The transformer core is generally processed in the following steps:

Raw material preparation

1. material selection: usually choose silicon steel sheet as the main material, according to the performance requirements of the transformer, select the appropriate grade and specification of silicon steel sheet, such as high permeability, low hysteresis loss and low eddy current loss of silicon steel sheet.
2. Quality inspection: carry out strict quality inspection on the purchased silicon steel sheet to check whether there are problems such as corrosion, surface defects, magnetic properties do not meet the requirements and so on.

Processing of silicon steel wafers

1. Shearing and discharging
CNC shear: use CNC shear to cut the silicon steel sheet accurately according to the design size and shape requirements. This method can realize fast and accurate shearing with high dimensional accuracy.
Laser cutting: For some iron cores with complex shapes and high precision requirements, laser cutting technology can be used. Utilizing the high energy density of laser, the silicon steel sheet is finely cut.
2. Stamping molding: According to the specific shape and structure of the core, various holes, slots and other structures are punched out on the silicon steel sheet through the stamping process, such as holes for winding windings, holes and slots for installation and fixation.
3. Surface treatment
Insulation coating treatment: In order to reduce eddy current loss, an insulating coating is applied on the surface of silicon steel wafers, such as impregnation of insulating varnish, spraying insulating varnish, etc., so as to insulate the silicon steel wafers from each other.
Deburring and Cleaning: Deburring the silicon steel sheet after shearing and stamping is carried out to remove the burrs and sharp corners of the edges, so as to prevent scratches to the insulation layer or injuries to the operators in the stacking process. At the same time, clean up oil, dust and other impurities on the surface of the silicon steel sheet.

Core stacking and fastening

1. Selection of stacking method
Stacking method: Staggered stacking of silicon steel sheets, this way can make the magnetic circuit of the core smoother, reduce the magnetic resistance and improve the magnetic properties.
Winding method: the silicon steel strip coiled into cylindrical or other shapes of the core, suitable for some special structure of the transformer, such as toroidal transformer core.
2. stacking operation: according to the designed stacking order and method, the treated silicon steel sheet is stacked one by one, in the process of stacking, the stacking precision of silicon steel sheet should be strictly controlled to ensure that the gap between the sheets is even, the silicon steel sheet is aligned, to avoid the occurrence of wrong sheet, slanting sheet and so on.
3. Fastening
Bolt fastening: For large transformer core or iron core that requires high mechanical strength, bolts can be used to fasten the core parts together.
Welding fastening: through the welding process will be iron core silicon steel sheet connected together to form a whole. The welding temperature and welding time should be well controlled to avoid overheating, resulting in a decline in the magnetic properties of the silicon steel sheet.

Iron core processing after treatment

1. Trimming: trim the whole core after stacking and fastening, remove the welding slag and burr on the surface to make the surface of the core flat and smooth.
2. Insulation treatment: check and repair the insulation coating which may be damaged in the stacking process again, to ensure that the insulation performance of the iron core is good. For some higher requirements of the transformer core, may also be vacuum dipping paint treatment, further improve the insulation and moisture resistance.
3. Inspection
Size detection: the use of gauges to measure the dimensions of the core, such as the core thickness, width, length, window size, etc., to ensure that the dimensions meet the design requirements.
Magnetic performance testing: through the professional magnetic performance testing equipment, the magnetic induction strength of the core, magnetic permeability, hysteresis loss and other magnetic performance parameters to assess whether the performance of the core meets the use of the transformer requirements.
Appearance inspection: check whether the appearance of the iron core is flat, no corrosion, no deformation, etc., whether the surface insulation coating is uniform, no flaking and other phenomena.