International Business Machines Corporation

Edward Allan Highum

Scott Marvin Thorvilson

Ewald E Stadler

Alfred Wilhelm Mueller

Thomas William Nash

An enclosure for an electronic device forms a barrier to electro-magnetic radiation. A typical cross-section of the enclosure comprises three parallel layers. The outer and inner surface layers are of a polymeric base material in which is suspended an electrically conductive fill material, giving the surface layers relatively high electrical conductivity. The middle layer is of a polymeric base material, in which is suspended fill material having high magnetic permeability, giving the middle layer relatively high magnetic permeability. In the preferred embodiment, the enclosure is constructed using a co-injection molding process. Nickel-coated graphite (high conductivity) in a polymeric base is injected into a mold from the outer co-injection nozzle, while carbonyl iron powder (high permeability) in a polymeric base is injected into the mold from the inner co-injection nozzle. The resultant molded structure contains the three layers described above, yet can be made inexpensively in a single co-injection molding operation. The enclosure may comprise multiple co-injection molded pieces, which are attached together by any of various conventional means.

Method for manufacturing electro-magnetic shield having multiple

An enclosure for an electronic device forms a barrier to electro-magnetic radiation. A typical cross-section of the enclosure comprises three parallel layers. The outer and inner surface layers are of a polymeric base material in which is suspended an electrically conductive fill material, giving the surface layers relatively high electrical conductivity. The middle layer is of a polymeric base material, in which is suspended fill material having high magnetic permeability, giving the middle layer relatively high magnetic permeability. In the preferred embodiment, the enclosure is constructed using a co-injection molding process. Nickel-coated graphite (high conductivity) in a polymeric base is injected into a mold from the outer co-injection nozzle, while carbonyl iron powder (high permeability) in a polymeric base is injected into the mold from the inner co-injection nozzle. The resultant molded structure contains the three layers described above, yet can be made inexpensively in a single co-injection molding operation. The enclosure may comprise multiple co-injection molded pieces, which are attached together by any of various conventional techniques.

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Kasson, MN, United States of America

Edward Allan Highum