Moisture is the most common and destructive factor affecting PCB circuit boards. Excessive moisture significantly reduces the insulation resistance between conductors, accelerates high-speed decomposition, lowers the Q value, and corrodes the conductors. It is often observed as patina on the metal parts of PCB circuit boards.
Coating the three-proof paint on the printed circuit board and components can mitigate performance degradation caused by adverse operating environments. If this three-proof paint retains its effectiveness for a satisfactory period, such as longer than the product’s service life, it can be considered to have achieved its coating purpose.
Three anti-paint composition:
Acrylic products
Acrylic tri-proof paint is flexible and offers comprehensive protection. Being a one-component system, it has good adhesion, simple application, low equipment and condition requirements, convenient construction, high transparency, high brightness, and a short operation cycle. Consequently, it is easy to use and remove. Some acrylic products meet military standards, dry quickly without requiring additional drying time, and can be removed with appropriate organic solvents. Therefore, this type of circuit board tri-proof paint is one of the most versatile and effective products available.
Is the three anti-paint toxic?
The toxicity of three-proof paint depends on the type of thinner and solvent used. If the paint uses toluene or xylene as a thinner, these chemicals are harmful to human health. Conversely, paints using lipids, alcohols, etc., are less toxic.
Despite the availability of many environmentally friendly three-proof paints, protective measures and gas masks should still be used during application.
There are four primary three anti-coating processes:
1. Brushing – universally applicable and can produce excellent coating effects on smooth surfaces.
2. **Spraying** – The use of spray cans is suitable for maintenance and small-scale production. Spray guns are better suited for large-scale production, though both methods require precise operation and may result in shadowing (areas where the lower parts of components are not covered by the protective paint).
3. **Automatic Dip Coating** – Dip coating ensures complete film coverage and avoids material waste from overspray.
4. **Selective Coating Film** – Selective coating is precise and minimizes material waste, making it ideal for large batches. However, it requires more advanced coating equipment. This method is most suitable for high-volume laminating. Using an XYZ program can reduce masking. When coating PCBs, there are often connectors that do not require paint. Adhesive paper is too slow and leaves excess glue when removed. Consider creating a custom cover based on the shape, size, and position of the connectors, using mounting holes for accurate placement to protect areas that should not be painted.
**Three Anti-Paint Operation Process Requirements**
1. **Clean and Bake the Board** – Remove moisture and contaminants from the board by cleaning thoroughly. Dust, moisture, and oils must be removed to maximize the protective effect of the three-proof paint. Proper cleaning ensures that corrosive residues are eliminated, allowing the paint to adhere well to the circuit board. Drying conditions: 60°C for 10-20 minutes. Apply the paint while the board is still warm for optimal results.
2. **Apply by Brushing Method** – The brushing area should be larger than the device’s footprint to ensure complete coverage of both the device and the pad.
3. **Brushing Technique** – Ensure the board is as flat as possible during brushing. There should be no drips, and the brushing should be smooth with no exposed areas, ideally with a thickness between 0.1-0.3mm.
4. **Preparation of Paint** – Before brushing or spraying, ensure the diluted product is thoroughly mixed and let it sit for 2 hours. Use a high-quality natural fiber brush for manual application, or measure paint viscosity with a viscosity cup if using machinery. Adjust viscosity with thinner as needed.
5. **Immersion Process** – Immersion should be vertical. Connectors should be covered carefully and not immersed. Immerse the circuit board for 1 minute until bubbles disappear, then slowly remove it. Most paint residue should flow back into the dipping machine. Immersion speed should be controlled to prevent excessive bubbling.
6. **Post-Dipping** – If skinning occurs on the surface after dipping, remove it before continuing to use the paint.
7. **Curing** – After brushing, place the board flat on a support for curing. Use heating to accelerate curing. If the coating is uneven or contains bubbles, place the board in a high-temperature oven to cure longer at room temperature to allow the solvent to evaporate.
**Precautions**
1. **Coating Thickness** – For a thicker coating, apply two thin layers, allowing the first layer to dry completely before applying the second layer.
2. **Non-Coated Areas** – Avoid coating general connectors, software sockets, switches, heat sinks, heat dissipation areas, and plug-in areas. Use a tearable solder mask to cover these areas.
3. **Film Thickness** – The thickness of the film depends on the application method. A higher amount of thinner results in a lower viscosity and a thinner coating, whereas a lower amount results in a thicker coating.
4. **Environmental Conditions** – Perform all coating operations at temperatures no lower than 16°C and relative humidity below 75%. PCB materials can absorb moisture, which can affect the protective performance of the paint. Pre-drying and vacuum drying can help remove most moisture.
**Repairing Coated Devices**
To repair a coated device, use a soldering iron to carefully remove the coated PCB component. After installing the new component, clean the area with a brush or solvent, then dry it before reuse. Ensure the paint application is performed correctly.
Coating the three-proof paint on the printed circuit board and components can mitigate performance degradation caused by adverse operating environments. If this three-proof paint retains its effectiveness for a satisfactory period, such as longer than the product’s service life, it can be considered to have achieved its coating purpose.
Three anti-paint composition:
Acrylic products
Acrylic tri-proof paint is flexible and offers comprehensive protection. Being a one-component system, it has good adhesion, simple application, low equipment and condition requirements, convenient construction, high transparency, high brightness, and a short operation cycle. Consequently, it is easy to use and remove. Some acrylic products meet military standards, dry quickly without requiring additional drying time, and can be removed with appropriate organic solvents. Therefore, this type of circuit board tri-proof paint is one of the most versatile and effective products available.
Is the three anti-paint toxic?
The toxicity of three-proof paint depends on the type of thinner and solvent used. If the paint uses toluene or xylene as a thinner, these chemicals are harmful to human health. Conversely, paints using lipids, alcohols, etc., are less toxic.
Despite the availability of many environmentally friendly three-proof paints, protective measures and gas masks should still be used during application.
There are four primary three anti-coating processes:
1. Brushing – universally applicable and can produce excellent coating effects on smooth surfaces.
2. **Spraying** – The use of spray cans is suitable for maintenance and small-scale production. Spray guns are better suited for large-scale production, though both methods require precise operation and may result in shadowing (areas where the lower parts of components are not covered by the protective paint).
3. **Automatic Dip Coating** – Dip coating ensures complete film coverage and avoids material waste from overspray.
4. **Selective Coating Film** – Selective coating is precise and minimizes material waste, making it ideal for large batches. However, it requires more advanced coating equipment. This method is most suitable for high-volume laminating. Using an XYZ program can reduce masking. When coating PCBs, there are often connectors that do not require paint. Adhesive paper is too slow and leaves excess glue when removed. Consider creating a custom cover based on the shape, size, and position of the connectors, using mounting holes for accurate placement to protect areas that should not be painted.
**Three Anti-Paint Operation Process Requirements**
1. **Clean and Bake the Board** – Remove moisture and contaminants from the board by cleaning thoroughly. Dust, moisture, and oils must be removed to maximize the protective effect of the three-proof paint. Proper cleaning ensures that corrosive residues are eliminated, allowing the paint to adhere well to the circuit board. Drying conditions: 60°C for 10-20 minutes. Apply the paint while the board is still warm for optimal results.
2. **Apply by Brushing Method** – The brushing area should be larger than the device’s footprint to ensure complete coverage of both the device and the pad.
3. **Brushing Technique** – Ensure the board is as flat as possible during brushing. There should be no drips, and the brushing should be smooth with no exposed areas, ideally with a thickness between 0.1-0.3mm.
4. **Preparation of Paint** – Before brushing or spraying, ensure the diluted product is thoroughly mixed and let it sit for 2 hours. Use a high-quality natural fiber brush for manual application, or measure paint viscosity with a viscosity cup if using machinery. Adjust viscosity with thinner as needed.
5. **Immersion Process** – Immersion should be vertical. Connectors should be covered carefully and not immersed. Immerse the circuit board for 1 minute until bubbles disappear, then slowly remove it. Most paint residue should flow back into the dipping machine. Immersion speed should be controlled to prevent excessive bubbling.
6. **Post-Dipping** – If skinning occurs on the surface after dipping, remove it before continuing to use the paint.
7. **Curing** – After brushing, place the board flat on a support for curing. Use heating to accelerate curing. If the coating is uneven or contains bubbles, place the board in a high-temperature oven to cure longer at room temperature to allow the solvent to evaporate.
**Precautions**
1. **Coating Thickness** – For a thicker coating, apply two thin layers, allowing the first layer to dry completely before applying the second layer.
2. **Non-Coated Areas** – Avoid coating general connectors, software sockets, switches, heat sinks, heat dissipation areas, and plug-in areas. Use a tearable solder mask to cover these areas.
3. **Film Thickness** – The thickness of the film depends on the application method. A higher amount of thinner results in a lower viscosity and a thinner coating, whereas a lower amount results in a thicker coating.
4. **Environmental Conditions** – Perform all coating operations at temperatures no lower than 16°C and relative humidity below 75%. PCB materials can absorb moisture, which can affect the protective performance of the paint. Pre-drying and vacuum drying can help remove most moisture.
**Repairing Coated Devices**
To repair a coated device, use a soldering iron to carefully remove the coated PCB component. After installing the new component, clean the area with a brush or solvent, then dry it before reuse. Ensure the paint application is performed correctly.
