Browse Prior Art Database

Production of Metal Surfaces on Plastic Parts

IP.com Disclosure Number: IPCOM000086922D
Original Publication Date: 1976-Nov-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 13K

Publishing Venue

IBM

Related People

Damm, EP: AUTHOR [+3]

Abstract

Much of the low-cost advantage of using polymeric materials as external covers, housings, etc., in electronic equipment is lost as a result of having to provide electromagnetic (EMC) shielding capability. This EMC shielding has been provided in a number of ways, e.g., embedding metal mesh screens, vacuum depositing, flame spraying, electroless plating metals and using large volumes of metal fillers. Each method is expensive or has been found to have certain inherent problems (adhesion, part distortion, structural integrity, etc.)

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Production of Metal Surfaces on Plastic Parts

Much of the low-cost advantage of using polymeric materials as external covers, housings, etc., in electronic equipment is lost as a result of having to provide electromagnetic (EMC) shielding capability. This EMC shielding has been provided in a number of ways, e.g., embedding metal mesh screens, vacuum depositing, flame spraying, electroless plating metals and using large volumes of metal fillers. Each method is expensive or has been found to have certain inherent problems (adhesion, part distortion, structural integrity, etc.)

The present techniques are electrically efficient, have excellent metal-to- polymer adhesion, and are inexpensive compared to the other techniques. Specifically, the techniques involve the use of fine metal particles spread as a monolayer, or slightly larger, over the surface of the molded part.

Technique 1: A magnetizable mold is dusted while magnetically energized with a magnetic metal or alloy (iron, nickel, alnico, etc.). The mold is kept magnetized to ensure the material stays in place during the molding operation. The polymeric material, e.g., sheet molding compound or liquid resinous material, is placed within the mold cavity. During the molding operation the magnetic field holds the metal in place such that the polymeric material surface captures but does not totally encapsulate the metal. Upon release of the mold, the metal powder is now available on the surface for EMC shielding. This also avoids losing structural integrity which happens when an attempt is made to use high loading in the resin of conductive material. An additional feature of the "metal surface layer" is that electroplatin...