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 come to understand with you-let's go!
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、Specifications for PCB circuit board control
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 date of manufacture, please bake it at 120±5°C for 1 hour;
(2) If the PCB board is more than 2 months after the date of manufacture, please bake it at 120±5°C for 1 hour before going online;
(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°C before going online. Baking at ±5C for 4 hours;
(5) The baked PCB must be used within 5 days (put into lRREFLOW), and it needs to be baked for 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 laid flat, and the maximum number of stacks is 30 pieces; open the oven within 10 minutes after baking, take out the PCB and place it flat to cool naturally (requires a pressure-proof board bay fixture)
(2) Small and medium-sized circuit boards (including 8 PORTs below 8 PORTs) are placed flat and placed in a stack of up to 40 pieces, and the number of vertical ones is not limited. Open the oven and take out the PCB within 10 minutes after baking. 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. In March and April every year, there will be "back to the south" weather. It was raining and it was very humid at this time. The PCB must be used up within 24 hours after being exposed to the air, otherwise it will be easily oxidized. It is best to use it up 8 hours after normal opening. For some PCBs that need to be baked, the baking time will be longer. In the northern region, the weather is generally dry, and the storage time of PCB will be longer and the baking time can 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, and it is necessary to make specific choices based on the production capabilities, processes, regions and seasons of different Shenzhen circuit board manufacturers on the basis of PCB control specifications.
