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Jul.2020 20
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What effect will common solder pad have on PCB welding
Introduction
SMT pad design is a key part of PCB design. It determines the welding location of components on the PCB and plays a significant role in the reliability of solder joints, possible welding defects, clearness, testability and maintainability.If PCB pads are
Details
SMT pad design is a key part of PCB design. It determines the welding location of components on the PCB and plays a significant role in the reliability of solder joints, possible welding defects, clearness, testability and maintainability.If PCB pads are properly designed, a small amount of mount skew can be corrected during reflow due to the self-correcting effect of molten solder surface tension.On the contrary, if the DESIGN of PCB welding plate is not correct, even if the mounting position is very accurate, there will be components displacement, stele and other welding defects after reflow welding.Therefore, the design of solder pad is one of the key factors to determine the manufacturability of surface assembly components.Common solder pad is a common and frequent disease in PCB design, and it is also one of the main factors causing PCB welding quality hidden trouble.

1. After welding wafer type components on the same soldering pad, if the pin insert components or wiring is welded again, there is a hidden danger of virtual welding during secondary welding.

 

2. Limited the repair times of subsequent commissioning, testing and after-sales maintenance.

 

3. During maintenance, unsolder a component and all components around the pad are unsolder.

 

4. When the welding plate is in common use, the stress on the welding plate is too high, resulting in the stripping of the welding plate during welding.

 

5, the components are common between the same welding plate, too much tin, the surface tension after melting is asymmetric, pull the components to one side, resulting in displacement or stele.

 

6. Similar to the non-standard use of other welding pads, the main reason is that only circuit characteristics and area or space constraints are considered, leading to a lot of components installation and welding spot defects in the assembly and welding process, which ultimately has a great impact on the reliability of circuit work.