Conformal Coating Protect PCBs From Environmental Factors
The use of conformal coating on PCBs can help prevent damage from environmental factors, which in turn reduces the cost of repairs and replacement parts. Conformal coating also increases the durability of the boards and keeps them functioning as intended for longer periods of time. These benefits are especially important for mission-critical devices or those that must operate in a particular environment.
How does conformal coating protect pcb from environmental factors? Conformal coating is typically applied in a liquid form and comes in a variety of thicknesses, from very thin to quite thick. This means that there are different options for what type of conformal coating to use on a circuit board, depending on the operating conditions that it must endure. For example, an aircraft-mounted electronic will need a conformal coating that can withstand extreme temperatures. This may necessitate the use of a silicone conformal coating instead of a polyurethane conformal coating, as silicone has better temperature resistance capabilities.
Other environmental factors to consider include moisture and corrosive chemicals. Moisture can cause problems for electronics by causing oxidation, which in turn leads to electrical short circuits. Conformal coatings can help prevent this by providing a protective barrier that stops water molecules from reaching the components and causing corrosion. Similarly, corrosive gases can be problematic for electronics, so conformal coating is often used to protect against them as well. Conformal coating can be resistant to a number of different gases, including carbon monoxide, hydrogen sulfide, and sulphur dioxide.
How Does Conformal Coating Protect PCBs From Environmental Factors?
In addition to protecting against corrosion and environmental damage, conformal coating can also help a circuit board withstand high levels of heat. Conformal coating can be used to protect both the substrate and solder connections of a circuit board, helping it maintain its structural integrity even when subjected to high temperatures.
The thickness of the conformal coating that is used on a circuit board can affect its performance, with thicker conformal coatings having a slower curing time than thinner conformal coatings. It is important to make sure that the coating is applied to a specified thickness, as over-application can lead to issues such as stress shrinkage or cracking.
Before conformal coating is applied, it is necessary to ensure that the circuit board surface is clean and free of any debris that could interfere with the adhesion of the coating material. This is particularly important when using spray-based coatings, as debris can lead to a discoloration of the coating or create physical defects on the surface. One common adhesion problem is known as “fish eyes” and occurs when little craters or holes develop on the conformal coating, often caused by the coating being applied unevenly.
It is also essential to note that conformal coatings are not waterproof, and the resulting moisture can still cause a range of issues for the circuit board. In fact, if the moisture is trapped on a circuit board for extended periods of time, it can actually cause the coating to delaminate. To prevent this, it is helpful to mask areas of the circuit board that should not be coated, or to use a gel material to create a dam to contain the coating and avoid capillary effects transferring the conformal coating to unintended locations.
