With the continuous development of electronic technology, people’s requirements for product design are getting higher and higher, engineering wiring is becoming more and more precise, and electronic component application packaging is getting smaller and smaller. Product quality control has become the biggest challenge for PCB assembly. From PCB circuit board manufacturing, component procurement and inspection, SMT chip processing, plug-in processing, program firing, testing, aging and other processing to the final product shipment, each step is very important, and any details in the assembly process will determine the quality of the final product.
1. PCB Circuit Board Manufacturing
After receiving the PCBA order, analyze the Gerber file, pay attention to the relationship between the PCB hole spacing and the board’s load-bearing capacity, do not cause bending or breakage, and whether the wiring considers key factors such as high-frequency signal interference and impedance.
2. Procurement and Inspection of Components
The procurement of components requires strict control of channels, and must be picked up from large traders and original factories, and 100% avoid second-hand materials and fake materials. In addition, a special inspection post for incoming materials is set up, and the following items are strictly inspected to ensure that the components are free of failure.
- PCB: Reflow soldering furnace temperature test, no flying leads, whether the vias are blocked or leaking ink, whether the board surface is bent, etc.;
- IC: Check whether the silk screen is completely consistent with the BOM, and keep it at constant temperature and humidity;
- Other common materials: Check the silk screen, appearance, power-on measurement, etc. The inspection items are carried out according to the random inspection method, and the ratio is generally 1-3%.
3. SMT Patch Processing
Solder paste printing and reflow oven temperature control are key points. It is very important to use laser stencils of good quality and meeting process requirements. According to the requirements of PCB, some steel mesh holes need to be enlarged or reduced, or U-shaped holes are used to make steel mesh according to process requirements. The furnace temperature and speed control of the reflow soldering is very critical to the solder paste infiltration and soldering reliability. It can be controlled in accordance with the normal SOP operation guidelines. In addition, AOI testing needs to be strictly implemented to minimize the defects caused by human factors.
4. DIP Plug-In Processing
In the plug-in process, the mold design for wave soldering is a key point. How to use molds to maximize the probability of good products after the furnace is a process that PE engineers must continue to practice and summarize experience.
5. Program Firing
In the previous DFM report, customers can be suggested to set up some test points on the PCB, the purpose is to test the PCB and PCBA circuit continuity after soldering all components. If you have conditions, you can ask the customer to provide a program, burn the program into the main control IC through the burner, and test the function changes brought about by various touch actions more intuitively, so as to test the function of the entire PCBA completeness.
6. PCBA Board Test
For orders with PCBA test requirements, the main test content includes ICT, FCT, aging test, temperature and humidity test, drop test, etc., according to the customer’s test plan operation and summary report data.
PHILIFAST provides one-stop PCB manufacturing and assembly services, complete production process, and focus on quality control.
