The electrostatic powder coating technology has been present worldwide since the 1950s and has seen significant advancements. In Vietnam, in recent years, electrostatic powder coating technology has developed across various manufacturing sectors. This article will elucidate the fundamental knowledge about this technology and the development directions of Vietnamese enterprises.

Overview of Electrostatic Powder Coating Technology

The Principle of Electrostatic Powder Coating

Electrostatic powder coating is a method of applying a paint layer (containing resin, pigments, and additives) to the surface of materials (metal or non-metal) using electrostatic principles. Paint particles carrying a negative charge (-) adhere to the material to be coated, which carries a positive charge (+).

Electrostatic Powder Coating Process

Cleaning -> Drying -> Inspection -> Powder Coating

Applications of Electrostatic Powder Coating

Electrostatic paint can be applied to non-metallic materials such as plastic, wood, ceramics, but it is most commonly used on metals such as aluminum, zinc, and copper. Electrostatic painting has many advantages over traditional water-based paint for a long time, so it is now widely used in various fields:

  • Furniture and Decorative Items
  • Outdoor Construction Materials: Fence, Gate, Railing
  • Industrial Products: Electrical Cabinets, Shelves, Power Outlets
  • Products for Automobiles, Motorcycles, and Bicycles.

The electrostatic painting situation of businesses in the Northern region

Currently, there are two methods of surface painting products to protect them before reaching the hands of consumers, namely traditional water-based paint and electrostatic paint. Depending on the product characteristics and customer requirements, some small businesses still use traditional water-based paint, but the majority of manufacturing companies use electrostatic paint. In particular, electrostatic paint is used in fields that require high quality such as electrical cabinets, shelves, drainage pipes, steel structures, electronic products, automobiles, motorcycles, etc.

However, some enterprises still omit the electrostatic painting step in the production process for various reasons such as initial investment costs, insufficient space to carry out the electrostatic painting process, etc.

Enterprises investing in electrostatic painting can be divided into two types. The first type includes companies specialized in electrostatic painting, primarily catering to the needs of customers, factories, and small businesses requiring electrostatic painting. The main products include railings, gates, shelves, fences, etc. Companies specializing in electrostatic painting are currently limited in number, with small-scale operations, and lower technological levels. The second type consists of machinery manufacturing companies, especially those with large annual production quantities

Based on the author’s investigation, the majority of companies in the Northern region use electrostatic painting systems through either automatic or manual methods. This implies that some steps in the painting process may be omitted or streamlined, and the quality of the paint and productivity still depend on the skill and expertise of the workers. Only a few large companies are capable of investing in a complete automated electrostatic painting system.

Surface Cleaning Stage

The surface cleaning stage is a crucial step in the electrostatic painting process. However, many companies approach this stage laxly, skipping or using outdated technologies. Numerous companies rely solely on manual sanding machines and wire brushes for this task.

In contrast, larger companies have implemented thermal sanding or sandblasting systems to clean metal surfaces. This is an optimal method as it improves production efficiency and surface quality, extends product lifespan, and contributes to environmental protection and workforce health. However, for small companies without unique products, those rooted in tradition, or lacking sufficient financial resources, investing in a sanding system can pose a significant challenge.

Drying Stage

After the cleaning process, the metal surface is dried. There are various drying methods such as infrared drying, gas-fired drying, natural drying, etc. Gas-fired drying is a method that uses metal heat guns for drying, which is simple and effective. The products are suspended on a conveyor system and pass through a controlled temperature and automatic speed drying oven. Natural drying is only suitable for small metal sheets. Each drying method has its own advantages and disadvantages, but some companies still carry out the drying process manually without careful attention, affecting the adhesion of the paint to the surface.

Primer Coating Stage

In principle, a product needs to undergo the primer coating stage to enhance the adhesion of the material’s surface. However, many companies still skip this step to save raw materials and production costs. Additionally, there are cases where companies adhere to customer requirements and skip the primer coating.

The Final Coating Stage

The product will be completed using an automated spray painting system to ensure an even and high-quality paint layer. Companies may use single or dual spray guns depending on the production line. The quality and color of the paint layer are determined by precise mixing ratios. Before painting, it is essential to ensure that the metal surface is clean and free of dust, as well as thoroughly checking the hanging hook and conveyor system. Each product will be spaced about 100-200mm apart when hung. During manual painting, it is crucial to adhere to the correct painting sequence, starting from the corners and edges, flat surfaces, underneath, and on top. Special attention should be paid to the direction of painting to avoid affecting the person standing on the opposite side.

Drying and Finishing Stage

After completing the painting process, the product is moved into the drying oven. At this stage, the paint will adhere firmly and evenly to the surface of the product.

Product Inspection

The product undergoes visual inspection to assess color, adhesion, and paint coverage. In cases of higher requirements, specialized measuring equipment is used to check paint thickness and adhesion.

The potential of the electrostatic painting industry

Based on the information provided, the potential of the electrostatic painting industry in Vietnam is significant. Faced with increasingly intense competition, businesses are likely to invest in electrostatic painting systems and supporting equipment to meet the stringent standards of markets such as Japan, the United States, and Europe. Currently, in the Northern provinces, an increasing number of companies have invested in complete and automated electrostatic painting systems to serve the painting of electrical cabinets, shelves, fences, steel structures, electronic products, automobiles, motorcycles, etc. These companies have received high praise from both domestic and international customers and partners.

In this article, we focus on the activities of Vietnamese businesses. In the next article, we will introduce the activities of foreign companies, such as those from Japan and other multinational corporations.

However, before providing analyses of the activities of foreign companies, it is important to note that the electrostatic painting industry is rapidly developing in Vietnam. For businesses operating in this sector, enhancing product quality and investing in electrostatic painting technology are crucial for staying competitive in the market.

Some large-scale enterprises have implemented complete automated painting systems, enhancing production efficiency and product quality. However, there are still many small and medium-sized enterprises with non-unique products or insufficient financial resources to invest in modern electrostatic painting technology.

In the context of an increasingly open economy, Vietnam’s electrostatic painting industry will also have to face numerous opportunities and challenges from the international market. Therefore, investing in improving product quality, upgrading technology, and training a high-quality workforce will be decisive factors for the success and sustainable development of the electrostatic painting industry in Vietnam in the future.

This is an introductory article providing an overview of the electrostatic painting industry in Vietnam and the activities of businesses in this sector. I hope that this information has helped you gain a better understanding of this industry and its potential for the future.

(Source: NC Network Vietnam, Nguyen Hoang Hang, Hawee P&T
HTCO Viet Nam, Seiki Innovations Viet Nam)