The process of soldering will allow you to make several printed circuit boards in a short time. So do you know the main types of soldering? In this passage we will lead you to the professional knowledge of PCB soldering. Please check and read for more information.
Dip Soldering vs. Wave Soldering
In simplest terms, dip soldering is a soldering process with limited scope. Just like wave soldering, it can be used both for surface mount and through-hole circuit board assemblies. Further, the solder rains over the bare metallic areas of the printed circuit board. Thus, you will observe a reliable electrical and mechanical connection. Finally, dip soldering is the manual version of the automatic soldering process.
Reflow Soldering vs. Wave Soldering
Reflow soldering is the most famous way of fixing surface mount components onto the printed circuit board. You will need to create a solder paste out of flux and solder powder. And then, you will use that paste to fix electronic components onto the contact pads. You will further heat the whole package under an infrared lamp or in a reflow oven. The solder will then liquefy and make connections between the joints.
On the other side, you can also solder different joints with a hot air pencil. Figure 4 shows the printed circuit board assembling moving into the reflow oven machine.
Now, you must be wondering which technique should be used and when? Generally, wave soldering is more complicated than reflow soldering. In wave soldering, the time for which the PCB stays in the solder wave and PCB temperature requires careful monitoring. The printed circuit board can be defective if the soldering environment is not right.
However, with reflow soldering, you don’t need to fret much about environment control. But with this being true, you must know that wave soldering is cheaper and faster than reflow soldering. In many applications, wave solder is the only useful way of soldering components onto the board.
You will notice that reflow is mostly used for small-scale applications. Such applications do not need reliable, cheap, and fast mass production of PCBs. Surprisingly, you can also use a combination of reflow and wave solder. You can solder components on one side with waves soldering and can use reflow soldering on the other side.
So, these are some alternatives to wave soldering. However, there is still another type of soldering technique that the next chapter compares with wave soldering.
Selective wave soldering
Selective Soldering Machine
What if you have sensitive parts that can get damaged in the wave solder process or reflow oven? What do you suggest should be done to avoid the high temperatures? Would you want to try your luck with wave soldering or reflow soldering? Or, would you wish for any other way? Well, fortunately, that is where the selective wave soldering comes in.
It would help if you went for selective soldering when you fear that your electronic components will not survive reflow or wave soldering. You will find a wide variety of particular wave solder machines in the market. There are nitrogen inserted standard machines, solder pot type machines, and many others. Figure 5 demonstrates the selective waves soldering machine.
Selective Wave Soldering Guidelines
When you buy a selective wave soldering machine, software and guidelines will come with them. Generally, you will need to do the following three steps to do work:
• You need to apply the liquid flux,
• You need to assemble the PCB or preheating,
• You need to solder using a “site-specific” solder nozzle.
Selective Soldering problems
In selective soldering, you can encounter the following problems:
1. Copper pad dissolution: High temperature can dissolve the copper pad into the molten solder.
2. Solder balling: Solder balls can be formed due to the sticking of the solder mask at high temperature.
3. Solder bridging: Excess solder can make an additional connection between two pins.
4. Solder Stringing: Solder remains across the solder nozzle can cause it.
Selective Wave Soldering Machine Cost
If you want to compare selective soldering machine with wave soldering machine cost, you will be pleased to know that selective soldering will be five times cheaper. It will be because of less electricity requirement, less flux and solder consumption, no cleaning, less rework, and no protective taping.
Hopefully, you can now decide about the soldering technique that you want to use. But before you make your final decision, we have also mentioned the defects, cost, and problems of waves soldering in the next chapter.