PCB Tech - Introduction to the preservation and baking time of PCB in blind and buried circuit board factory

Friends in the PCB industry know that after the completion of the PCB, there is a shelf life. If the shelf life is exceeded, the PCB must be baked, otherwise the PCB will be prone to bursting when it is produced on the smt line.

The storage time of PCB in blind and buried via circuit board factory and the temperature and time of baking PCB are all regulated by the industry. What is this specification, let's look at it together.

1, PCB management and control specifications

1. PCB unpacking and storage
   (1) Sealed and unopened, if the manufacturing date is within 2 months, it can be directly used online
   (2) The manufacturing date is within 2 months, and the unpacking date must be marked after unpacking
   (3) The manufacturing date is within 2 months, and it must be online and used within 5 days after unpacking

   
   

   2, PCB baking
   (1) If sealed and unpacked for more than 5 days within 2 months of the date of manufacture, bake at 120±5°C for 1 hour
   (2) 2 months after the manufacturing date, baking at 120±5 degree Celsius for 1 hour before going online
   (3) 2 to 6 months after the manufacturing date, baking at 120±5 degree Celsius for 2 hours before going online
   (4) 6 to 12 months after the date of manufacture, baking at 120±5°C for 4 hours before going online
   (5) PCBs that have been baked must be used up within 5 days (put into IR REFLOW), and unused PCBs must be baked for another hour before they can be used online.
   (6) One year after the manufacturing date, baking at 120±5 degree Celsius for 4 hours before going online, and then sending it to the PCB factory for re-spraying tin before going online.

3, PCB baking method

(1) Large PCBs (16 PORTs and above, including 16 PORTs) are placed horizontally, with a maximum of 30 pieces in a stack. Open the oven within 10 minutes after the baking is completed, and take out the PCB and place it horizontally to cool down (need to press the anti-plate bay fixture)
(2) Small and medium-sized PCBs (including 8PORTs below 8PORT) are placed horizontally, with a maximum of 40 pieces in a stack, and the number of upright types is not limited. Open the oven within 10 minutes after the baking is completed. Banwan fixture)

2. The preservation and baking of PCBs in different regions by the blind buried via circuit board factory

The specific storage time and baking temperature of PCB are not only related to the production capacity and production process of the PCB manufacturer, but also have a great relationship with the region.

The PCB made by OSP process and pure immersion gold process has a shelf life of 6 months after packaging. It is generally not recommended to bake for OSP process.

The storage and baking time of PCBs in blind buried via circuit board factories has a lot to do with the region. The southern part is humid, especially in areas such as Guangdong and Guangxi. In March and April of each year, there will be "returning to the south". The weather, rainy and rainy, is very humid. PCB exposed to the air must be used up within 24 hours, otherwise it is easy to oxidize. After normal opening, it is best to use it up in 8 hours. For some PCBs that need to be baked, the baking time will be longer. In the northern regions, the weather is generally dry, the PCB storage time will be longer, and the baking time can also be shorter. The baking temperature is generally 120±5 degree Celsius, and the baking time is determined according to the specific situation.