Wave soldering is suitable for mass production of circuit boards with low requirement. Selective soldering focuses on high precision PCBs, which cannot be completed by common wave soldering machine. Selective wave soldering machine can improve the welding quality, but the production efficiency is relatively low. Both kinds of soldering machine are complementary and play an irreplaceable role in production. In mass production, if the requirements for welding quality are not high, wave soldering machine is recommended. Selective wave soldering machine can be used in small batch production with high welding quality.
In the past, there was no other effective method to deal with PCB with mixed components except manual welding. However, manual point-to-point welding for PCB needs more labors and the efficiency was low. With selective wave soldering machine, we can adopt assembly line for bath production and use welding nozzle with different size, and the welding efficiency can be improved dozens of times than that of manual welding. Selective soldering can precisely control each solder joint by programming, with repeatable operation, which is more stable than manual soldering and soldering robot and more controllable in temperature, process, welding parameters and so on. It can also avoid some fixed screw and reinforcing rib on the bottom of PCB by program setting, so as to avoid damage caused by contact with high temperature solder. It is suitable for through-hole welding products which are becoming smaller and denser.
The biggest difference between the two soldering ways is that the traditional wave soldering is to immerse the whole welding side of PCB into the solder, while selective wave soldering only solder selective parts. The selected welding mode will do flux spraying first, then preheat, and then weld. Compared with traditional wave soldering, the flux is also selectively spraying to the parts that need soldering, not the whole PCB. In the soldering process, the position of the solder head is fixed, and PCB is moved to all directions.
The advantages of selective wave soldering: smaller footprint, flux saving, few solder dross, nitrogen saving, less fixture and even no fixture. In addition, it has less smoke generation, the start-up power is lower than traditional wave soldering, more energy-saving and environmental protection, higher welding quality, and greatly reduces the maintenance cost.
In short, the parameter of selective wave soldering is easier to quantify than traditional wave soldering, and the defect rate is controllable. It is suitable for the production of with complex products and high quality requirements. For this kind of product is expensive and profitable, that is to say, it can not only make up for the shortcomings of wave soldering quality, but also make profit. The combination of these two equipment can achieve a better balance of production efficiency and quality.