Electromagnetic pressing of powder iron for stator core applications

A method for fabricating a highly-dense stator core for use in alternating current generators and electric motors, said method comprising:

• providing an electrically conductive container having an exterior circumferential surface, an interior circumferential surface, and a longitudinal axis;
• positioning a mandrel having an exterior circumferential surface coaxially within an interior of the container, wherein the interior circumferential surface of the container and the exterior circumferential surface of the mandrel have surface features complementary to desired surface features of the stator core;
• filling the space defined between the interior circumferential surface of the container and the exterior circumferential surface of the mandrel with a iron-based powder coated with a dielectric material;
• disposing a helical coil of a conductor circumferentially about the exterior circumferential surface of the container;
• and
• producing a magnetic force on the container to isostatically compress the container radially inward thereby isostatically compressing the iron-based powder between the interior circumferential surface of the container and the exterior circumferential surface of the mandrel to achieve a compressed powder having a density of at least about 98% of the theoretical density, wherein the magnetic force is produced by energizing the helical coil with a high current pulse of electrical power.

A method for fabricating a highly-dense stator core for use in alternating current generators and electric motors, said method comprising:

• providing an electrically conductive ring having an exterior circumferential surface, an interior circumferential surface, and a longitudinal axis;
• positioning a die having an interior circumferential surface coaxially around an exterior of the ring, wherein the exterior circumferential surface of the ring and the interior circumferential surface of the die have surface features complementary to desired surface features of the stator core;
• filling the space defined between the exterior circumferential surface of the ring and the interior circumferential surface of the die with a iron-based powder coated with a dielectric material;
• disposing a helical coil of a conductor coaxially adjacent the interior circumferential surface of the ring;
• and
• producing a magnetic force on the container to isostatically compress the ring radially outward thereby isostatically compressing the iron-based powder between the exterior circumferential surface of the ring and the interior circumferential surface of the die to achieve a compressed powder having a density of at least about 98% of the theoretical density, wherein the magnetic force is produced by energizing the helical coil with a high current pulse of electrical power.