Why does lead-free solder paste become thinner and thinner the more it is scraped? What causes it?

Why?Lead-free solder pasteWhy is it getting thinner the more you scrape? This question has also been asked by many people and is quite perplexing. Some people say it's due to poor product quality or incorrect usage. We all know that lead-free solder paste has certain flow characteristics. When we increase the stirring speed of the solder paste and the time it takes, its viscosity will also decrease. People can also call it "flash solubility". In this case, what causes it? Now, let's talk about this situation from JJY solder Paste Manufacturer:

During the use of solder paste, if its viscosity increases or even dries out, it can cause many problems, such as poor printing, missed printing, reduced solder discharge, device displacement, and flying chips, all of which can lead to a significant decline in the solder yield. There are many reasons why solder paste becomes thinner and thinner as it is scraped. Generally speaking, they can be attributed to the usage conditions and the quality of the solder paste. However, essentially, it is all caused by the chemical reaction between the flux and the solder powder.

There are three types of viscosity changes in lead-free solder paste during the printing process:

1The viscosity increases----On the contrary, if the solvent in the formula is highly volatile, it will become drier the more it is scraped

2The viscosity decreases----If the solvent volatility in the solder paste manufacturer's flux formula is relatively weak, it will become thinner and thinner the more it is scraped.

3The viscosity first decreases and then increases (with very small slopes) and remains stable----This phenomenon should be an ideal situation, that is, the proportion of each component of the flux is just right.

The above is13With years of industry experience, Shenzhen JJY Industrial Technology Co., LTD., which has accumulated experience, ensures more outstanding welding results. We hope this answer can inspire you. If you want to know more aboutSMTFor other issues regarding solder paste in surface mount technology, partners are welcome to come and consult.