What are the disadvantages of solder mask?

One of the main disadvantages of solder mask is that it can increase the overall cost of PCB production. The material itself is relatively expensive, and the additional step required to apply it to the circuit board can add additional time and labor costs to the manufacturing process. Additionally, if the solder mask is not applied correctly, it can lead to defects in the PCB that can be costly to fix.

Another potential disadvantage of solder mask is that it can be difficult to repair. If a PCB needs to be reworked or repaired, the solder mask can make it more difficult to access and work with the underlying copper traces. This can increase the cost of repairs and make it more time consuming for technicians to fix any issues.

Solder mask also has the potential to introduce additional thermal stress to the circuit board. The process of applying the solder mask involves exposing the board to high temperatures, and this can cause additional stress on the underlying components. While this is not typically a major issue, it is something that manufacturers need to keep in mind when designing and producing circuit boards.