With the development of higher density, smaller size, and more complex PCB hybrid technology for electronic assembly, the inspection of post-print quality with the naked eye is a thing of the past.Despite more advanced process equipment, there is an emphasis on strict quality control of PCBs, as 70% of defects generated during electronic assembly originate from the solder paste printing process, especially when depositing finer pitch components.In addition, defects such as missing printing, too much or too little solder produced in the process of depositing solder paste will bring bridges, short circuits and tombstone phenomena to the subsequent process (component placement), which makes the quality and reliability of the final product produced.Therefore, people pay more and more attention to the inspection of solder paste after printing.