Rack or Barrel Electroplating?

Electroplating may be defined as a deposition process where a thin coating of metal is deposited on a surface by passing an electric current through a solution in which the plated part acts as the cathode. The anode is often composed of the metal being deposited. The solution, or plating bath, contains dissolved salts of the metals being deposited.

There are two basic types of deposition methods commonly used for electroplating, rack or barrel, and each has its own advantages and disadvantages. Both are dependent on the parts (being plated) seeing a DC current while in contact with the plating solution. Both methods work with a wide variety of plating technologies including gold, silver, zinc, nickel, tin and copper. When considering the most appropriate application technique, one will consider the differences in these plating application methods.

Barrel Plating

Barrel plating is preferred as an efficient and relatively low cost method of electroplating small parts. It is highly productive and much less labor intensive. However, as the current is low the time required to have the components exposed to the plating bath may be longer.

As suggested by the name, barrel plating incorporates a vessel that carries numerous parts to be plated within it. The two most common barrel shapes are the horizontal, hexagonally shaped cylinder and the oblique barrel which may resemble a cement mixer. They may be made of many materials but are most commonly constructed of rigid polypropylene due to its cost and chemical resistivity. Both use center bars or danglers to conduct the current to the parts inside the barrel as the barrel slowly rotates while immersed in the plating bath.

Rack Plating

Many parts are too delicate to survive the barrel application method or are simply too large. In these cases, we look to rack plating. Rack plating though more labor intensive allows for the near elimination of part damage, processing of larger parts and the ability to maintain strict tolerances in plating thickness. Additionally, a custom rack may insure uniform electrodeposits in deep cavities.

Contact Asterion for assistance with application equipment as well as chemical for your finishing applications.