PCBA storage conditions and requirements at different stages
2023-12-04
PCBA production process needs to go through several storage stages, after the completion of SMT patch processing into DIP plug-in processing, before the plug-in processing, often need to store a certain amount of time, PCBA board testing is completed, after the assembly of the finished product, often have a period of storage time, then, What are the conditions and requirements of PCBA storage at different stages?
1. Store SMT patches after processing
Under normal circumstances, after the SMT patch processing is completed, it will be placed in the DIP workshop for 1-3 days, sometimes longer. For ordinary types of boards, the temperature is controlled between 22-30 ° C, the humidity is controlled between 30-60%RH, and it is placed on the anti-static rack. However, for the PCB board of the OSP process, it needs to be kept in the constant temperature and humidity cabinet, the temperature and humidity requirements are more stringent, and the welding is completed within 24 hours as far as possible, otherwise the welding pad is easy to oxidize.
2. Storage after PCBA test is completed
In general, PCBA board after the completion of the test, the finished product assembly will be relatively fast, in this case, the temperature and humidity control is good, not too big requirements. However, if you need to store for a long time, you can apply three anti-paint, and vacuum packaging, the ambient temperature is controlled between 22-28 ° C, and the relative humidity is 30-60%RH.
| Type | Appearance | Storage Condition | Storage Period |
| Spray tin | The finish is silver | 1. Temperature :22+4C 2.Humidity:30%-60%RH 3. Vacuum packaging (containing desiccant) |
12 months |
| Immersion Gold | The finish is gold | 1.Temperature:22+4C 2. Humidity :30%-60%RH 3. Vacuum packaging (containing desiccant) |
6 months |
| Immersion tin | The finish is silver | 1. Temperature: 22+4C 2. Humidity :30%-60%RH 3. Vacuum packing (containing desiccant) |
3 months |
| Immersion Ag | The finish is silver | 1. Temperature: 22+4C 2. Humidity :30%-60%RH 3. Vacuum packaging (containing desiccant) |
3 months |
| OSP | The finish is gold | 1. Temperature: 22+4C 2. Humidity :30%-60%RH 3. Straight packaging (containing desiccant) |
3 months |
Under normal circumstances, the storage life of PCBA processed products is 2 to 10 years, mainly affected by the following factors:
1. The environment
Wet, dusty environment is obviously not conducive to the preservation of PCBA, these factors will accelerate the oxidation of PCBA, dirty, shorten the shelf life of PCBA. In general, it is recommended that PCBA be stored in a dry, dust-free space at a constant temperature of 25 degrees Celsius.
2. Reliability of components
The reliability of components on different PCBA also largely determines the storage period of PCBA, and the components of high-quality materials and processes have the ability to resist harsh environments, with a wider range of capabilities and stronger oxidation resistance, which also provides protection for the stability of PCBA.
3, circuit board material and surface treatment process
The material of the circuit board itself is extremely vulnerable to environmental effects, but its surface treatment process is greatly affected by air oxidation. The surface treatment of good process can extend the shelf life of PCBA.
4. PCBA board running load
PCBA operating load is the most important factor in its preservation period, the operation of high frequency and high load, itself on the circuit board lines and components will have a sustained high impact, affected by heat more easily oxidized, resulting in short circuit and open circuit phenomenon during long-term operation. Therefore, the operating parameters of the PCBA board should preferably be in the middle value range of the components and avoid being near the peak value, which can effectively protect the PCBA and extend its storage life.
The storage life of PCBA processed products is a comprehensive work, which needs to follow scientific design specifications, production process specifications and operation specifications, so as to extend its storage life to the greatest extent. Under normal circumstances, PCBA board spraying three anti-paint can extend the shelf life of 3-9 months, but some PCBA board is not suitable for coating three anti-paint, need to be determined according to the actual situation of the product.
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