Why Do PCB Need to be Baked?

Due to the existence of water molecules in the air, if the PCB is exposed to the air for a long time, the external moisture may enter the PCB board, and the purpose of baking is to remove moisture, and evaporate the excess moisture in the PCB by heating.

If the content of water molecules in the PCB exceeds the relevant regulations, in the process of high temperature reflow soldering, wave soldering or hand soldering, these internal water molecules will be heated and atomized into water vapor will expand rapidly as temperature rises. The higher the temperature, the larger the atomization volume. When the water vapor cannot escape from the PCB in time, it is likely to expand the PCB, thereby breaking the via holes between the PCB layers, causing the separation of the layers of the PCB. In severe cases, blistering, expansion, and board explosion can be seen from the outside of the PCB.

Sometimes the above problems cannot be seen on the outside of the PCB, but in fact the inside of the PCB has been damaged, which will affect the stability of the product function over time and eventually lead to the failure of the product function.

So what should be paid attention to when baking PCB? The baking time needs to be set according to the thickness and size of the PCB; In order to avoid PCB bending during the cooling after baking, thinner or larger PCB need to be pressed against the board with a heavy object after baking. Because once the baked PCB is bent and deformed, there will be offset or uneven thickness when printing the solder paste on the SMT, which will also cause a large number of soldering short circuits or dry soldering defects to occur during the subsequent reflow.

HoYoGo is a international, professional and reliable PCB manufacturer with 2 PCB factory production bases, our production strictly follows the high quality system and has passed  ISO9001, ISO14001, ISO13485 and TS16949 and C-UL-S certification. All products strictly follow the acceptance criteria of IPC-A-600-H and IPC-6012.