Before the patch processing in Xi ‘an SMT small batch patch processing factory, there is a process that is not particularly noticed, that is, baking. Some circuit boards in the electronics factory that don’t meet the requirements of Xi ‘an SMT chip processing due to long storage time and humidity in the storage environment can get rid of excess moisture after reasonable baking process, which is beneficial to the processing quality and makes SMT chip components and pads better combined together. Generally, PCB must be baked only if it has been washed. Otherwise, too many times of baking will cause blistering of the board. However, generally, the original PCB will have a humidity card. First, make sure whether the humidity exceeds the standard. Sometimes, even if there is a drying bag inside, it will get damp, so it must be baked.
Precautions of baking board before SMT small batch SMD processing factory in Xi ‘an.
1. Requirements: The temperature is 120 5℃, and it is usually baked for 2 hours. Time is counted from the time when the temperature reaches the baking temperature. For specific parameters, please refer to the corresponding baking specifications of circuit boards.
Second, the temperature and time:
1. If the manufacturing date is 2 to 6 months, bake at 120 5℃ for 2 hours.
2. If the manufacturing date is 6 months to 1 year, bake at 120 5℃ for 4 hours.
3. If the manufacturing date is more than 5 days after the sealing and unpacking within 2 months, bake at 120 5℃ for 1 hour.
4. The circuit board that is greater than the manufacturing date for 1 year can be baked at 120 5℃ for 4 hours, and then sprayed with tin again.
5. The baked circuit board must be processed within 5 days, and the unfinished circuit board needs to be baked for another hour before it can be put on line.
III. Processing methods:
1. The components that will not be used after repair need not be baked.
2. Small and medium-sized circuit boards are mostly placed horizontally, and 40 boards can be stacked. There is no limit to the number of vertical boards. Take them out of the oven within 10 minutes after baking, and put them horizontally at room temperature to cool naturally.
3. Large and medium-sized circuit boards in SMT small batch SMD processing plants are mostly placed horizontally, and 30 boards can be stacked. After baking, they can be taken out of the oven within 10 minutes, and then placed horizontally at room temperature for natural cooling.