The ineffective solder joints in PCBA processing are due to poor positioning of electronic components, poor quality of soldering flux, unqualified residue, and air oxidation; Another way to control quality is to submit a manufacturability report (DFM) based on different customer needs. Next, let me introduce the detailed content to you.

1、 Why are solder joints ineffective in PCBA processing

1. Poor positioning of electronic components: coating, environmental pollution, air oxidation, and common spots.

2. Poor PCB solder layer: coating, environmental pollution, air oxidation, shrinkage and expansion.

3. Disadvantages of welding material quality: composition, unqualified residue, air oxidation.

4. Disadvantages of soldering flux quality: low solderability, high corrosion resistance, low SIR.

6. Disadvantages of other auxiliary materials: adhesives, cleaning agents.

2、 How to Control Quality in PCBA Processing

1. It is particularly important to hold a pre production meeting after receiving orders to process PCBA. It mainly analyzes the process of PCBGerber files and submits a manufacturability report (DFM) according to different customer requirements. Many small manufacturers do not take this seriously. But this is often the case. It is not only prone to quality issues due to poor PCB design, but also requires a significant amount of rework and repair work.

2. Procurement and inspection of electronic components provided by PCBA

The procurement channels for electronic components must be strictly controlled, and goods must be obtained from large traders and original manufacturers to avoid the use of second-hand and counterfeit materials. In addition, it is necessary to establish a dedicated PCBA feed inspection station to strictly inspect the following items to ensure that the components are fault free.

PCB: Check the temperature test of the reflow oven, whether the through holes without flying wires are blocked or leaking, and whether the board surface is bent.

IC: Check if screen printing is exactly the same as screen printing. BOM， And store it under constant temperature and humidity.

3. SMT assembly

The solder paste printing and reflow oven temperature control system are key points in assembly and require laser templates with higher quality and processing requirements. According to the needs of PCB, some require the addition or reduction of steel wire mesh or U-shaped holes, and only the steel wire mesh needs to be made according to the process requirements. Among them, the temperature control of the reflow soldering furnace is very important for the wetting of the solder paste and the firmness of the steel wire mesh, and can be adjusted according to the normal SOP operation guide. In addition, strict implementation of AOI testing can greatly reduce defects caused by human factors.

4. Plugin processing

During the plugin process, the mold design for wave soldering is crucial. PE engineers must continue to practice and summarize how to use molds to maximize productivity.

5. PCBA processing board testing

For orders with PCBA testing requirements, the main testing contents include ICT (circuit testing), FCT (functional testing), combustion testing (aging testing), temperature and humidity testing, drop testing, etc.