How do you know which type of soldering to use and when? It may depend on a variety of factors, such as pad shapes, the amount of time you have, component orientations, type of printed circuit board and more. In some ways, wave soldering is more complex. Issues like board temperature and time the board spends in the solder wave need careful monitoring. Failure to create the right wave soldering environment is much more likely to lead to board defects.
You don’t need to be nearly as concerned about controlling the environment when you’re utilizing reflow soldering to fabricate your printed circuit boards. However, even with that being the case, wave soldering tends to be faster and cheaper than reflow soldering. In more than a few cases, it’s the only practical way to solder a board. Reflow soldering is typically used in smaller-scale manufacturing products that don’t require a method amenable to fast, cheap mass production.
Keep in mind that you may be able to use both reflow soldering and wave soldering for certain situations. You might reflow solder parts on one side and then wave solder them on the other. Also, you can always manually solder or hand solder PCB components, but this will rarely be a good approach if you have access to one of the mechanical methods of soldering. Manual soldering would only be an alternative to reflow soldering, but reflow soldering is still far superior.
What are the differences of reflow soldering and wave soldering？
We can never ignore the difference between reflow soldering and wave soldering because it is important when you are selecting the PCBA services. A soldering modification tends to make drastic changes in the entire assembly manufacturing process. These include manufacturing cost, time to market, efficiency, and gains, etc.
The main difference between reflow soldering and wave soldering in terms of the manufacturing process is the flux spraying step. Wave soldering involves this step while the reflow soldering doesn’t. We use flux for promoting the soldering process. It helps by playing a protective role by eliminating the surface tension and reducing the surface tension. Flux only works when we activate it which we can only achieve by intensive time and temperature control. In reflow soldering, flux is present in the solder paste. Therefore, we need to appropriately arrange and achieve the required flux content.
Generally, wave soldering works best for DIP and THT while reflow soldering is ideal for SMT assemblies. However, a circuit board rarely contains only through-hole components or surface mounted devices. That is why we often have to use a mixture of SMT, THT, and DIP. When it comes to mixed assemblies, we first carry out SMT and then focus on DIP or THT. This is because the temperature of reflow soldering is much higher than the one in wave soldering. If we don’t follow this sequence then the solder paste might melt again. This can lead to well-soldered components to fall from the board or suffer from defects.
We use wave soldering mainly for mass production. It helps in manufacturing a large number of printed circuit boards in a relatively small amount of time.
On the other hand, we use reflow soldering when we have to manufacture a small number of printed circuit boards. We avail of this technique when we don’t have very tight time constraints.