The conformal coating should be tested for product qualification before selection. For the printed circuit board conformal coating, there are already mature product specifications in the industry, which can be tested according to these specifications to evaluate whether it meets the requirements of the product standard. The commonly used standards mainly include, the electronic industry standard SJ20671-1998, and the American International Electronic Connection Association standard IPC-CC-830B.These standards all stipulate the classification of three anti-paints, the technical indicators of various performance indicators,requirements, relevant test methods and acceptance requirements, etc.
When conformal coating certification is required, it is usually necessary to test various performance parameter indicators. In actual evaluation, it can be appropriately selected or increased according to the specific application requirements of the enterprise products. These parameters include the liquid properties of the coating and the properties after film formation. When the performance test of the coating film is carried out, the quality of the film-forming sample will directly affect the test results of the film performance.Therefore,in addition to ensuring the smoothness and thickness of the coating film, appropriate dry film thickness is also a very important factor influencing uniformity and no bubbles.
Through the performance parameter test of the conformal coating materials,the quality can be initially determined. However, from the failure of many printed circuit board assemblies that implement three-proof protection, there are many failures due to corrosion or cracking which caused by mismatching between the conformal coatings and other materials. Therefore, the company should fully evaluate the compatibility of the conformal coating with PCB boards, components, and other auxiliary materials used in the process.
There are many kinds of conformal coatings, and some of them are not good. Only after strict testand optimization, can you select coating materials with good protection performance and suitable for your own products and processes, thus improving product reliability.
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