After the PCB circuit board is manufactured, it will have a shelf life. After this shelf life, the PCB board needs to be baked. Otherwise, it is easy to cause the problem of PCB explosion when the PCB board is put into production in the SMT workshop. Below, the editor of Shenzhen Senyan Circuit Board Factory will take a look with you!
The storage time of PCB boards, as well as the temperature and time of baking PCB boards in industrial ovens are all industry-standard.
一、PCB circuit board management and control specifications
1. PCB unpacking and storage
(1) PCB boards can be used directly online within 2 months of the sealed and unopened manufacturing date;
(2) PCB boards are manufactured within 2 months, and the unpacking date must be marked after unpacking;
(3) The manufacturing date of the PCB board is within 2 months, and it must be used online within 5 days after unpacking.
2. PCB board baking
(1) If the PCB board is sealed and unpacked for more than 5 days within 2 months of the manufacturing date, please bake it at 120 ± 5°C for 1 hour;
(2) If the PCB board is more than 2 months after the manufacturing date, please bake it at 120°C before going online. Baking at ±5°C for 1 hour;
(3) If the PCB board is 2 to 6 months beyond the date of manufacture, please bake it at 120±5°C for 2 hours before going online;
(4) If the PCB board is 6 months to 1 year past the date of manufacture, please bake it at 120±5°C before going online. Bake at 5°C for 4 hours;
(5) The baked PCB must be used within 5 days (put into IRREFLOW), and it needs to be baked for another 1 hour before it can be used online;
(6) If the PCB is more than 1 year old from the manufacturing date, please bake it at 120±5°C for 4 hours before going online, and then send it to the PCB factory for re-spray tin before going online.
3. PCB baking method
(1) Large-scale circuit boards (16 PORTs and above including 16 PORTs) are placed flat, with a maximum of 30 pieces in a stack. Open the oven within 10 minutes after baking and take out the PCB.
(2) Small and medium-sized circuit boards (including 8 PORTs below 8 PORTs) are placed flat. The maximum number of stacks is 40 pieces, and the number of vertical ones is not limited. Open the oven and take out the PCB within 10 minutes after baking. Anti-banwan fixture)
二、Preservation and baking of circuit boards in different regions
The specific storage time and baking temperature of PCB circuit boards are not only related to the production capacity and production process of PCB manufacturers, but also have a great relationship with the region.
PCBs made by OSP anti-oxidation process and pure immersion gold process generally have a shelf life of 6 months after packaging, and baking is generally not recommended for OSP processes.
The storage and baking time of PCB circuit boards have a great relationship with the region. In the south, the humidity is generally heavy, especially in Guangdong and Guangxi, where there will be "back to the south" weather in March and April every year. It rains continuously every day, and it is very humid at this time. The PCB must be used up within 24 hours after being exposed to the air, or it will be easily oxidized. After normal opening, it is best to use it up within 8 hours. For some PCBs that need to be baked, the baking time will be longer. In the northern region, the weather is generally drier, and the storage time of PCB will be longer. The baking time can also be shorter. The baking temperature is generally 120±5℃, and the baking time is determined according to the specific situation.
For the storage time, baking time and temperature of PCB boards, specific problems need to be analyzed in detail. On the basis of PCB control specifications, specific choices should be made according to the production capabilities, processes, regions and seasons of different Shenzhen circuit board manufacturers.
