Industrial painting: types and advantages

Industrial Painting Using Cataphoresis, with Powder, Liquid, and High-Temperature Liquid Enamels

Argos services for surface treatments expands with three types of industrial painting: cataphoresis, powder coating, and liquid/high-temperature liquid painting.

Argos has four plants dedicated to powder coating and one for the application of liquid enamels.

The production cycle varies depending on the daily programme and involves the use of suitable hooks on which the parts to be painted are hung. The hooks are attached to the overhead transport chain in the painting line.

The work cycle is divided into three steps:

• Filler sealing for water-acoustic sealing and for an aesthetic effect when necessary;
• Thread protection when necessary;
• Determination of the cycle and choice of products to be applied.

Following automatic application of the enamel, the transport chain moves the parts to the curing oven, where polymerization and crosslinking of the paint film occurs. The type of resin, temperature, and time define the various crosslinking mechanisms.

Depending on the needs and industrial sector, three different types of painting are proposed: cataphoresis (or electrophoresis), powder enamels, liquid enamels, and high-temperature liquid enamels.

Cataphoresis

Cataphoresis, or electrophoresis, is a surface treatment that prevents corrosion on parts made of iron, steel, and other alloys, making them very resistant. In the process, an epoxy resin is deposited electrochemically on a metal surface (iron, aluminium, steel, etc.).

The separation of ions in electrophoresis allows the paint to settle uniformly on the surface, protecting it from corrosive agents.

To carry out the cataphoresis treatment, the metal part is immersed in a water-soluble paint bath where it is polarized by a cathode by means of an electrical current.

This causes the paint particles suspended in the liquid to migrate to the metal surface, where they settle uniformly.

The Advantages of Cataphoresis

In addition to offering high corrosion protection, electrophoresis provides important benefits:

• all areas are protected, even cavities or pointed tips;
• the entire surface is coated with a thin uniform layer with a thickness of 10–40 micrometres;
• cataphoresis also gives the surface an attractive appearance;
• it is an eco-friendly treatment that requires a reduced use of chemicals.

Painting with Powder and Liquid Enamels

Powder enamels were developed in the 1950s and spread as an alternative to liquid enamels. Today, the use of both is widespread because they offer a series of advantage depending on the various needs. Here they are in detail.

Differences Between Powder and Liquid Enamels

The main difference between the two treatments lies in the application. Powder enamels do not require the use of a chemical solvent, which is necessary for liquid enamels.

Liquid paint may be applied to a variety of indoor and outdoor surfaces, while powders are used on metal objects in industrial situations.

Powder enamel is applied using an electrostatic spray gun that distributes the powder on the surface. Since the paint is positively charged, it remains attached to the object. The object is then placed in an oven to melt the powder, creating a uniform finish.

Painting with High-Temperature Liquids

The surface treatments proposed by Argos also include painting with high-temperature liquids.

This process serves to guarantee a seal on metal parts subject to extremely high temperatures, such as heater parts, mufflers, barbecues, heating systems, and engine parts.

The characteristics of high-temperature liquid paints also include the elevated adherence on the surfaces, capacity for quick drying, and the use of low-emission solvents which are less hazardous for people and the environment.

After painting, Argos offers various finishing techniques such as tumbling, deburring, and dehydrogenation, for an excellent aesthetic result and greater durability of the treated piece.

For industrial painting, either powder or liquid enamels can be applied electrostatically. This method, called electrostatic painting, relies on electrical conductivity of the metal surface, facilitating the adherence of the paint to the substrate and consequently reducing overspray and consumption.