Solder resist layer in the control of PCBA soldering process during the role of welding defects is very important, PCB designers should minimize the spacing or air gap around the pad features. Inappropriate PCB solder resist design can lead to the following PCBA defects:

1. solder resist film is too thick than the thickness of the PCB copper foil pads, and then flow soldering will form a suspension bridge and open circuit. 2. solder resist processing and pad alignment is poor, which leads to contamination of the surface of the pad, resulting in poor solder joints eat tin or produce a large number of solder balls. 3. between two pads with wires through the PCB solder resist design should be taken to prevent soldering 4. when there are more than two close to the SMD, the pads share a common wire, the application of solder resistance to separate them, so as not to produce stress when the solder shrinkage SMD shift or pull crack.