PCB Technical - Stacking method during PCB baking

When baking large-size PCBs, use a horizontal stacking arrangement. It is recommended that the maximum number of a stack should not exceed 30. The oven needs to be opened within 10 minutes after the baking is completed to take out the PCB and lay it flat to cool it down. Bend fixture. Large-size PCBs are not recommended for vertical baking, as they are easy to bend.

When baking small and medium-sized PCBs, they can be placed in a flat stack. The maximum number of a stack is recommended not to exceed 40. It can also be upright. The number is not limited. You need to open the oven to remove the PCB and place it flat within 10 minutes after the baking is completed. After cooling and baking, it is necessary to press the anti-bending jig.
Precautions when PCB baking

1. The baking temperature should not exceed the Tg point of the PCB, and the general requirement should not exceed 125°C. In the early days, the Tg point of some lead-containing PCBs was relatively low, and now the Tg of lead-free PCBs is mostly above 150°C.

2. The baked PCB should be used up as soon as possible. If it is not used up, it should be vacuum packed as soon as possible. If exposed to the workshop for too long, it must be baked again.

3. Remember to install ventilation drying equipment in the oven, otherwise the steam will stay in the oven and increase its relative humidity, which is not good for PCB dehumidification.

4. From a quality point of view, the more fresh PCB solder is used, the better the quality will be. Even if the expired PCB is used after baking, there will still be a certain quality risk.