Thermal heatsink Reflow Soldering Process

    Reflow soldering is one of the main processes of heatsink assembly. Reflow soldering is mainly used to weld the assembled thermal parts, melt the solder paste by heating to weld the parts together, and then cool the solder paste through the cooling of reflow soldering to solidify the components and solder paste together. Reflow furnace is a very extensive application at present, which is basically used by most manufacturers. To understand reflow welding, we must first understand SMT process. Of course, generally speaking, it is welding, but reflow welding provides a reasonable temperature, that is, furnace temperature curve.

Why is called reflow soldering:

       Originally, the solder paste is mixed with some chemicals such as metal tin powder and flux, but the tin in it can be said to exist independently as small tin beads. After passing through the equipment such as reflow furnace, after several temperature zones and different temperatures, when the temperature is greater than 217 ℃, those small tin beads will melt. Through the catalysis of flux and other items, countless small particles will melt into one, In other words, those small particles return to the flowing liquid state. This process is often referred to as reflux, which means that the tin powder returns to the liquid state from the previous solid state, and then returns to the solid state from the cooling zone.

temperature curve:

    Temperature curve refers to the curve that the temperature at a certain point on the radiator changes with time when the radiator passes through the furnace. The temperature curve provides an intuitive method to analyze the temperature change of a component in the whole reflow process. This is very useful for obtaining the best weldability, avoiding damage to components due to overtemperature, and ensuring welding quality.

Advantages:

1. When welding with flow welding technology, the parts do not need to be immersed in molten solder, but local heating is used to complete the welding task; Therefore, the welded components are subject to small thermal shock and will not be damaged due to overheating.

2. Because the soldering technology only needs to place solder at the welding position and complete the welding by local heating, the welding defects such as bridging are avoided.

3. In reflow soldering technology, the solder is only used once, and there is no reuse. Therefore, the solder is very clean and free of impurities, which ensures the quality of solder joints.