Demagnetizer is a kind of equipment used to eliminate residual magnetism produced by mechanical processing. It produces magnetic lines of force through electromagnetic coils, which directly or indirectly interferes with the magnetism of the original workpiece and demagnetizes the workpiece. The main demagnetizers in China are platform demagnetizer and frame demagnetizer. The platform degausser mainly degausses the workpiece by introducing the coil magnetic flux into a plane through the iron core. The frame demagnetizer mainly passes through the workpiece through the coil, so that the residual magnetism of the workpiece can be demagnetized by magnetic wire cutting. The degausser needs alternating current to magnetize the coil. The demagnetizer can be used as iron remover and other equipment after modification.