Laser treatment of electrical steel and optical scanning assembly therefor
AssigneeArmco Inc.
InventorGary L. Neiheisel
Life of this patent
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Abstract
Apparatus for scanning a continuous wave Nd:YAG laser beam across a moving strip of grain oriented silicon steel having an insulative coating to subdivide the magnetic domains of the strip to improve core loss without damage to the insulative coating. The laser beam is scanned by a multiple-faced rotating mirror and focused onto the strip surface by a flat field lens and cylindrical lens to produce a scan line of narrow width having the required irradiation energy, dwell time and line spacing at the surface of the moving strip.
Claims20
In apparatus for the continuous manufacturing of an indefinite length strip of magnetic material of the type having a plurality of magnetic domains and an insulative coating thereon, said strip moving at a substantially constant speed, the improvement in combination therewith comprising a laser producing a laser beam, and means for focusing said beam onto the surface of the moving strip so as to produce in the strip a narrow line of subdivided magnetic domains without damage to the insulative coating.
A method of laser treating as indefinite length strip of magnetic material of the type having a plurality of magnetic domains and an insulative coating thereon comprising moving the strip at a predetermined substantially constant speed in a predetermined direction and repetitively and continuously scanning a laser beam across the width of the moving strip transversely of said predetermined direction so as to produce on the surface of the strip a plurality of narrow lines of subdivided magnetic domains spaced in the direction of strip travel without damage to the insulative coating.
Dependencies are inferred from the claim text.