PCB baking quality and PCB data operation process
Compare PCB baking
PCB baking can eliminate the internal stress of PCB, that is, stabilize the size of PCB. The warpage of the baking sheet was greatly improved.
Advantages of baking: After baking, the moisture in the pad can be dried to further enhance the welding effect and reduce the rate of faulty welding and repair.
Disadvantages of baking: The color of PCB may change, thus affecting the appearance.
The OSP process usually has a shelf life of 6 months after packaging. If this date is exceeded, it is basICally necessary to return to the PCB manufacturer for rework. If the baking temperature is usually 100-120 ℃, the baking time is about 2 hours, do not bake too long! It must be used up within 24 hours after being exposed to air, otherwise oxidation is likely to occur (depending on the manufacturing capacity of the supplier, some OSPs can be used for a longer time, and should be used up within 8 hours after normal unpacking).
Baking method and preservation method of PCB
Circuit board

–145； ※ Large circuit boards (16 ports and above, including 16 ports) are placed in one plane type and stacked with 30 pieces. Open the oven and take out the PCB to cool within 10 minutes of baking.
– μ SMAll and medium-sized PCB (8PORT and below 8PORT) are placed horizontally There are 40 pieces in a pile, and the number of vertical types is unlimited Open the oven within 10 minutes of baking, take out the PCB, lay it flat and cool it naturally
The specific storage time and baking temperature of PCB are not only related to the production capacity and production process of PCB manufacturers, but also have a great relationship with regions.
PCB made by OSP oxidation resistance process and pure gold leaching process usually has a shelf life of 6 months after packaging. Baking during OSP is generally not recommended.
The storage and baking time of PCB is closely related to the area. In the south, humidity is usually more effective, especially in Guangdong and Guangxi, where the weather of "returning to the south" occurs in March and April every year., It rains every day. It's very wet at this time. PCB must be used up within 24 hours when exposed to air, otherwise it is easy to oxidize. After normal opening, it is better to use it within 8 hours. For some PCBs that must be baked, the baking time will be longer. In the north, the weather is usually more dry than efficiency, the storage time of circuit boards will be longer, and the baking time can be shorter. The baking temperature is usually 120 ± 5 ℃, and the baking time is determined according to the specific situation.
For PCB storage time, baking time and temperature, specific problems must be analyzed in detail, and specific choices must be made according to the production capacity, technology, region and season of different circuit board manufacturers and PCB management and control specifications.
Material operation process in polychlorinated biphenyl production
PCBA production and processing plant has clear regulations on how to operate and use the "data operation program" in the production process. The purpose is to better implement the quality standards for data use, use data correctly and timely within the validity period, ensure the storage environment and quality of data, and prevent a series of quality problems in products.
Material operation process standards in PCBA production:
1. The Quality Assurance Department shall specify the validity period of each batch of incoming raw materials according to relevant standards.
2. The warehouse manager prints material labels (indicating product name, serial number, specification/quality standard, and incoming materials) in the ERP system according to the production date of the incoming materials, the qualification seal issued by the quality inspection department, and the company's internal use validity. Quantity, current quantity, production date, use effective date, effective date). The re inspection date is usually the first week of the month when the effective date is used.
3. The warehouse manager shall check the validity of the inventory data at the beginning of each month, and notify the Quality Assurance Department of the data that are close to the validity and reach the re inspection date.
4. For the expired raw materials, the warehouse manager shall fill in the re inspection form in time, notify the quality inspection department to re inspect them, and replace them with yellow status signs.
5. After receiving the re inspection notice from the warehouse manager, the Quality Inspection Department shall timely arrange the re inspection and issue the inspection report.
6. The Quality Assurance Department shall grant a time limit for the materials that pass the re inspection, and stipulate that they shall be used up within a time limit; For the materials that cannot be used up, the Purchasing Department shall negotiate with the supplier to replace them, otherwise the warehouse manager will ask the Quality Assurance Department to apply for the quality of the nonconforming products.
7. Nonconforming materials shall be treated as nonconforming products.
8. SMT solder paste shall be used within 6 months after the production date Solder pastes beyond the expiration date will be regarded as unqualified products The steps are the same as those for nonconforming products