Why does solder paste need to be stirred before use?

Solder paste, as an indispensable solder material in the electronics industry, is often used by electronics manufacturers. When purchasing solder paste, the solder paste manufacturer will remind the producer that the solder paste needs to be stirred before use. Why? Today, the solder paste manufacturer will take you through why it is necessary to stir before use:

I. Why Stir

This brings us to the composition of solder paste. Solder paste is a paste-like mixture formed by mixing solder powder, flux, and other surfactants and thixotropic agents. It is accompanied bysmtThe new soldering materials produced by the surface mount technology are an important factor in ensuring the reliability of the reflow soldering process. The flux contains different components, such as rosin, active agents, thickeners, etc. When these substances are left to stand for a long time, due to their own gravity, they will sink and cause sedimentation and stratification, which will seriously affect the function of the solder paste. Therefore, it is necessary to stir it before use. Remix these substances together for use. Since solder paste needs to be frozen during storage, its fluidity and uniformity will be affected. Therefore, before printing, solder paste should be thoroughly stirred to ensure that the flux and solder powder are evenly mixed, so as to achieve a good application effect. The general stirring time is1～4The minutes vary depending on the stirring method.

Ii. Why is it Necessary to warm up in Advance

This is because solder paste needs to be stored at low temperatures5-10Refrigerate at a certain temperature. Take the solder paste out of the refrigerator, keep the bottle cap sealed, and place it at room temperature2-4Hours,Let its temperature balance with room temperature, and then open the bottle cap. And avoid having multiple bottles of solder paste closely arranged during the warming process. If they are arranged too closely, the contact area with the environment will be reduced, which will affect the warming effect.

The solder paste just taken out of the refrigerator will be at a lower temperature than the ambient temperature. If it is opened and used directly, the temperature difference can easily absorb moisture from the air and adhere to the surface of the solder paste. During the reflow soldering process, if the solder paste contains moisture, it will cause poor soldering, leading to cracked beads and the formation of solder beads. So before use, the solder paste should not be opened and should be placed indoors2-4When the temperature is low, warm it up to make the temperature of the solder paste consistent with the ambient temperature.

Shenzhen JJY Industrial Technology Co., Ltd. is located in Longhua, Shenzhen. It mainly produces and operates lead-free solder paste, lead-free high-temperature solder paste, lead-free medium-temperature solder paste, lead-free low-temperature solder paste, etc. If necessary, please feel free to contact us.