PCBA welding process mainly refers to the production process of welding PCB circuit boards prototype and components through soldering process. During the welding process, poor welding such as virtual welding and false welding are prone to occur. Virtual welding and false welding will seriously affect the reliability of the product and greatly increase the maintenance cost of the product.
The problem of virtual soldering and false soldering defects in PCBA welding processing is caused by many reasons, mainly because the solder cannot fully infiltrate the pads and component pins, and the components and the circuit board pads cannot be fully welded. In the production process, it can be prevented in the following ways.
1. Moisture-proof storage of components
If the components are placed in the air for too long, it will cause the components to absorb moisture and oxidize the components, which will cause the components to not fully remove the oxides during the welding process, resulting in defects such as virtual soldering and false soldering. Therefore, during the soldering process, the components with moisture should be baked and the oxidized components should be replaced. Generally, the PCBA processing factory will be equipped with an oven to bake the components with water vapor.
2. Use well-known brands of solder paste
False soldering and false soldering defects that occur during PCBA soldering have a lot to do with the quality of solder paste. The unreasonable configuration of alloy metal components and flux in the solder paste composition will easily lead to weak activation of the flux during the soldering process, and the solder paste cannot fully infiltrate the pad, resulting in false soldering and false soldering defects. Therefore, you can choose solder paste from well-known brands such as Senju, Alpha, and Victaulic.
3. Adjust printing parameters
The problem of virtual soldering and false soldering is largely due to the lack of tin. During the printing process, the pressure of the scraper should be adjusted, and a suitable stencil should be selected. The opening of the stencil should not be too small to avoid the situation of too little tin.
4. Adjust the reflow soldering temperature curve
When performing the reflow soldering process, it is necessary to control the soldering time. If the time in the preheating zone is not enough, the flux cannot be fully activated and the surface oxide on the soldering place can be removed. If the time in the soldering zone is too long or too short, it will cause virtual Welding and false welding.
5. Try to use reflow soldering to reduce manual soldering
Generally, when using an electric soldering iron for manual soldering, the technical requirements for the soldering personnel are relatively high. If the temperature of the soldering iron tip is too high or too low or the soldered components become loose during soldering, it is easy to cause false soldering and false soldering. Use reflow Welding can reduce artificial external factors and improve the quality of welding.
6. Avoid the temperature of the electric soldering iron being too high or low
In the post-welding processing and maintenance of PCBA welding, it is necessary to use electric soldering iron for manual welding. When using an electric soldering iron, non-standard operation will lead to the temperature of the soldering iron head being too high or too low, which will easily cause false soldering and false soldering. Therefore, when soldering, keep the tip of the soldering iron clean, choose different power types of soldering irons according to the size of different components and solder joints, and device shapes, and control the soldering temperature between 300°C and 360°C.
False soldering and false soldering caused during the PCBA welding process are caused by many factors. The above are just some of the more common reasons. Through the above preventive measures, combined with the actual situation, the virtual soldering can be effectively reduced. And false welding welding defects are gone. Dataifeng has BGA rework station, placement machine, X-RAY import pointing machine, heating platform and other supporting equipment. The main products are all kinds of chip refurbishment IC cleaning and plating feet, CPU DDR EMMC, ball planting rework and refurbishment IC tape processing, professional bga chip processing IC processing ball planting bead welding BGA rework engineering PCB board SMT patch proofing, etc.
How to prevent common false soldering and virtual soldering defects in PCBA soldering
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