The causes and solutions of "monument erection" in SMT assembly processing

inSMTDuring surface mount technology (SMT) processing, there is sometimes a phenomenon where the ends of components are lifted up, known as a "monument", which affects the quality and performance of the product. The fundamental cause of this "monument" is the imbalance of wetting forces at both ends of the component, resulting in an imbalance of torque at both ends and causing the component to tilt. The following is Shenzhen JJYSolder paste manufacturerThe reasons for the appearance of the shared monument and the corresponding solutions:

I. Analysis of the Causes of Monument Erection

1The load-bearing capacity at both ends of the components is uneven, and the tin content is inconsistent.

2The preheating temperature is unreasonable and the preheating temperature rise rate is too fast.

3Machine mounting offset, poor mounting accuracy, and severe component offset;

4The thickness of the solder paste printing is uneven, the printing accuracy is poor, and the misalignment is severe.

5Improper setting of furnace temperature, either too high or too low;

6The nozzle is severely worn and the position is misaligned during mounting.

7Oxidation of the soldering coating at both ends of the component pins causes the solder paste to have different wetting forces. When two different wetting forces are generated, wetting deviation or stmonument formation will occur.

Ii. Corresponding Handling measures

1When opening the steel mesh, make the two ends of the welding pad equal.

2Adjust the preheating and heating rate to makepcbThe plates meet the corresponding temperature requirements in each temperature zone.

3Adjust the machine mounting offset, debug in time to avoid hardware problems;

4Adjust the position of the printing press;

5Adjust the temperature of the reflow oven:

6ReplaceOKSuction nozzle

7When conditions permit, timely replacement of the oxidized material at the pins can reduce the occurrence of adverse situations. If the materials are not replaced, the defects should be reduced in time by optimizing the furnace temperature curve or replacing the solder paste with strong soldering ability.

As a 16-year-old veteran solder paste manufacturer, JJY has been committed to the research and development, production and sales of solder paste. Our product quality is stable, with no solder connection, no false soldering, and no monument erection. Residual Wuxi beads, bright and full solder joints, firm welding, and excellent electrical conductivity. If you have any needs, please feel free to contact us.