Electrocoating for Furniture Finish

Electrocoating, or electroplating, is also known as electrophoresis, electrodeposition, or electropainting. It is the coating process for metal that uses the electricity attraction force to deliver the coating to the object. It is a major development in waterborne coating. Principally, it is used the electric attraction force between the different charges. The metal-painted object is charged as an anode or cathode while the paint solution is the ionic solution with the opposite electric charge. The ionic paint is attracted to attach to metal objects. Although it seems simple, the processing for applying the coating is rigorous, and very careful formulation is very important to make sure the process works well.

The system only works for metal objects. The metal needs to be pretreated well before going to the painting process. The metal objects to be painted are hung at the overhead conveyor, and substantial electrical connections are made. The objects are immersed in the paint solution with the opposite charge. The solution is a low solid (about 5% - 20% solution) and waterborne. The object can be anode or cathode, while the particle paint carries an opposite charge from the object being painted.

The anodic system is the system when the object being painted is the anode or positive electrode. The paint immersion is negatively charged. The paint thickness is controlled by adjusting the immersing time, the voltage, and the bath solution. Usually a thin film coating is resulted, about 1 or 2 mm in thickness. After the object has been coated, they emerge from the pollution and go to the cleaning, at which they are cleaned from the paint excess and then go for the baking. Baking schedules vary according to the type of paint and final properties needed.

The cathodic system is the opposite. The paint solution carries positive charge while the object is the negative electrode. Both the anodic and cathodic systems are very similar, but the properties of the paint result are not the same. Anodic systems apply paint to positively charged substrates. The negatively charged pigment and resin particles deposit onto the substrate (anode). One disadvantage of this process is that substrate metals dissolve and become incorporated into the coating, which affects surface properties. 

Cathodic electrocoating deposits paint onto negatively charged substrates and offers several advantages over anodic electrocoating. The metal dissolution of the substrate does not occur, cathodic electrocoating has the ability to deposit over contaminants, corrosion resistance is improved, and a better color consistency occurs over welded areas.

The paint bath has to be stirred or circulated continuously to keep at the workable concentration. The replacement of coating material must be added regularly to keep the paint concentration. The pH value of the solution also needs to be maintained at the proper value.

 The electroplating finish for metal furniture

The coating film that resulted is strong and very uniform in thickness with high adhesion properties. In the furniture finishing, it is mostly used to paint the small objects such as the component, the hardware, and the metal knockdown part. It is suitable to do the simple finish. Many colors of paint finish, including the gold, silver, or bronze finish, can be applied with this system with high efficiency. It is also a lot used to layer the basic paint as the corrosion protection.

It is not suitable to finish the complex and big product. The big object will need a big tank of paint solution that may be very expensive. It also cannot make a complex and artistic finish. It is more suitable to do the finishing process for the similar product in sizes and color with a big volume. The simple form products, such as the filing cabinet for office furniture, leg, or other component part, are the suitable products.