Proper storage is crucial for the quality and reliability of PCBs. Temperature and humidity control, anti-static measures, appropriate storage methods, and regular inspections can effectively extend the service life of PCBs.
Reasonable storage not only helps improve the reliability of products, but also provides a solid guarantee for subsequent production and assembly.
1. Environmental humidity control
Humidity is one of the key factors affecting PCB storage.
High humidity environments can easily cause oxidation on the surface of PCBs, which in turn affects electrical performance and soldering quality.
Especially during the assembly process of PCB circuit boards, humid environments may lead to poor soldering or short circuits, thereby affecting the functionality of the entire circuit board.
Therefore, the storage environment for PCBs should be maintained between 50% -60% relative humidity.
Usually, anti-static aluminum foil bags are used to package PCBs, and desiccants are used to absorb moisture.
These measures can effectively prevent PCB from being affected by moisture during storage and maintain its long-term stability.
2. Temperature control
Temperature also has a significant impact on the quality of PCBs.
Excessive storage temperature may cause aging of PCB materials, especially some plastic substrates and packaging materials that may expand or deform due to high temperatures, thereby affecting the reliability of circuit boards.
The storage temperature of PCB should be kept within the normal temperature range (about 20-25 ℃) and should not exceed 40 ℃.
In addition, excessive temperature fluctuations may also lead to thermal expansion and contraction of PCBs during storage, which can have a negative impact on the mechanical stability and soldering reliability of PCBs.
3. Anti static measures
Static electricity is one of the common causes of PCB damage, especially for sensitive components and circuits.
Electrostatic discharge (ESD) may damage semiconductor components on circuit boards, resulting in decreased performance or complete failure.
Anti static materials such as anti-static bags, ESD cartons, etc. should be used for packaging to avoid the accumulation of static electricity and discharge damage to PCBs. Operators should also wear anti-static wristbands or anti-static clothing when handling PCBs.
4. Storage location and placement method
The storage location and placement of PCBs have a direct impact on their storage conditions.
During storage, PCBs should avoid direct contact with the ground to prevent the accumulation of dust, moisture, and other pollutants.
It is usually recommended to place PCBs on dry and clean shelves, and avoid stacking them too high or too many to prevent PCB deformation or damage due to heavy pressure or external forces. At the same time, the storage area should be away from strong light exposure, high temperature sources, chemicals, and pollution sources.
5. Storage time and regular inspection
The storage time of PCB should not be too long, as long-term storage may lead to surface oxidation, poor soldering, or performance degradation.
Usually, the storage period is controlled, and it is recommended to use PCBs within 6 months after storage to ensure their quality.
If long-term storage is required due to special reasons, the PCB should be inspected regularly to confirm its status and promptly address any possible damage.
6. Special storage requirements
Some special types of PCBs, such as high-frequency PCBs, flexible PCBs, HDI PCBs (high-density interconnect boards), etc., may have different storage conditions from regular PCBs.
For example, flexible PCBs should avoid excessive bending or severe impact during storage due to their soft material, in order to avoid damaging the circuit.
High frequency PCBs require special attention to temperature and humidity control to prevent changes in the dielectric properties of the material.
In addition, for PCBs with special processes or advanced applications, special environmental conditions such as low-temperature storage and nitrogen protection may be required to maintain their long-term stability and high performance.
