As usual, paying attention to some details can eliminate unwanted situations, such as misprints of solder paste and removal of solidified solder paste from the board. Our goal is to deposit an appropriate amount of solder paste at the desired location. Dirty tools, dry solder paste, and misalignment between the template and the board can all cause unwanted solder paste on the bottom surface of the template or even on the assembly. During the printing process, wipe the template according to a certain pattern between printing cycles. Ensure that the template is located on the solder pad, not on the solder mask layer, to ensure a clean solder paste printing process. Online and real-time solder paste inspection and pre reflow inspection after component installation are both helpful process steps for reducing process defects before welding occurs. For fine-pitch templates, if the thin template cross-section is bent and causes damage between pins, it can cause solder paste to deposit between pins, resulting in printing defects and/or short circuits. Low viscosity solder paste may also cause printing defects. For example, high operating temperature or scraper speed of a printing machine can reduce the viscosity of solder paste during use, resulting in printing defects and bridging due to excessive deposition of solder paste. Overall, the lack of sufficient control over materials, methods and equipment for solder paste deposition are the main reasons for defects in reflow soldering processes. Using a small scraper to remove the solder paste from the mistakenly printed board may cause some problems. The generally feasible method is to immerse the mistakenly printed board in a compatible solvent, such as water with some additive, and then remove the small tin beads from the board with a soft bristled brush. I would rather soak and wash repeatedly than vigorously dry or scrape. The longer the operator waits to clean the misprint after solder paste printing, the harder it is to remove the solder paste. Misprinted boards should be immediately placed in a soaked solvent after discovering the problem, as the solder paste is easy to remove before drying. Avoid wiping with cloth strips to prevent solder paste and other pollutants from being applied to the surface of the board. After soaking, washing with a gentle spray can often help remove unwanted tin drafts. It is also recommended to use hot air drying. If a horizontal template cleaning machine is used, the surface to be cleaned should face downwards to allow the solder paste to fall off the board.