Spray Painting

What is the difference between spray painting and powder coating?

Spraying painting and powder coating can not only improve the appearance level of products, but also extend their service life. They are two widely used spraying processes. What is the difference between the two?

1. Principle

Powder coating: It is a relatively complex surface treatment process that uses equipment to directly spray coating powder on products, thereby providing protection and decoration. It is usually called electrostatic powder spraying.

Spray painting: It is a relatively simple surface treatment process, which involves placing paint into a container, applying pressure with mechanical equipment, and spraying the paint onto the product in the form of mist to form a paint film.

2. Usage scenarios

Powder coating: widely used in metal surface treatment technology and widely used in light industry and home decoration fields such as hardware, home decoration, building materials, etc.

Spray painting: widely used in fields such as ships, locomotives, bridges, machinery, wood, leather, etc.

3. Process flow

(1) Powder coating:

Before spraying, the product needs to be treated (rust removal, oil removal, etc.);

Due to the fact that this process is directly sprayed onto the product, the adsorption force is not very strong, but it also requires a high-temperature curing step;

Place the sprayed product in an oven at a certain temperature, and the coating powder will melt smoothly under high temperature, ultimately solidifying to form a dense and sturdy sprayed layer.

(2) Painting:

Before painting, the product needs to be treated (rust removal, oil removal, etc.);

The surface of the processed product should also be cleaned and dried naturally before painting on the product;

Some spray a layer of paint directly, while others repeatedly spray 2-3 times to obtain a dense and firm paint layer, so the first spray is also called primer, and after polishing, the next spray is carried out.

4. Process characteristics

Powder coating:

Powder can be used directly without diluting the liquid;

Less harm to the environment and human body;

The coating quality is good and the adhesion is strong after electrostatic spraying;

Low technical requirements for workers;

There are many advantages such as short curing time and no liquid hanging;

Powder coating also has the disadvantages of difficult surface repair and high cost.

Painting:

1) Manual spray painting (handheld spray gun: spray products according to the shape of the workpiece)

A. Flexible and convenient operation;

B. Suitable for products of different environments, shapes, and sizes;

C. Simple equipment with low energy consumption;

D. The disadvantage is low production efficiency and unstable spraying quality;

E. Workers have high labor intensity, are susceptible to paint mist pollution, and have poor working conditions.

2) Air spray painting (using a spray gun as a tool, the paint is blown and atomized by compressed air flow, and sprayed onto the surface of the product to form a paint film)

A. High productivity and stable spraying quality;

B. A large amount of paint mist is generated during the painting process, polluting the air;

C. High paint loss;

D. Moisture and other impurities in compressed air are easily mixed with paint flow, and unclean treatment can affect the quality of the coating.

3)High pressure airless spray painting (using a high-pressure pump inside a sealed container, the paint is sprayed out from the spray gun, and due to a sudden drop in pressure, it immediately expands and atomizes violently, spraying onto the surface of the workpiece to form a paint film)

A. High productivity, strong adhesion of paint film;

B. Less paint mist, low degree of air pollution;

C. Good working conditions;

D. Due to the absence of impurities such as water and oil in the paint flow, the protective performance of the coating is good;

E. The disadvantage is that the equipment structure is complex, the coating is not as uniform as air spray painting, and the decoration is poor.

5. Other differences

(1) The smoothness of spray painting is better than powder coating because the molecular structure of the additives and solvents used in spray painting contributes to smoothness, which is not present in powder coating.

(2) In spray painting, small areas can be repaired easily, while powder coating cannot;

(3) The flexibility of spray painting is better than that of powder coating, so spray painting parts can be bent in small sizes;

(4) Compared with powder coating, spray painting has more diverse decorative features and faster delivery time. Spray painting is more easy to be customized or do small batch production;

(5) Powder coating requires high temperature baking, so the adhesion is better, but it will have requirements for product size. Spray painting does not need to have requirements for product size, and can be sprayed on a large area.