1. For solder powder detection, the particle size of tin powder can be measured with a high magnification microscope to check the distribution of tin powder particles. It is relatively high, which proves that the quality of this solder paste
solder powder is relatively good, and it will not affect the quality of SMD printing on the stencil.
2. Use atomic absorption spectrometer to measure the chemical elements in the solder paste. Usually the detection items are the content of harmful metal elements such as lead, mercury and cadmium. If the solder paste is a halogen-free solder paste, it is also necessary to check the halogen in the solder paste in advance. Does the content meet the standard?
3. In the viscosity test, the viscosity of the solder paste will greatly affect the printability of the solder paste on the screen. If the viscosity of a solder paste is large, the slump performance will be greatly improved, but the printability will be poor. It may affect the release effect, and the solder paste may stick to the stainless steel mesh, resulting in poor printing.
4. Stencil printability test, the use of smt stencil to print solder paste is an indispensable step in the patch welding process, so it is essential for a solder paste to have good printability, so the IQ C department can Take a small amount of solder paste and perform a printability test to verify that the stencil printability of this solder paste is good.
5. Test the solderability of the solder hook. The sweatability of the solder paste can be divided into wettability and solderability. This function is mainly to test whether the solder paste will dry out. If it does not dry out, the connection strength after soldering meets the requirements. requirements? This step of checking whether it is good or bad can be tested using discarded circuit boards and electronic components that have been disassembled.
6. Whether the solder joints are full and shiny, this detection step can be done by pasting the solder paste on the glass and reflow soldering. After the soldering is completed, it can be observed with the naked eye to see whether the solder joints are shiny. It can also be seen from the glass whether there is a lot of residue after solder paste soldering?
Through the above steps, we can basically judge the quality of a solder paste intuitively or from data, whether the solder paste is lead, lead-free or silver-containing, an experienced electronics factory can pass each The data of each test is summarized and organized into a table, and the quality of the solder paste is verified by analyzing the results of each test.