PCB SMT Patch Processing Should The Factors Of Quality

In the process of SMT patch processing, special attention should be paid to the factors of processing quality

SMT patch processing is a complex process, including many links, and welding is one of the important links. The quality of welding will determine the quality of the product. If there is a mistake, it will directly affect the quality of patch processing. The circuit board is unqualified or even scrapped. Therefore, special attention should be paid in the process of SMT chip processing, and good welding habits should be developed to avoid affecting the quality of chip processing due to improper welding. So what are the bad welding methods in SMT chip processing?

1. The process of welding the heating bridge is not appropriate. Soldering thermal bridge in SMT chip processing is to prevent solder from forming a bridge. If this process is not operated properly, it will lead to cold solder joints or insufficient solder flow. Therefore, the correct soldering habit should be to place the tip of the soldering iron between the pad and the pin, and the tin wire is close to the tip of the soldering iron. When the tin is melted, move the tin wire to the opposite side, or place the tin wire between the pad and the pin. , The soldering iron is placed on the tin wire, and the tin wire is moved to the opposite side when the tin is melted; in this way, good solder joints can be produced to avoid affecting the SMT processing.

2. During SMT chip processing, excessive force is applied to the soldering of the pins. Many workers in SMT chip processing factories think that excessive force can promote the heat conduction of solder paste and promote the soldering effect, so they are used to pressing down hard when soldering. In fact, this is a bad habit, which can easily lead to problems such as lifting, delamination, depression, and PCB white spot on the pad of the patch. Therefore, it is completely unnecessary to use too much force during the soldering process. In order to ensure the quality of the patch processing, it is only necessary to gently touch the soldering iron tip to the pad.

3. Improper transfer welding operation. Transfer welding means that the solder is first added to the soldering iron tip , and then transferred to the connection. Improper transfer soldering can damage the tip and cause poor wetting. Therefore, the normal transfer welding method should be to place the tip of the soldering iron between the pad and the pin, the tin wire is close to the tip of the soldering iron, and move the tin wire to the opposite side when the tin is melted. Place the tin wire between the pad and the pin. Place the soldering iron on the tin wire, and move the tin wire to the opposite side when the tin melts.

4. Randomly choose the tip of the soldering iron without considering the appropriate size. In the process of patch processing, the size selection of the soldering iron tip is very important. If the size of the soldering iron tip is too small, the residence time of the soldering iron tip will be prolonged, which will cause insufficient solder flow and lead to cold solder joints. An oversized tip can cause the joint to heat up too quickly and burn the patch. Therefore, the selection of the appropriate soldering iron tip size should be based on the three criteria of correct length and shape, correct heat capacity and maximizing the contact surface but slightly smaller than the pad.

5. The temperature setting is incorrect. Temperature is also an important factor in the soldering process. If the temperature is set too high, it will cause the pad to lift, the solder will be overheated and the circuit patch will be damaged. Therefore, setting the correct temperature is particularly important for the quality assurance of chip processing.

6. Improper use of flux. It is understood that many workers are used to using too much flux in the process of patch processing. In fact, this not only cannot help you have a good solder joint, but also causes the problem of whether the solder leg is reliable, and it is easy to cause corrosion. , electron transfer and other issues.

SMT chip processing is currently the most commonly used surface mount technology in the electronics industry. Correctly mastering the chip processing method and avoiding the appearance of bad welding methods can not only improve product quality and speed up work efficiency, but also avoid unnecessary waste and loss. save costs.