While a lot of different metal finishing companies tend to favor barrel plating, there are many very good reasons to consider the alternative. Using a rack for the plating process provides several advantages, although it is certainly not the right process for everything that needs to be plated.
The basic process of rack plating is more time and labor intensive than barrel plating, which means it is slightly more costly. However, with a well-organized and experienced metal finishing company this process is still efficient and it can be used to provide an extremely uniform finish to the tolerances required.
The Process
To complete the process, parts are placed on a specially designed rack. This rack is non-reactive and is used over and over again in the plating solution. Each component or piece is manually attached to the rack, which may also be called a plating jig. They may be hooked on attachments on the rack or individually fixed to the rack.
This will depend on the shape and size of the component. Often this process is used for large parts or very irregularly shaped parts. The rack is then dipped into the bath for the time required. The parts are then removed from the rack, again by hand and further processed or packaged for shipping.
Control of Part Movement
One of the very big factors in using rack plating over barrel plating is the ability to carefully control any movement of the parts against each other. With barrel plating, the parts are simply placed in the barrels and then very slowly tumbled in the cage until they are plated to the desired finish.
The problem with this method for very delicate parts, or for parts with multiple shapes and edges, is that the tumbling can cause damage. This can include areas that become bent or misshapen through the contact of the part with the parts and with the sides of the cage.
Inspection
An additional benefit to the rack plating process is the employee “hands-on” aspect of the processing. When placing the items on the rack or removing them after plating, any possible quality control issues will be noted. This is often not the case for parts that go through the barrel plating method.
While plating metal components using the rack method is not the right process for all parts, it is important for specific types of parts. Always consider the risk to the parts of other plating methods before making a choice.
