Barrel Plating

Barrel Plating

Barrel plating is used to electroplate small items which would be difficult to jig due to their size and/or shape (small fasteners, jewellery, etc). The barrel holds the items and is submerged in a plating bath. An electrode is positioned in the barrel which makes contact with the items as they tumble over it. The items to be coated therefore form the cathode. An anode, typically constructed from the metal to be plated is positioned in the tank, preferably close to the barrel.

Barrel Plating Rig

Concentrations of metals to be plated in the bath are vital to achieving a good quality coating. Mass transfer can be limited within the barrel and hence it is difficult to get good plating. With the application of the Susonence ultrasound process, plating rates are improved. Plating of washers with tin is shown below, the Susonence equipment produced the coating 15% quicker than the standard barrel.

Washers


There are also quality and operational benefits. In particular where alloys are used, the percentage of each metal can be more closely controlled. For example lead-tin alloys are among the small number of electrodeposited alloys which has found extensive commercial applications. One of its advantages is the good solderability of the eutectic 60%-40% Tin-Lead alloy at low temperature (183C), very interesting in electronic applications. Commercial baths use fluoborate salts to obtain the plating. The concentration of the components of the alloys must be as constant as possible to guaranty the optimal physical properties; if the concentration of the solution in the barrel decreases, the composition of the components of the alloys is not constant and the physical properties change. The use of the Susonence ultrasound process increases the quality of the tin-lead deposit, without the need to add more chemicals to the bath.


Additional information