False plating is caused by plating fixture problems or power problems, and the metal (such as nickel) on the surface of the PCB is replaced by metal ions in the plating cylinder, and the result of false plating is poor adhesion, or even a wash with water. Drag cylinder is a daily measure taken when the metal and non-metal impurities in the plating cylinder increase after the plating cylinder has been working for a period of time. Generally, a corrugated metal sheet is used to electroplate the plating cylinder with a small current for a period of time, which can purify the plating solution to a certain extent.