The nylon powder used for coating the magnetic ring core adopts a vibration bed non hanging point coating process. The nylon coating is made of plastic material, which is impact resistant and has high resistivity. High grade magnetic ring cores use nylon as the insulation protection coating. The magnetic ring heated to a certain temperature enters the vibrating bed and uniformly adheres to the powder surface without the need for a second press leveling. The rough surface is used to wind copper wire, which does not slide and has high efficiency.