Borey Advanced - Some Common Poor Welding Habits in SMT SMT Chip Placement Machine Processing

2023-11-01


In the SMT chip processing process, welding is an indispensable and important link. Any batch leakage during the welding process will directly affect the unqualified or even scrapped circuit board of the chip processing. So in the process of SMT chip processing, special attention should be paid to appropriate welding habits to avoid affecting the quality of chip processing due to improper welding

 

 

 

 

1: The process of welding the heating bridge is not appropriate. The welding thermal bridge in SMT processing prevents the formation of bridging of solder. If this process is not operated properly, it can lead to insufficient flow of cold solder joints or solder. So the correct welding habit should be to place the soldering iron head between the soldering pad and the pin, with the tin wire close to the soldering iron head. When the tin is melted, move the tin wire to the opposite side, or place the tin wire between the soldering pad and the pin, with the soldering iron placed on top of the tin wire. When the tin is melted, move the tin wire to the opposite side; Only in this way can good solder joints be produced to avoid affecting the chip processing.

2: Improper transfer welding operation. Place the tin wire between the solder pad and the pin. Improper transfer welding can damage the soldering iron head and cause poor wetting. Transfer welding refers to adding solder to the soldering iron head before transferring it to the connection. So the normal transfer welding method should be to place the soldering iron head between the soldering pad and the pin, with the tin wire close to the soldering iron head, and move the tin wire to the opposite side when the tin melts. Place the soldering iron on top of the tin wire and move it to the opposite side when the tin is melted.

3: Improper use of soldering flux. It is understood that many workers are accustomed to using too much soldering flux during the SMT process. In fact, this not only does not help you have a good solder joint, but also causes issues such as the reliability of the lower solder joint, which can easily lead to corrosion, electron transfer, and other issues.


4: During SMT processing, excessive welding force is applied to the pins. Many SMT processing workers believe that excessive force can promote the heat conduction of solder paste and promote the soldering effect, so they are accustomed to pressing down with force during welding. In fact, this is a bad habit that can easily lead to problems such as warping, layering, depression, and PCB white spots on the solder pads of the SMD. So it is completely unnecessary to exert too much force during the welding process. To ensure the quality of SMT processing, simply lightly touch the soldering iron head with the solder pad.

five Randomly selecting a soldering iron head, without considering the appropriate size. In the process of SMD processing, the size selection of the soldering iron head is very important. If the size of the soldering iron head is too small, it will prolong the retention time of the soldering iron head, causing insufficient solder flow and resulting in cold solder joints. If the size of the soldering iron head is too large, it will cause the connection to heat up too quickly and * * * * * the SMD. Therefore, when selecting a suitable soldering iron head size, it is necessary to use the correct length and shape, and the correct heat Choose between the three criteria of capacity and making the contact surface smaller but slightly smaller than the solder pad.

6: Unnecessary modifications or rework. So never make unnecessary modifications or rework to the patch. And this approach not only cannot improve the quality of the patch, but also can easily cause the metal layer of the patch to fracture, PCB delamination, waste unnecessary time, and even cause scrap. The taboo in the welding process of SMT processing is to modify or rework in pursuit of perfection.