Method for thermomagnetic encoding of permanent magnet materials

A method of imparting a magnetic pattern to a body, comprising:

• a) providing at least one energy source, a body of permanent magnet material having an outer surface and a thickness, and at least one pattern guide having at least two areas which cooperate to direct energy in a pattern, said pattern guide being an integral part of the permanent magnet body at the outer surface of the permanent magnet body and comprising at least one of the areas defining a selected region and another one of the areas being a recess constructed and arranged to encompass the selected region having an extent sufficient to minimize heat transfer to any unselected portions of the permanent magnet body adjacent each one of the selected regions;
• b) directing energy from the source to each one of the selected regions of the outer surface in a direction generally transverse thereto at an intensity and for a time sufficient to heat the permanent magnet body to a selected depth of the thickness thereof, to a temperature sufficient to lower the coercivity thereof, thereby producing at least one heated selected region while minimizing heating of any unselected portions of the permanent magnet body adjacent the selected region;
• c) exposing each one of the heated selected regions to a magnetic field greater than the coercivity thereof and not strong enough to significantly affect the magnetic characteristic of any unselected portions of the permanent magnet body adjacent the selected region;
• and
• d) cooling each one of the heated selected regions while exposed to the magnetic field, whereby the selected region exhibits a magnetic characteristic different from the magnetic characteristic of unselected portions of the permanent magnet body adjacent the selected region.

A method of imparting a magnetic pattern to a body, comprising:

• a) providing at least one energy source, a body of permanent magnet material having an outer surface and a thickness, and at least one pattern guide comprising a solid body having at least two areas which cooperate to direct energy in a pattern onto the body of permanent magnet material, at least one of the areas constituted by a protrusion arranged generally transverse to the outer surface;
• b) directing energy from the source through the pattern guide and onto at least one selected region of the outer surface in a direction generally transverse thereto by directing energy from the source and through each one of the protrusions while maintaining each one of the protrusions in heat transfer relationship with a corresponding one of the selected regions, such energy being at an intensity and for a time sufficient to heat the permanent magnet body to a selected depth of the thickness thereof, to a temperature sufficient to lower the coercivity thereof, thereby producing at least one heated selected region while minimizing heating of any unselected portions of the permanent magnet body adjacent the selected region;
• c) exposing each one of the heated selected regions to a magnetic field greater than the coercivity thereof and not strong enough to significantly affect the magnetic characteristic of any unselected portions of the permanent magnet body adjacent the selected region;
• and
• d) cooling each one of the heated selected regions while exposed to the magnetic field, whereby the selected region exhibits a magnetic characteristic different from the magnetic characteristic of unselected portions of the permanent magnet body adjacent the selected region.

A method of imparting a magnetic pattern to a body, comprising:

• a) providing at least one energy source, a body of permanent magnet material having an outer surface and a thickness, and at least one pattern guide having at least two areas, said pattern guide comprising at least one selected region of the outer surface of the body defined by a respective one of the areas prepared with an energy-absorptive finish and any unselected portions thereof defined by one of the areas prepared with a relatively energy-reflective finish;
• b) directing energy from the source to at least one selected region of the outer surface in a direction generally transverse thereto at an intensity and for a time sufficient to heat the permanent magnet body to a selected depth of the thickness thereof, to a temperature sufficient to lower the coercivity thereof, thereby producing at least one heated selected region while minimizing heating of any unselected portions of the permanent magnet body adjacent the selected region;
• c) exposing each one of the heated selected regions to a magnetic field greater than the coercivity thereof and not strong enough to significantly affect the magnetic characteristic of any unselected portions of the permanent magnet body adjacent the selected region;
• and
• d) cooling each one of the heated selected regions while exposed to the magnetic field, whereby the selected region exhibits a magnetic characteristic different from the magnetic characteristic of unselected portions of the permanent magnet body adjacent the selected region.

A method of imparting a magnetic pattern to a body, comprising:

• a) providing at least one energy source, a body of permanent magnet material having an outer surface and a thickness, and at least one pattern guide, the permanent magnet body being suitable to embody first and second selected regions of, respectively, first and second magnetic characteristics, each one of the regions being defined by a portion of the outer surface and an underlying portion of the thickness of the permanent magnet body, and each one of the pattern guides being in the form of a solid body with openings;
• b) directing at least a portion of the energy from the source through the openings of the pattern guide and onto a corresponding one of the first selected regions in a direction generally transverse to the outer surface at an intensity and for a time sufficient to thereby simultaneously heat a selected depth of the first selected regions to a temperature sufficient to lower the coercivity thereof, while minimizing heating of any portions of the permanent magnet body adjacent the first selected regions;
• c) imposing a magnetic field on each one of the heated first selected regions greater than the coercivity thereof and not strong enough to significantly affect the magnetic characteristic of any portions of the permanent magnet body adjacent the first selected regions;
• d) cooling each one of the heated first selected regions while in the imposed field whereby each one of the first selected regions exhibits a first magnetic characteristic;
• e) directing at least a portion of energy from the source through the openings of the pattern guide and onto a corresponding one of the second selected regions in a direction generally transverse to the outer surface at an intensity and for a time sufficient to thereby simultaneously heat a selected depth of the second selected regions to a temperature sufficient to lower the coercivity thereof, while minimizing heating of any portions of the permanent magnet body adjacent the second selected regions;
• f) imposing a reverse magnetic field on each one of the heated second selected regions greater than the coercivity thereof and not strong enough to significantly affect the magnetic characteristic of any portions of the permanent magnet body adjacent the second selected regions, the reverse magnetic field having a polarity opposite to that of the magnetic field of step (c);
• and
• g) cooling each one of the heated second selected regions while in the imposed reverse magnetic field to thereby yield the second selected regions with a polarity reverse of the polarity of the first selected regions.

A method of imparting a magnetic pattern to a body, comprising:

• a) providing at least one energy source, a body of permanent magnet material having an outer surface and a thickness, and at least one pattern guide, the permanent magnet body being suitable to embody first and second selected regions of, respectively, first and second magnetic characteristics, each one of the regions being defined by a portion of the outer surface and an underlying portion of the thickness of the permanent magnet body, the pattern guide forming an integral part of the permanent magnet body at the outer surface thereof and comprising recesses, each one of the recesses constructed and arranged to encompass a corresponding one of the selected regions, each recess having an extent sufficient to minimize heat transfer from the selected regions to any portions of the permanent magnet body adjacent the selected regions;
• b) directing energy from the source through the pattern guide and to first selected regions in a direction generally transverse to the outer surface at an intensity and for a time sufficient to thereby heat a selected depth of the first selected regions to a temperature sufficient to lower the coercivity thereof, while minimizing heating of any portions of the permanent magnet body adjacent the first selected regions;
• c) imposing a magnetic field on each one of the heated first selected regions greater than the coercivity thereof and not strong enough to significantly affect the magnetic characteristic of any portions of the permanent magnet body adjacent the first selected regions;
• d) cooling each one of the heated first selected regions while in the imposed field whereby each one of the first selected regions exhibits a first magnetic characteristic;
• e) directing energy from the source through the pattern guide and to second selected regions in a direction generally transverse to the outer surface at an intensity and for a time sufficient to thereby heat a selected depth of the second selected regions to a temperature sufficient to lower the coercivity thereof, while minimizing heating of any portions of the permanent magnet body adjacent the second selected regions;
• f) imposing a reverse magnetic field on each one of the heated second selected regions greater than the coercivity thereof and not strong enough to significantly affect the magnetic characteristic of any portions of the permanent magnet body adjacent the second selected regions, the reverse magnetic field having a polarity opposite to that of the magnetic field of step (c);
• and
• g) cooling each one of the heated second selected regions while in the imposed reverse magnetic field to thereby yield the second selected regions with a polarity reverse of the polarity of the first selected regions.

A method of imparting a magnetic pattern to a body, comprising:

• a) providing at least one energy source, a body of permanent magnet material having an outer surface and a thickness, and at least one pattern guide, the permanent magnet body being suitable to embody first and second selected regions of, respectively, first and second magnetic characteristics, each one of the regions being defined by a portion of the outer surface and an underlying portion of the thickness of the permanent magnet body, the pattern guide comprising a solid body with at least one protrusion arranged generally transverse to the outer surface;
• b) directing energy from the source through the pattern guide and to first selected regions, in a direction generally transverse to the outer surface by directing energy from the source to and through each one of the protrusions of the pattern guide while maintaining each one of the protrusions in heat transfer contact with a corresponding one of the first selected regions, such energy being at an intensity and for a time sufficient to thereby heat a selected depth of the first selected regions to a temperature sufficient to lower the coercivity thereof, while minimizing heating of any portions of the permanent magnet body adjacent the first selected regions;
• c) imposing a magnetic field on each one of the heated first selected regions greater than the coercivity thereof and not strong enough to significantly affect the magnetic characteristic of any portions of the permanent magnet body adjacent the first selected regions;
• d) cooling each one of the heated first selected regions while in the imposed field whereby each one of the first selected regions exhibits a first magnetic characteristic;
• e) directing energy from the source through the pattern guide and to second selected regions in a direction generally transverse to the outer surface by directing energy from the source to and through each one of the protrusions of the pattern guide while maintaining each one of the protrusions in heat transfer contact with a corresponding one of the second selected regions, such energy being at an intensity and for a time sufficient to thereby heat a selected depth of the second selected regions to a temperature sufficient to lower the coercivity thereof, while minimizing heating of any portions of the permanent magnet body adjacent the second selected regions;
• f) imposing a reverse magnetic field on each one of the heated second selected regions greater than the coercivity thereof and not strong enough to significantly affect the magnetic characteristic of any portions of the permanent magnet body adjacent the second selected regions, the reverse magnetic field having a polarity opposite to that of the magnetic field of step (c);
• and
• g) cooling each one of the heated second selected regions while in the imposed reverse magnetic field to thereby yield the second selected regions with a polarity reverse of the polarity of the first selected regions.