The heat dissipation efficiency of a radiator hinges on the quality of the connection between the base and the fins. This "heat conduction pair" needs a seamless connection to fully unleash the thermal conductivity advantages of copper (thermal conductivity 401 W/(m・K)) or aluminum (200-230 W/(m・K)). While ultra-thin fin designs (0.1-0.5mm) maximize heat dissipation area, they present significant challenges to the connection process.
Traditional welding processes have long been constrained by technological limitations. Brazing requires a high-temperature environment of 400-600℃, at which ultra-thin aluminum sheets are extremely prone to bending and deformation, and an oxide layer with a thermal conductivity of only 1-3 W/(m・K) forms on the metal surface, effectively creating a "heat insulation wall" between the heat source and the fins. While laser welding can improve precision, the localized high temperatures exceeding 1000℃ can cause grain coarsening, reducing the thermal conductivity of copper and aluminum by 5%-10%, directly weakening heat dissipation performance. In the mass production of precision products such as computer CPU heatsinks, manual operation often leads to inconsistencies such as cold solder joints and over-soldering.
The emergence of ultrasonic soldering irons offers a new solution to this industry pain point. Its low-temperature soldering characteristic of 150-250℃ reduces heat input to 1/3-1/5 of traditional processes, effectively preventing thermal deformation even for ultra-thin fins less than 0.1mm thick. More importantly, the high-frequency vibration of 20-40kHz mechanically breaks down the oxide layer on the metal surface, achieving molecular-level diffusion bonding without flux, thus eliminating the "thermal conductivity bottleneck" at its source.
Joints created using this soldering method exhibit excellent thermal conductivity. Because it eliminates the need for low-thermal-conductivity solder (typically <100 W/(m・K)), the thermal conductivity of aluminum joints can exceed 180 W/(m・K), and copper joints exceed 350 W/(m・K), approaching the thermal conductivity of the base material itself. With precise control of 5-20μm amplitude and 5-30N pressure, the thermal resistance of the solder joint can be as low as 0.15℃・cm²/W, significantly superior to traditional processes.
In mass production scenarios, the advantages of this technology are even more pronounced. Through intelligent parameter adjustment, it can meet the soldering requirements of CPU heatsink fin arrays while avoiding errors from manual operation. The soldering strength is increased by more than 50% compared to traditional processes, and it can pass more than 500 thermal cycle tests, ensuring long-term reliability.
From the thermal resistance test data, heatsinks using ultrasonic welding improve heat transfer efficiency from the base to the fins by nearly 30%. This technological breakthrough not only drives the upgrading of heat dissipation products towards thinner and more efficient designs but also provides crucial support for the thermal management of electronic devices.
