Barrel plating is one of the most common types of electroplating processes. During electroplating, manufacturers use an electric current to transfer metal ions from a source material to another object. The metal ions form a protective coating on the new object, giving it new or enhanced properties, such as water resistance or corrosion resistance. One example is using zinc to coat steel, resulting in galvanized steel, which offers a much higher level of moisture resistance than uncoated steel.
The barrel plating process gets its name from the barrels used to hold the metal when this process was first introduced in the 19th century. During this time, manufacturers loaded steel nails or similar items into large wooden barrels filled with water. By adding an electrode and some other form of metal, manufacturers were able to transfer the metal coating onto the steel nails. Today, the barrels used in this process have been replaced by plastic or composite containers.
In modern barrel electroplating, the barrel is set on a spindle to allow users to tumble the objects. This tumbling helps the metal ions reach the entire surface of the metal, allowing them to spread out more evenly and provide a more thorough coating. This enhances the properties of the object even further than what is possible with a stationary barrel or container.
One of the primary advantages to barrel plating is its speed and low cost. Multiple items can be coated at once, which keeps labor and materials costs relatively low. This method also saves time on batch orders, and helps manufacturers maintain speed with high-volume products.
Like other electroplating processes, barrel plating helps to increase corrosion resistance or add strength to many types of objects. It can also be used to alter the appearance or texture of some metals, particularly for jewelry and finished objects. Barrel plating may also be used to create a more uniform, even surface on items that require refinishing.
Compared to other forms of electroplating, barrel plating works best for large loads of relatively small items. This includes things like bolts, screws, and other types of fasteners. This process is also used to plate jewelry and even electronic or mechanical components.
Barrel plating is generally not recommended for large objects, which don't fit well into standard electroplating barrels. Irregularly shaped objects also achieve better results with other forms of electroplating. Rack wire electroplating offers a more complete method of plating for these types of objects.