A conformal coating is a thin film which “conforms” to a printed circuit board (PCB). It provides electrical insulation and protection from external conditions. Silicone, acrylic, urethane or epoxy are common materials for conformal coatings.
Conro Electronics offers a wide choice of conformal coatings from major manufacturers, such as 3M, Dymax and HumiSeal.
Conformal coatings protect electronics from extreme temperatures, water and chemicals. This extends the working life of components. The insulation allows a reduction in PCB conductor spacing.
They are used in applications requiring high performance and reliability. These include military, automotive, green energy and mobile electronic industries.
Application methods depend on volume of product and board design. Brushing is common for low volume applications. For low to medium volume applications, the coating can be sprayed onto the PCB. High volume applications often use a dipping method.
Masking is required to protect the circuit board. This ensures the coating only adheres where needed. Curing options for them include air drying, heat and UV.
Components can be reworked after the coating is applied. De-masking and removing might be required due to upgrades or production problems. Common or specialist solvents are used to remove the coating.
- Silicone: wide operating temperature range. Good chemical resistance, flexibility and resistant to sea salt.
- Acrylic: easy to use and remove. Provides fair elasticity. Abrasion resistant, has high dielectric strength.
- Polyurethane/urethane: excellent moisture and chemical resistance, abrasion resistant.
- Epoxy: good moisture resistance, high abrasion and chemical resistance.