There are many ways to detect true and false FR4 epoxy panels on the Internet. Almost all of them are identical in appearance, burning and other methods. I’m going to teach you a method of immersion testing today. Are you very interested? Then then look down.
FR4 epoxy board has good moisture resistance and non absorbent properties. Its water absorption is: water absorbency (D-24/23, plate thickness 1.6mm): less than 19mg. Even long soaking does not absorb much moisture. There will be no deformation, delamination and so on. And the size stability performance is still very good. You can record the appearance and performance before and after immersion, and take a picture. In contrast, there is no big difference.
This method can be used to detect the quality of FR4 epoxy board fundamentally. The quality of FR4 epoxy board can not be detected by fabrication. If there is no significant change in appearance before and after immersion, the quality should be no problem, on the contrary, Zhongtian reminds buyers that they need to buy carefully.