Conformal coating is a specialty polymeric film forming product that protects circuit boards, components, and other electronic devices from adverse environmental conditions. These coatings conform’ to the irregular landscape of the PCB providing increased dielectric resistance, operational integrity, and protection from corrosive atmospheres, humidity, heat, fungus, and airborne contamination such as dirt and dust.
Techspray offers a variety of conformal coating formulas to match field and engineering requirements and is IPC CC 830B, MIL-I-46058C, and UL94-0 Qualified or rated. Specifications generally depend on the type of protection needed: e.g. thermal, moisture, and static resistance.
Coatings contain Opti/Scan (except LED Coating) to allow quality control inspection of coverage and evenness of the coating on a PCB. A coated board can be passed under a standard, low-cost UV (short-wave black) light, and the coated areas glow. The brighter the glow, the thicker the coating.
No, conformal coatings are non-conductive, or insulative. The job of conformal coating is to isolate the PCB or components from the environment and even components (i.e. high voltage or high heat) from the rest of the board. To do that properly, a coating must have electrically insulating properties with as high of a dielectric withstand voltage (or strength) as possible.
While conformal coatings can offer a moisture resistant layer of protection, most cannot be considered waterproof. Even if applied heavily, most coatings are semi-permeable, so allow some amount of moisture through. Conformal coating can, however, prevent current leakage or corrosion due to ambient moisture. To truly waterproof electronics, you either need gasketing to seal the electronics within the packaging or cover the electronics with a waterproof encapsulant or potting compound.
Whether or not conformal coating is required depends on the environment the electronic device will operate in, the reliability requirement of the device, and the cost of failure, whether in dollars or human lives. Typical consumer devices are generally not coated because cost is one of the top driving factors, and a coating step certainly adds to that. Devices operating in harsh environments may require coating, and the type of stresses and contamination will point to the best option, whether that is acrylic resin (AR), silicone resin (SR), urethane resin (UR), or some other type of protection. Aviation, aerospace, and medical devices often require coating because of the mission critical nature of these applications.
Conformal coating is a specially engineered polymeric film-forming product that protects circuit boards, components, and other electronic devices from harmful environmental conditions like moisture, thermal shock, static, vibration, and contamination. These coatings ‘conform’ to the irregular landscape of the PCB providing increased dielectric resistance, operational integrity, and reliability. There are a number of options for coating technologies, and the best option should depend mainly on the protection required. Application method and ease of rework are also important factors, but should generally be considered secondary to the protective performance needed.