Doing this simplifies the manufacturing process and also prevents unwanted etching. The industrial method of manufacturing printed circuit boards uses strong solvents like sodium sulfate. Tinning will facilitate this since the risk of corrosion is much lower when a printed circuit board is tinned.
Also, the cost of placing copper traces with higher thickness levels on circuit boards with small current areas is much higher than usual. It is another reason why PCB tinning is preferable; it will save money, especially when there is a high existing path bridge.
What is the PCB tinning process?
How PCB tinning is performed?
As the name suggests, PBC tinning utilizes tin. The question is how this tin is used to mask the copper traces in a printed circuit board. The tinning process does indeed use pure tin. However, it also uses a soldered container, a mixture of lead and tin, mixed at a 60:40 ratio. Pure tin and soldered tin are what make up the base of the PCB tinning solution.
What is electroplating method of PCB tinning?
There are many ways to tin a printed circuit board physically, but the most common method is called the electroplating method. In this method, the circuit board is placed in a tin plating station. When this happens, the tin electrodes are introduced into the controlled current flow. It completes the first coating of soldered tin.
After the printed circuit board itself is entirely produced, the second coating of a tin can be applied. To create the second coating of tin, even more soldering must be done. The soldered layers of the container can be deposited either by hand or by a hot solder extruder, which will collect the soldered tin onto the area.
It will resemble liquid, which, if soldered correctly, will dry quickly as it is poured onto the copper trace. Like copper, the tin will also oxidize if exposed to outside environments. One of the reasons solder masking is applied is not to leave the circuit board unmasked.
Is PCB tinning necessary?
Recall that the entire purpose of PCB tinning is to prevent the copper materials in a printed circuit board from encountering corrosion if it is exposed to anything. Consider that any given printed circuit board will be exposed to some outside elements. PCB tinning will reduce the pressure from these external elements and impede the copper inside of the circuit board from oxidizing, if not halt it outright.
Some argue that PCB tinning is optional, and they would be correct. It is never a requirement for any given printed circuit board to be tinned. After all, it would operate the same without tinning as it would if it otherwise. The question, therefore, is one of longevity.
When a printed circuit board is tinned, it guarantees that the copper inside of the circuit board will last much longer. Additionally, PCB tinning will naturally enhance the current in the tracks of the circuit board and will allow it to operate and perform much more consistently.
A printed circuit board without any tinning can be compared to a house with an old and unstable roof. While the top will still protect from outside forces, it would not be nearly as effective as a brand new roof. PCB tinning will provide a “new roof” of sorts for the copper tracing inside of a circuit board.
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