Deposit Thickness & Uniformity
Electroplated articles produce a non-uniform surface as a natural phenomenon of the process. To understand this you must first understand that plating is an electrochemical process. In this process, the metal from the process is supplied from the anode (source of the plated metal) across the bath to the cathode (the part being plated) through direct current. Direct current takes the path of least resistance. Part geometry can shorten the distance to the anode, and thus decrease the electrical resistance. The least resistant path will carry more current and thus deposit more metal. Naturally, the areas of the part that are closer to the anode will see higher deposits than otherwise. Likewise, recessed and shielded areas will deposit more slowly. In the simplest terms, the inside of parts may see very little plating at all.
From an engineering standpoint, it is good to consider firstly, the dynamics of a surface and how it will electrochemically deposit plating. If every area of a part has to receive the minimum, this can significantly affect the cost of the part and in some cases may not be achievable without seriously compromising the overall aesthetic.
A term often used in this discussion is the functional significant surface. This is the area that must have the required thickness to perform in the field. This area of critical to service life parts should be agreed upon and or indicated in drawings where appropriate.
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