Most of the times, engineers select a type of surface treatment with very little idea about how that coating is obtained. Some knowledge of electroplating process can help to achieve better results. There are some key factors mentioned below to be considered by engineers for designing for electroplating :
Jigging: Parts which are to be electroplated needs to be held during processing. This provides dual function of holding the component and providing electrical contact. Many a times it is required to add additional tooling holes to design of a part specially for jig contacts so the electroplating can be continuous over all other surfaces and part can still be held securely. Number of different designs of jig are available, including variety of standard metric thread sizes. Parts can also be held using wires.
Airlocks and cavities: The geometry of parts for electroplating can cause airlocks, where air cannot escape. This can prevent formation of anodized coating, limit coating thickness and inhibit dyeing. Trapping of chemical in cavities during processing is another issue caused by geometry of parts. These cavities can cause serious quality issues like corrosion or staining when the chemical seeps out of cavities after processing. To avoid airlocks and cavities, electroplating chemical manufacturers recommend adding drainage holes to the design of component.
Welds: Incomplete welds creates small cavity which also pose risk of chemical entrapment. When welds completely cover a large void, the entrapped air can cause the part to float in processing tanks. Any weld flux should be removed mechanically before sending items for electroplating as per plating chemical manufacturers.
Choice of base material: Original condition of part will have strong influence on appearance of coated part. Electroplating cannot hide scratches, pits or marks on present already on base material. Electroplating chemical manufacturers advice to complete mechanical finishing before sending parts for electroplating. Inserting foreign materials to base material can cause problems. Mixing different alloys in an assembly which is to be anodized should be avoided according to plating chemical manufacturers.
Tolerances: Electroplating is process of deposition on surface base material, hence changes in dimensions of plated parts are easily calculated. An anodized coating extends into the base material as well as growing from original surface. The anodized coating is approx 50% ingress and 50% growth. Electroplating chemical manufacturers provide facility to estimate the of feature after anodizing.
Having some prior knowledge electroplating to improve production, affordability, final plating results and achieving design intents.
