Storage time of different surface treatment processes for circuit boards

王者荣耀2

Storage time of different surface treatment processes for circuit boards [Copy link]

Because copper is easily oxidized in the air, the copper oxide layer has a great influence on welding, and it is easy to form false welding and virtual welding. In severe cases, it will cause the pad and the components to be unable to be welded. Therefore, when manufacturing, Jiepei will have a process to coat (plating) a layer of material on the surface of the pad to protect the pad from oxidation. The surface treatment process of PCB is different, and their shelf life is also different. 1. Considering the differences in product process and storage conditions, the printed board should be used in time (recommended within 24 hours) after unpacking, and it is recommended to pre-dry it before use, especially the PI substrate board in the flexible circuit board. If patch welding is required, it must be pre-dried.

2. For chemical immersion tin or immersion silver products, it is recommended to use them within 12 hours after unpacking, otherwise they must be repacked.

3. If the effective shelf life is exceeded, the user can try it out after drying: if necessary, some performance tests must be carried out again, and they can still be used after passing the inspection.

4. Usually, if the storage time exceeds 3 months, it is necessary to bake at 150 degrees for 2 hours before mounting on the machine to avoid the hidden danger of moisture.

Storage environment:

A. Good storage conditions: refers to indoor environmental conditions with a temperature of less than 25 degrees, a relative humidity of no more than 65%, temperature control, and no corrosive gases. B. General storage conditions: refers to the indoor environment conditions with a temperature not higher than 35 degrees, a relative humidity not higher than 75%, and no corrosive gases.

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Require the PCB manufacturer to indicate the validity period on the certificate after leaving the factory.

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It seems that the PCB does not indicate whether it is a self-made request or whether the PCB factory issues the certificate itself?