Solder pasteWhat could be the reason for the drying after two hours of printing? Some customers have reported to merchants that in many cases, after two hours of printing, the printing becomes dry, and some are very thick. So, what causes these problems? The checked situation is: The temperature is25.6°Humidity is27%Some people also inquired about the newly placed solder paste, which was also hung up. Many people don't know what the problem is when they encounter this situation. Now, JJY solder Paste Manufacturer will explain to you the situations that can lead to this situation. Let's take a look:

First, let's understand the reasons why solder paste dries out:

1The activity of the solder paste in the solder paste is released more vigorously at room temperature. The solder paste has already reacted with the solder powder. After the reaction, the solder paste becomes sticky and dry, and eventually may even form a lump.

2When using solder paste, the opened solder paste must be applied within the specified time. If it is reused repeatedly or not sealed properly after use, the solder paste will also dry out.

3During the process of reconfiguring solder paste, if the solvent is not chosen properly and there is too much volatile solvent, it can also cause the solder paste to dry out.

Note and Change:

Solder paste quality

Instability caused by solder paste design flaws, mainly among whichFLUXThe design and stability are also one of the main reasons for the dryness of solder paste.        Solder paste is made by mixing solder powder and flux. Therefore, the quality of the solder powder and the stability of the flux will both affect the service life of the solder paste. Among them, the stability of the flux is the key factor determining whether the solder paste dries out easily. The main function of solder paste is to remove the oxides on the surface of solder and solder joints. This is a chemical reaction process. For solder paste to play this role, it must be active. The active system of solder paste is the key to the smooth progress of welding. The stronger the activity, the stronger the ability to remove oxides; conversely, it is weaker. Due to its activity, the reaction between solder paste and tin powder always exists during storage and use. However, the reaction rate is very slow at low temperatures, but it occurs rapidly at the soldering temperature. Therefore, the reaction rate between solder paste and solder powder at room temperature determines the service life of the solder paste

A well-designed solder paste and flux active system must simultaneously meet two conditions: it should have strong activity at the soldering temperature to complete the soldering, and at the same time remain inert at room temperature. To achieve this goal, the active groups must be specially treated so that they do not show activity at room temperature but can rapidly release activity when the temperature rises to a certain extent. Solder paste that dries easily often has active groups in the active system that are relatively active at room temperature. Therefore, during printing, with the introduction of water vapor and oxygen, the reaction speed between the solder paste and the solder powder is accelerated, causing it to dry out. 

Temperature and humidity during use

The storage temperature of solder paste is2-10℃However, when in use, the recommended ambient temperature is20-25℃The relative humidity is30%-60%Because every time the temperature rises10℃The speed of the chemical reaction will double. Therefore, if the temperature is too high, it will increase the evaporation rate of the solvent in the solder paste, andFLUXThe reaction speed with tin powder thus leads to the solder paste being prone to drying out. Excessive humidity, on the other hand, will significantly increase the amount of moisture entering the solder paste and also affect the evaporation rate of the solvent in the solder paste.       

Although excessively high temperatures can cause the solder paste to dry out, we should not use temperatures that are too low either. Temperatures that are too low will affect the viscosity and extensibility of the solder paste, which may lead to poor printing results.

This is some solder paste knowledge I want to share with you all. You can modify and check your own situation based on the current circumstances and conditions to make adjustments. Well, I hope this article can be of some help to you. If you still have any questions, welcome to consult Shenzhen JJY Industrial Technology Co., LTD. Let's learn and grow together! Solder wire of JJY brandSolder pasteSolder rods, always looking forward to your companions coming to take them away together.