Plating on Plastic: Causes of Common Imperfections

There are a variety of conditions during the molding, handling, and plating of plastic components which could potentially lead to imperfections in the finished product. Understanding the causes of some of the common imperfections can aid in identifying root causes of these imperfections and effective implementing corrective actions throughout the supply chain.

Splay

Splay is a cluster of breaks, mars, or marks, visible on a plated part. Though it is only visible once plated, it is caused my molding issues; trapped moisture in the plastic can come to the surface during the plating process, causing splay.

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Component exhibiting splay

Flash

Flash is a protrusion of plastic on a part edge. Flash on a molded component often goes unnoticed until after the component has been plated, because plating builds up on the protrusion. This plate buildup can make the edge of the part sharp, and can also interfere with fit and appearance. This imperfection is caused during molding by excess plastic or the component not breaking from the mold cleanly.

Blisters

Blisters, like the skin condition, are air pockets beneath the skin—in this context, between the plastic and the metal deposit. Like splay, blisters can be caused by moisture trapped within the molded component; however, blisters can also be caused during the plating process, between layers of metal deposit. To determine the cause of a blister, cut and peel the blister back. If it originates at the plastic, and the underside of the blister has plastic that has separated from the component, the blister resulted from trapped moisture in molding.

Scratches and Dents

Scratches and dents can be caused during molding or handling (of the raw or plated part). While the plater will generally perform an incoming audit on molded components for plating, some scratches or dents in the plastic may not be immediately obvious, or raw parts may be scratched during handling. Scratches and dents can also occur during handling post-plate; it may be possible tell by the depth of the scratch or dent and plating deposit on the area whether the imperfection is superficial or in the base material.

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Scratch on a chrome plated component

Dry Down

Dry down is marred plating and it occurs during the plating process when the part becomes too dry between metal deposits. This can be avoided by careful process control of the plating operation.

Warp

Warp is the dimensional distortion of a component and can occur at a few stages of the production process. Molding errors could cause warp, and warp could also be caused by exposure to extreme temperatures, racking the part incorrectly, or mishandling the part.

Skip plate

Skip plate is the absence of plating on a surface—the base material is exposed. It can be caused by contaminants on the surface of the part, which prevent the plating from being deposited on the surface of the part. Ensuring that raw parts are handled properly and kept free of surface contaminants can reduce the occurrence of skip plate.

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