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Insulation of Laminated Structures

IP.com Disclosure Number: IPCOM000081092D
Original Publication Date: 1974-Apr-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Daughenbaugh, GA: AUTHOR [+4]

Abstract

Laminae of metal foil are stacked and bonded to provide laminated induction cores. Such structures are useful in transformers, motors, generators, transducers and similar electromagnetic embodiments. Where the laminae are thin and formed by etching or other techniques which leave them with a sharp edge, the resultant laminated structure exhibits a destructive cutting profile. For example, insulated wire subsequently placed in contact with the stack, is subject to having its insulation either broken down or cut by the sharp edges in the stack.

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Insulation of Laminated Structures

Laminae of metal foil are stacked and bonded to provide laminated induction cores. Such structures are useful in transformers, motors, generators, transducers and similar electromagnetic embodiments. Where the laminae are thin and formed by etching or other techniques which leave them with a sharp edge, the resultant laminated structure exhibits a destructive cutting profile. For example, insulated wire subsequently placed in contact with the stack, is subject to having its insulation either broken down or cut by the sharp edges in the stack.

The production of laminae by etching from foil is attractive, especially where the laminae are to be small, as it allows the production of many precise and unstressed members utilizing batch fabrication techniques. The sharp edges of laminated structures formed from a plurality of etched laminae can be treated to remove and cover their sharp edges.

After the laminated structure is formed, the stack is placed at the cathode of a vacuum sputtering apparatus. Activation of the apparatus then results in smoothing and rounding of the sharp edges by sputter-etching. If desired, subsequent deposition of a dielectric material on the smooth stacks provides insulation and additional smoothing. Where the deposited dielectric material is sputtered, it can be very thin and thus allow close inductive contact between the wire and the stack. Dielectric material suitable for deposition includes aluminum oxi...