Construction Methods, Advantages and Disadvantages of Conformal Coating Materials and Application Analysis

 

Conformal coating, as a special coating material, is widely used in many fields such as electronics, aerospace, and automobiles. It can form a uniform and continuous protective film on the surface of the coated object, playing multiple protective roles such as moisture prevention, salt spray prevention, mold prevention, and corrosion prevention, thereby improving the reliability and service life of the product. Different construction methods have an important impact on the performance of the conformal coating, as well as construction efficiency, cost, and other aspects. This article will introduce the common construction methods of conformal coating materials in detail and analyze their respective advantages and disadvantages.

Common Construction Methods of Conformal Coating Materials

Brushing

Brushing is a relatively traditional and simple construction method for conformal coatings. During construction, a brush is used to dip an appropriate amount of conformal coating materials and then evenly apply it to the surface of the coated object. This method is relatively easy to operate and does not require complex equipment. It has good applicability for some irregularly shaped, small-area, or parts that are difficult to be constructed by other methods.

Advantages

1. Simple equipment: Only basic tools such as brushes are required, and there is no need to purchase expensive spraying equipment or other special devices, with a low initial investment cost.
2. Flexible operation: Local areas can be easily repaired and coated. For some complex-shaped parts with corners, gaps, and other areas that are difficult to spray, the coating can be accurately applied.
3. Save coating: Compared with methods such as spraying, there is less waste of coating during brushing. The amount of coating can be better controlled, especially suitable for conformal coatings with higher prices.

Disadvantages

1. Low construction efficiency: Manual brushing is relatively slow, and large-area coating work requires a lot of time and manpower, which is not suitable for large-scale production.
2. Uneven coating thickness: Since it is difficult to completely maintain the same force and speed during the manual brushing process, it is easy to cause uneven coating thickness, affecting the protective effect and appearance quality of the coating.
3. May introduce impurities: Brushes may drop bristles and other impurities during use, which may mix into the coating and affect the quality of the coating.

Spraying

Spraying is a widely used construction method for conformal coatings at present. According to different spraying equipment and principles, it can be divided into air spraying, airless spraying, and electrostatic spraying.

Air Spraying

Air spraying atomizes the coating by using compressed air and sprays it onto the surface of the coated object. It mixes air and coating through a spray gun, making the coating form fine mist droplets that evenly cover the surface of the object.

1. Advantages

• High construction efficiency: It can quickly cover large areas, is suitable for large-scale production, and greatly shortens the construction time.
• Uniform coating: By adjusting the parameters of the spray gun, such as air pressure and coating flow rate, a relatively uniform coating thickness can be obtained, improving the quality and appearance effect of the coating.
• Strong adaptability: It can spray various types of conformal coatings, including solvent-based and water-based ones, and has good adaptability to objects of different shapes and sizes.

2. Disadvantages

• Large coating waste: During the spraying process, part of the coating will disperse into the air in the form of mist droplets, resulting in coating waste and increasing the construction cost.
• Require professional equipment and site: Air spraying requires the installation of professional equipment such as an air compressor and a spray gun, and a special spraying site is needed to ensure the cleanliness and safety of the construction environment.
• High requirements for operators: Operators need to master certain spraying skills, such as the distance, angle, and moving speed of the spray gun. Otherwise, coating defects such as sagging and orange peel are likely to occur.

Airless Spraying

Airless spraying directly pressurizes the coating through a high-pressure pump, and the coating is atomized after being ejected from the nozzle. Compared with air spraying, airless spraying does not require compressed air, reducing the influence of moisture and impurities in the air on the coating.

3. Advantages

• High coating utilization rate: Due to the absence of air participation, the atomization effect of the coating is better, and it can adhere to the surface of the object more effectively, reducing coating waste and improving the coating utilization rate.
• Good coating quality: Airless spraying can obtain a thicker coating. The thickness of a single spray is larger than that of air spraying, reducing the number of spraying times and improving the construction efficiency. At the same time, the compactness and adhesion of the coating are also better.
• Suitable for high-viscosity coatings: It can spray high-viscosity conformal coatings and has better adaptability to some coatings with special performance requirements, such as thick-film conformal coatings.

4. Disadvantages

• High equipment cost: Airless spraying requires the installation of expensive equipment such as a high-pressure pump, and the purchase and maintenance costs of the equipment are relatively high.
• Difficult operation: Due to the high pressure of the coating, improper operation may cause the coating to splash, posing a threat to the safety of the operator. At the same time, higher operating skills are required to ensure the quality of the coating.
• High requirements for the environment: A large amount of noise will be generated during the airless spraying process, and construction needs to be carried out in a special soundproof site. Moreover, the atomization effect of the coating is good and it is easy to diffuse in the air, requiring good ventilation conditions.

Electrostatic Spraying

Electrostatic spraying makes the coating particles charged by using a high-voltage electric field, and then, under the action of the electric field force, the coating particles are adsorbed onto the surface of the coated object.

1. Advantages

• Extremely high coating utilization rate: Due to the electrostatic adsorption effect, the coating particles can be more accurately attached to the surface of the object, reducing the dispersion of the coating. The coating utilization rate can reach more than 90%, greatly reducing the construction cost.
• Excellent coating quality: Electrostatic spraying can make the coating particles evenly distributed on the surface of the object, forming a very uniform and compact coating, improving the performance of the coating such as corrosion resistance and wear resistance.
• High degree of automation: It can realize automated production, reducing the errors and labor intensity of manual operation, and improving the production efficiency and the stability of product quality.

2. Disadvantages

• Complex and expensive equipment: Electrostatic spraying requires the installation of complex equipment such as an electrostatic generator and a spray gun. The investment cost of the equipment is relatively high, and regular maintenance and calibration are required.
• Strict requirements for the environment and objects: Electrostatic spraying needs to be carried out in a dry and clean environment, otherwise it will affect the charging effect of the coating and the quality of the coating. At the same time, the coated object needs to have good electrical conductivity, and special treatment is required for some non-conductive objects.
• Safety hazards: There is a certain electrostatic risk during the electrostatic spraying process, and effective anti-static measures need to be taken to prevent safety accidents such as fires and explosions caused by static electricity.

Dipping

Dipping is to completely immerse the coated object in a container filled with conformal coating, and then take it out to make the coating form a uniform coating on the surface of the object. This method is suitable for the coating of small-sized and batch parts.

Advantages

1. Higher construction efficiency: For batch small-sized parts, dipping can process multiple parts at one time. Compared with methods such as brushing, it improves the construction efficiency.
2. Uniform coating: Since the parts are completely immersed in the coating, it can ensure that all parts are evenly coated with the coating, reducing the problem of uneven coating thickness.
3. Simple equipment: Only a container filled with the coating and some simple hanging devices are needed. The equipment cost is low and the operation is convenient.

Disadvantages

1. More coating waste: When the parts are taken out, a large amount of coating will drip, resulting in coating waste. And the dripping coating needs to be recycled, increasing the cost and treatment difficulty.
2. Problems of sagging and bubbles: If the speed and angle of taking out the parts are not appropriate, sagging phenomena are likely to occur on the surface of the coating. At the same time, during the dipping process, air may remain inside the parts, forming bubbles and affecting the quality of the coating.
3. Limited application range: For some large-sized, complex-shaped, or objects with special structures, dipping may not be able to completely cover them, or it will cause the coating to accumulate too much in some parts.

 

Application Scenario Analysis of Different Construction Methods

Due to its flexible operation and simple equipment, brushing is often used for some small-scale and local repair work, or for coating parts with complex shapes that are difficult to be constructed by other methods. For example, during the maintenance of electronic devices, brushing is a more appropriate method when repairing the protective coating of individual components on the circuit board.

Spraying methods (including air spraying, airless spraying, and electrostatic spraying) are suitable for large-scale production and occasions with high requirements for coating quality. Air spraying is suitable for various types of coatings and objects. For some products with not particularly strict requirements for coating thickness, such as ordinary electronic product casings, air spraying is a commonly used construction method. Airless spraying is more suitable for products that require a thicker coating, such as the anti-corrosion coating of automobile chassis. Due to its high coating utilization rate and good coating quality, electrostatic spraying is often used for high-end products with high requirements for coating quality and cost control, such as electronic devices and precision instruments in the aerospace field.

Dipping is mainly suitable for the coating of small-sized and batch parts, such as electronic components and small mechanical parts. These parts have regular shapes, are easy to be immersed in the coating, and dipping can ensure that all parts of the parts are evenly coated with the coating, improving production efficiency and coating quality.

Conclusion

There are various construction methods for conformal coating materials, and each construction method has its own unique advantages, disadvantages, and application scenarios. In practical applications, it is necessary to comprehensively consider factors such as product characteristics, coating requirements, production scale, and cost, and select the appropriate construction method. With the continuous development of science and technology, the construction technology of conformal coatings is also constantly innovating and improving. In the future, more efficient, environmentally friendly, and high-quality construction methods may emerge, providing better support for the application of conformal coatings in various fields. At the same time, construction personnel also need to continuously improve their operation skills and professional knowledge to ensure that the conformal coating can play the best protective effect and improve the quality and reliability of the product.

For more about construction methods, advantages and disadvantages of conformal coating materials and application analysis, you can pay a visit to DeepMaterial at https://www.uvcureadhesive.com/ for more info.