When we choose solder paste, we must first understand the basic characteristics of the components themselves, such as how high the temperature is, what is the material of the components, and what is the process of the components, etc., in order to select the appropriate tin The second is to consult the solder paste manufacturers about the advantages and disadvantages of each type of solder paste and the fields that can be applied, the peak temperature of the furnace recommended for the SMT process, etc., and the two Chilean solder manufacturers have detailed information in the previous article. Before introducing each type of solder paste, it should be explained that different manufacturers have different processes and formulas for producing solder paste, so we must pay attention to distinguishing them when purchasing solder paste. The following is the method of selecting and distinguishing low-temperature, medium-temperature, and high-temperature solder paste produced by the Chilean manufacturer:

1. Look at the packaging: Solder paste is generally available in bottles and syringes. The weight of a bottle is 500g. The packaging color of lead-free solder paste is generally green, and the color of the bottle of medium-temperature solder paste and low-temperature solder paste is light. The green, high-temperature solder paste bottles are markedly different in color.

2. Look at the label: the produced solder paste will have a detailed label before it is placed in the cold storage. We only need to look at the column of its alloy composition. The composition of low-temperature solder paste is SN/BI, and the composition of medium-temperature solder paste is SN , there is Ag in addition to BI; the main component of high-temperature solder paste is Sn/Ag/Cu, and 0307, 105, 305, etc. commonly used in the high-temperature solder paste industry refer to the ratio of tin, silver, and copper.

3. If you want to further distinguish whether it is low temperature, medium temperature or high temperature solder paste, you can use tools to test it. We can take a small amount of solder paste and use a constant temperature heating platform to do experiments, so as to distinguish it by the melting point range of each solder paste we introduced above. , In addition, it can also be tested with the help of a spectrometer. This method is the most accurate. It can accurately test the detailed components of the solder paste, and judge whether it is a low-temperature solder paste, a medium-temperature solder paste, or a high-temperature solder paste through the composition of the solder paste.