminum combinations a preferred solution for heat dissipation devices. However, the significant differences in their physical properties make precise control of the welding process crucial.
Scientific selection of welding materials is fundamental to ensuring joint quality. Due to the high reactivity of aluminum, an oxide layer easily forms during welding. Traditional welding requires the use of flux, while new flux-cored welding materials can achieve welding without additional flux, significantly improving joint density. For different gap requirements, welding materials with varying fluidity can be selected: those with better fluidity are suitable for small gap welding, while those with higher welding strength and easier accumulation should be selected for large gap workpieces to ensure complete weld filling.
Detailed process control is essential throughout the entire welding process. Before welding, the area within 20mm of the welding area must be thoroughly cleaned. Use organic solvents to remove oil and use metallographic sandpaper to remove the oxide layer, preventing impurities from affecting the weld bond. The joint design should preferably use lap or socket joints, avoiding butt joints. The socket gap must be strictly controlled within the range of 0.05~0.15mm to account for capillary action and differences in thermal expansion. During welding, uniform heating is required, prioritizing heating of copper parts with better thermal conductivity. Add welding materials only after reaching a brazing temperature of 450-500℃ to prevent direct melting of the welding materials from affecting the bonding effect.
The application of advanced welding technology drives upgrades in heat dissipation performance. Vacuum diffusion welding, as a preferred process in high-end fields, achieves atomic-level interface bonding through a high-temperature and high-pressure environment. It forms a metallurgical bond with near-base material thermal conductivity without the need for solder, reducing joint thermal resistance by more than 70% and withstanding extreme thermal cycling tests from -55℃ to 150℃. Post-weld natural cooling and cleaning are equally crucial. During cooling, the fixture must be kept fixed to prevent residual stress from causing cracks. After welding, flux residue should be removed by hot water soaking or acid pickling to prevent corrosion and weakening of the joint strength.
The mature application of copper/aluminum heat sink fin welding technology to the substrate has achieved the dual requirements of “high-efficiency heat conduction + lightweight” in heat dissipation systems. In core components such as power battery liquid cooling plates and chip heat sinks, high-quality welded joints improve heat dissipation efficiency by more than 50%, significantly enhancing equipment operational stability. With continuous process optimization, this technology will continue to provide core support for the upgrading of thermal management in high-end manufacturing.
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