The PCBA manufacturing process involves many links. The quality of each link must be controlled to produce a good product. The general PCBA is made up of: PCB circuit board manufacturing, component procurement and inspection, SMT patch processing, plug-in processing, A series of processes such as program firing, testing, and aging, the following Dongguan PCBA processing plant will carefully explain the points that need to be paid attention to in each link.
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 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 faults
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 Assembly processing
Solder paste printing and reflow oven temperature control are key points, and it is very important to use laser stencils of good quality and meeting process requirements. According to the requirements of the PCB, some need to increase or reduce the steel mesh, or use U-shaped holes to make the steel mesh according to the process requirements. The temperature and speed control of the reflow soldering furnace is critical to the solder paste infiltration and soldering reliability, and 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. Plug-in processing
In the plug-in process, the mold design for wave soldering is a key point. How to use the mold 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 (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, and burn the program into the main control IC through a burner (such as ST-LINK, J-LINK, etc.), so that you can more intuitively test the effects of various touch actions Functional changes to verify the functional integrity of the entire PCBA.
6. PCBA board test
For orders with PCBA test requirements, the main test content includes ICT (In Circuit Test), FCT (Function Test), Burn In Test (aging test), temperature and humidity test, drop test, etc., according to the customer’s test plan. And summarize the report data.
