Controlling new die mechanisms for magnetic characteristics of super-large ferrite cores

If a super-large core with a groove is molded with an axial molding press replacing the conventional die set, uneven density distribution occurs in the core because the molding pressure considerably converges on the groove of the core. Since this induces the residual stress in the groove to be released during the sintering process, it is difficult with the conventional die set to obtain the necessary dimensional precision and satisfactory magnetic characteristics. We devised a die mechanism capable of solving these problems through the reduction of converging pressure on the groove. This new die mechanism improves the moldability and magnetic characteristics of super-large ferrite cores through the uniform distribution of density and magnetic characteristics