How does PCBA processing control quality?

Viasion it is a PCBA foundry manufacturer that provides PCB board manufacturing, component purchasing, SMT chip processing, DIP plug-in processing, PCBA testing one-stop service. Next, how do you control the quality of PCBA processing?

There are many links involved in the PCBA manufacturing process. It is necessary to control the quality of each link to produce good products. The general PCBA is made up of: PCB circuit board manufacturing, component procurement and inspection, SMT chip processing, plug-in processing, Program firing, testing, aging and other processes, below we carefully explain where each link needs attention.

1. PCB circuit board manufacturing

After receiving the order from PCBA, analyze the Gerber file, pay attention to the relationship between the hole pitch of the PCB and the bearing capacity of the board, and do not cause bending or breakage. Whether the wiring takes into account the key factors such as high-frequency signal interference and impedance.

2.component procurement and inspection

Procurement of components requires strict control of channels, and must be picked up from large traders and original factories, 100% to avoid second-hand materials and fake materials. In addition, special inspection inspection positions are set up, and the following items are strictly checked to ensure that the components are fault free.

PCB: reflow soldering furnace temperature test, no flying line, no hole blocking or leaking ink, whether the board surface is bent, etc.;

IC: Check whether the silk screen and the BOM are exactly the same, and do the constant temperature and humidity preservation;

Other common materials: check screen printing, appearance, power measurement, etc. The inspection items are carried out according to the sampling method, and the ratio is generally 1-3%.

3.SMT Assembly processing

Solder paste printing and reflow soldering furnace temperature control are key points. It is very important to use laser steel mesh with good quality and meet process requirements. According to the requirements of the PCB, some need to increase or decrease the steel mesh, or use U-shaped holes to make steel mesh according to the process requirements. Reflow soldering furnace temperature and speed control is critical to solder paste infiltration and soldering reliability, and can be controlled in accordance with normal SOP operating guidelines. In addition, AOI testing needs to be strictly implemented to minimize the adverse effects caused by human factors.

4.DIP plug-in processing

In the plug-in process, the mold design for over-wave soldering is a key point. How to use the mold can maximize the probability of providing good quality after the furnace, which is a process that PE engineers must constantly practice and summarize.

5.Program firing

In the previous DFM report, customers can be advised to set up some Test Points on the PCB in order to test the PCB and the PCBA circuit continuity after soldering all components. If you have the conditions, you can ask the customer to provide a program to burn the program to the main control IC through the burner (such as ST-LINK, J-LINK, etc.), so that you can test the various touch actions more intuitively. Functional changes to verify the functional integrity of the entire PCBA.

6.PCBA board test

For orders with PCBA test requirements, the main test contents include ICT  FCT, Burn In Test , temperature and humidity test, drop test, etc., according to the customer's test plan. And summarize the report data.