The physical properties of the moulded plastic strongly influence the strength of the electroplated structure because fracture often occurs in the plastic. The chemical nature and structure of the plastic determine whether surface treatments can lead to a durable bond to the subsequently deposited metal. The differences in the physical properties of the metal and plastic determine the stress that the metal-plastic structure will experience in service. The temperatures and conditions under which the part is fabricated will determine the ultimate load that the structure must bear without failure. The chemical natures of the metal deposits control part durability in wet and corrosive environments. Failure modes and methods for controlling the durability of the electroplated plastic part during fabrication are emphasized.Electrodeposited metallic coatings are applied to plastics primarily to produce complex, lightweight, durable parts that have a metallic appearance. Nearly any electrodeposited metal can be used 1 including copper-nickel-chromium, brass, silv'er, gold, and copper. Plastic parts coated with decorative electrodeposits are used extensively in the automotive, appliance, plumbing, and novelties industries.Similar processes are being used in the electronics industry to fabricate additive printed circuit boards. 2 ,3 Several techniques are available to deposit selectively the desired conductive circuit pattern on to the epoxy substrate. The copper current paths can then be built to the desired thickness with either electrodeposited or chemical copper. Causes of and corrective actions required to solve the various adhesion problems that can occur in the manufacture of printed circuit boards have been reviewed. 4Electrodeposited metal coatings are used in a few engineering applications to make plastic parts, thermal or electrical conductors, or electromagnetic shields. Electroplated plastics have higher heat distortion temperatures than the unplated plastics, and metal deposits have been used to a limited extent to protect the polymer substrate from light or chemical decomposition.Several methods are available for metallic coating of non-conductors that normally do not R. G. Wedel, BS, PhD, is with the Shipley Company, Newton, Mass., USA. develop significant adhesion between the metal coating and the substrate. These processes are useful for electroforming applications, including metalworking dies, engraving plates, and phonograph masters; for fabricating a small number of large or complex metal parts; and for producing decorative metallic coatings on glass, wood, plants, and insects. These techniques 5 -7 for encapsulating non-conductors with metals include silver spray methods, bronz ing, graphitizing, metallic paints, 'conductive' plastics, vacuum metallizing, cathode sputtering, gas plating, hot stamping, and flame spraying. The first five treatment's are usually followed by electrodeposition of a thick metal coating. These processes normally require a large amount of hand labour and thick electrodeposits...
