What are the storage time and usage methods of solder paste?

The storage time and usage method of solder paste are what manufacturers using solder paste must know. When we cooperate with new cooperative manufacturers, we will always give them a copySolder pasteThe usage specification manual clearly states the shelf life and usage precautions of the solder paste. Now, the solder paste manufacturer will provide a detailed explanation and analysis for everyone:

The characteristics of the solder paste itself

First, the characteristics of the solder paste itself should be considered. Solder paste is made by mixing solder powder, flux paste and some other additives. Therefore, the quality of the solder powder and the stability of the flux paste will both affect the service life of the solder paste. After the solder paste is produced, it is generally stored2-10℃Store in the refrigerator and bring it back to a warm temperature before use20-25℃Relative humidity30%-60%. Because every time the temperature rises10℃The chemical reaction rate will double. Therefore, if the temperature is too high, it will cause the solvent in the solder paste to evaporate and accelerate the reaction between the flux and the solder powder, thereby drying out the solder paste. If the temperature is too low, it will affect the viscosity and expansion of the solder paste, which is likely to cause poor printing.

The influence of the external environment

Secondly, the influence of the external environment should be taken into account. Under normal circumstances, unopened solder paste is at room temperature after being warmed up22-25℃It can be placed below.5About a day. If the solder paste is warmed up and stirred before printing begins, it is generally at24Good soldering effect can be maintained within hours. Therefore, it is recommended to use up the solder paste that has been warmed up on the same day. If there is any remaining solder paste, when using it the next day, first use the newly opened solder paste, and mix the remaining solder paste from the previous day with the new solder paste1:2The proportion Mix and stir, and add in small amounts and multiple times for use. It is recommended that after the solder paste is printed on the substrate,4-6Complete the surface mount components and reflow soldering within hours; otherwise, poor soldering or solder paste drying may occur. Solder paste has a shelf life and can be stored in the refrigerator6For months, if it exceeds6If it is used for a month, its performance will change. Generally, it is not recommended to use it.

The reactions of solder paste during storage and use

Finally, it should be known that solder paste undergoes chemical reactions during both storage and use. Although this kind of reaction is inevitable, a well-designed solder paste should have a very slow reaction speed under normal usage conditions, which can meet the normal production requirements. If the solder paste dries out easily, it is often due to flaws in the formula design. In addition, ensuring a usage environment that meets the requirements and standardized operation can also extend the service life of solder paste. Other factors such as the evaporation of solvents during use can also affect the service life, but they are not the main factors. From the above points, we can clearly know how long solder paste can be kept outside and what to pay attention to when placing or storing it. To make solder paste achieve good soldering results, it is necessary to pay attention to controlling the environmental temperature, humidity and sealing in time, etc.

JJY Solder Paste Factory produces a wide range of solder paste products, including lead-free solder paste, halogen-free solder paste, silver-containing lead solder paste, syringe solder paste, environmentally friendly solder wire, nickel-plated environmentally friendly solder wire, silver-containing environmentally friendly solder wire, lead-free solder bars, high-temperature solder bars, etc. We can provide technical support. If you have any needs or technical questions regarding soldering, please feel free to leave a message online to interact with us!