What is Conformal Coat

By Bester PCBA

Last Updated: 2023-11-06

What is Conformal Coat

A conformal coat is a protective polymer film that is applied to a pcb assembly to safeguard it against chemical damage and environmental factors. Using conformal coatings enhances the reliability and longevity of the PCBA by creating a barrier between the board and potential contaminants.

The main benefit of applying a conformal coat is moisture protection. Moisture can lead to issues such as short circuits, corrosion, and degradation of electrical performance. By applying a conformal coat, the PCBA is shielded from moisture, reducing the risk of these problems.

Conformal coatings also serve to protect the PCBA from exposure to corrosive substances. These substances can be present in the environment or may come into contact with the PCBA during its operation. The conformal coat acts as a barrier, preventing the corrosive substances from reaching the sensitive components of the PCBA and causing damage.

Additionally, conformal coatings modify the dielectric strength in the layer surrounding the board, providing protection against electrostatic discharge (ESD). ESD can occur when there is a sudden flow of electricity between objects with different electrical potentials, and it can damage electronic components and affect the overall functionality of the PCBA. The conformal coat helps dissipate the electrical energy from an ESD event, reducing the risk of damage.

Conformal coatings are particularly crucial in industries that require components to withstand extreme conditions, such as the aerospace industry. However, with the advancement of technology and the widespread use of electronic devices, the conformal coating process has become commonplace in many applications, including those used by the general public, such as mobile devices.

Frequently Asked Questions

What Is the Difference Between Silicone and Acrylic Conformal Coating

When it comes to conformal coating types, there are some differences between acrylic and silicone coatings. While acrylic coatings are known for their hardness, silicone coatings are more flexible and offer better mechanical shock resistance. Additionally, silicone coatings are designed to withstand harsher service environments, have better liquid water repulsion, and offer better chemical resistance. Overall, silicone coatings are soft, yet tough and durable, making them a great choice for a variety of applications.

What Causes Bubbles in Conformal Coating

Bubbles in conformal coating are caused by the entrapment of solvents or air within the coating material. These bubbles can result in various long-term problems with product reliability, such as the formation of conductive path bridges, corrosion of exposed areas, and cracking of the coating due to temperature fluctuations, shock, or vibration.

Is Conformal Coating Necessary

It is crucial to use conformal coating on your PCBs to safeguard them against harmful environments and contaminants. Moisture can accelerate decomposition, lower insulation resistance, and lead to conductor corrosion, making conformal coating an essential protective measure.

How Thick Is Conformal Coating PCB

Commonly, the thickness of conformal coating on a PCB ranges from 1 to 5 mils (25 to 127 microns), and in some cases, it can be even thinner. If the coating exceeds this range, it is likely to be an encapsulate or a potting compound, which offers greater mass and thickness for enhanced board protection.

Can You Solder Through Conformal Coating

It is feasible to solder directly through conformal coatings and Parylene coating in order to remove them. Typically, the resulting finish is deemed satisfactory.

What Causes Orange Peel in Conformal Coating

The issue of orange peel in conformal coating is primarily observed when solvent borne conformal coatings such as acrylics, urethanes, and synthetic rubbers are used. This is due to the uneven drying that occurs on the surface of the coating.

How Do You Protect PCB From Corrosion

One effective method to safeguard a PCB from corrosion is by applying a protective coating on the exposed copper sections. Various types of coatings, such as epoxy coatings, aerosol spray coatings, and solder masks, can be utilized for this purpose. Additionally, it is crucial to minimize the presence of humidity around the PCBs.

What Is the Difference Between Conformal Coating and Potting

A conformal coating is generally thinner, ranging from 25 to 250 microns, which makes it a lighter alternative compared to PCB potting. Additionally, it occupies less space. Conformal coating offers effective protection against potential risks like corrosion and particulate matter. Moreover, it also provides waterproofing capabilities to safeguard against moisture.

What Is the Difference Between Conformal and Non Conformal Coating

Conformal coating provides protection to the board while allowing for convenient board repairs. On the other hand, a non-conformal coating, also known as potting or encapsulating, is significantly thicker than a standard conformal coat.

Does Conformal Coating Protect Against Water

While conformal coatings can provide a layer of protection against moisture, it is important to note that they are not completely waterproof. Most coatings are semi-permeable, meaning they allow some moisture to pass through. However, conformal coating can effectively prevent current leakage and corrosion caused by ambient moisture.

What if Conformal Coating Is Too Thick

Excessively thick conformal coatings can lead to residual stress, which may result in damage to the electronic device being coated. In such cases, it is necessary to address the issue by either removing and reapplying the coating or grinding it down. The appropriate method to be employed will vary depending on the specific type of coating being used.

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