PCB Technical - PCBA baking conditions and specifications

PCBA baking conditions and specifications

1. PCBA baking instructions:
For devices that are no longer used after repair, in principle, PCBA components are not baked and dehumidified, but if the entire board needs to be heated to 110°C or higher during the repair process, or if there are other moisture-sensitive devices within 0.5cm around the repair work area, PCBA components must be pre-baked and dehumidified according to the requirements of moisture sensitivity and storage conditions. If the PCBA contains plug-in electrolytic capacitors, it must be baked in a convection oven at low temperature. If there is no plug-in electrolytic capacitor, high temperature baking can be used.

2. PCBA baking conditions
At the same time, for moisture-sensitive devices that are reused after repair, if hot air reflow, infrared, etc. are used to heat the solder joints through the device package, the PCBA components must be baked at low temperature according to the moisture sensitivity level and storage conditions of the repaired device. ; For the rework process that uses a manual soldering iron to heat the solder joints, under the premise that the heating process is controlled, there is no need to pre-bake the moisture-sensitive devices.

PCBA and device rework heating times require different PCBA components and devices for cumulative rework heating times. The number of rework heating allowed for the same number of PCBA components is no more than 4; the number of rework heating allowed for the device is no more than 5 times. If the number of rework heating is exceeded, the reliability of the components and devices has dropped sharply. It is not recommended to re-send it to the customer, but it can be used for test purposes.

When PCBA is double-sided SMT reflow soldering, when the time difference between the first and second sides production exceeds the unpacking service life of the humidity sensitive component on the first side, the PCBA that completes the first side SMT must be baked before continuing SMT production on the second side.

3. PCBA baking requirements:
1. First check whether the temperature and humidity of the material storage are within the required range every shift every day (feed back and deal with any abnormalities in time).
2. Untrained personnel are forbidden to work on their posts.
3. If there is any abnormality during the operation, notify the engineering and technical personnel in time.
4. Electrostatic protection must be done when touching materials, and electrostatic gloves must be worn.
5. Lead and lead-free materials need to be stored and baked separately.
6. After the baking is completed, wait for the components and materials to cool down to room temperature before they can be vacuum packaged or used online.

Four, attached: PCBA baking precautions:
1. You must wear gloves when touching PCBA.
2. Do not bake over time.
3. The baked PCAB must be cooled to room temperature before going online.
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