The PCBAprocessing process involves many links, and it is necessary to control thequality of each link to produce a good product. The general PCBA is composedof: PCB circuit board manufacturing, component procurement and inspection, SMTpatch processing, plug-in processing, A series of processes such as programburning, testing, aging, etc. Below we carefully explain the points that needto be paid attention to in each link.

1. PCB circuitboard manufacturing

After receivingthe PCBA order, analyze the Gerber file, pay attention to the relationshipbetween the PCB hole spacing and the bearing capacity of the board, do notcause bending or breaking, and whether the wiring considers key factors such ashigh-frequency signal interference and impedance.

2. Componentprocurement and inspection

The procurement ofcomponents requires strict control of channels, and it is necessary to pick upgoods from large traders and original factories, and 100% avoid second-handmaterials and fake materials. In addition, set up special incoming inspectionpositions, strictly check the following items to ensure that the components arenot faulty.

PCB: temperaturetest of reflow soldering furnace, prohibition of flying wire, whether the holeis blocked or ink leakage, whether the board surface is bent, etc.;

IC: Check whetherthe silk screen is completely consistent with BOM, and keep it at constanttemperature and humidity;

Other commonmaterials: check the silk screen, appearance, power-on measurement, etc. Theinspection items are carried out according to the random inspection method, andthe proportion is generally 1-3%.

3. SMT Assemblyprocessing

Solder pasteprinting and reflow soldering furnace temperature control are the key points.It is very important to use laser stencil with good quality and meet theprocess requirements. According to the requirements of PCB, some need toincrease or decrease the steel mesh hole, or use U-shaped hole, according tothe process requirements to make steel mesh. The furnace temperature and speedcontrol of reflow soldering is critical to solder paste infiltration andsoldering reliability, and can be controlled according to normal SOP operationguidelines. In addition, AOI testing needs to be strictly implemented tominimize the adverse effects caused by human factors.

4. DIP plug-inprocessing

In the plug-inprocess, the mold design for wave soldering is the key point. How to use themold can maximize the probability of providing good products after the furnace,which is a process that PE engineers must constantly practice and sum upexperience.

5. Program burning

In the previousDFM report, customers can be suggested to set some test points on the PCB (TestPoints), the purpose is to test the PCB and PCBA circuit continuity aftersoldering all components. If you have the conditions, you can ask the customerto provide a program, burn the program into the main control IC through aburner (such as ST-LINK, J-LINK, etc.), you can more intuitively test thevarious touch actions brought by Functional changes to test the functionalintegrity of the entire PCBA.

6. PCBA board test

For orders withPCBA 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 operation And summarizethe report data.