Share~The little secret of PCB protective coating
Conformal coating is necessary for PCBs and PCBAs that must work in harsh environments. It can protect the circuit board from erosion, moisture and dust, and extend the shelf life of electronic products to ensure the performance and reliability of electronic products. Today, the editor will take everyone to take a look at the protective effect of conformal layer on PCB.
For harsh environments, conformal coatings should be optimized to better adapt to extreme environments. The following protective measures should be technically optimized: conformal coating shielding, static elimination and film thickness measurement.
Now, some parts of the PCB that do not need conformal coating should be covered, so that unnecessary parts (such as circuit board brackets, potentiometers, switches, power resistors, connectors) will not be sprayed with conformal coatings. The stop signal is abnormal. In the implementation of conformal coating, masking tape is usually used for conformal coating shielding. In order to meet the different shapes of different components in the shield, the shielding tape is cut into different shapes and sizes. Due to its shortcomings, this method is prone to quality problems, including low efficiency, static electricity generation, and excessive gel residue that is difficult to eliminate.
Optimization measures
3M tape should replace traditional tape. The cutting method should be from tool cutting to the use of special cutting tools, because special cutting tools can determine and cut different shapes according to the shape, volume and size of the shield. As long as the protective cover is covered with unnecessary parts, it will not be sprayed with a conformal coating.
Conformal coating thickness measurement
The surface of the PCB adopts a conformal coating, which is a thin and light film with a thickness of only a few microns. This kind of film can effectively isolate the surface of the circuit board from the environment and prevent the circuit from being corroded by chemicals, moisture and other contaminants. Therefore, the reliability of the circuit board will be greatly improved, the safety factor will be strengthened, and the shelf life will be guaranteed for a long time. However, due to the unevenness of the coating, the protective function of the conformal coating is still unclear. Therefore, both the PCB and the final product will fail, especially in harsh environments.
How to maintain long-term stable performance in harsh environments is a very important issue in the manufacture and application of electronic components. Therefore, technicians must take necessary protective measures to ensure the normal operation of electronic products in harsh environments. Therefore, the methods and methods described above are very important, and they are also common conformal layers.
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