19August, 2021An automated selective coating system is the ideal choice for medium-to-high volume production of PCBs where accuracy, repeatability, and minimal operator handling is required. The system's selective application ability will greatly reduce or eliminate the need to use masking materials to achieve the desired results. Eliminating the necessity for masking reduces the cost of labor and materials used in the manufacturing process. Additionally, since the coating is only applied where needed on the PCB, there is very little waste of the coating chemical lost to overspray beyond the PCB or target areas. These efficiencies in material and labor usage all amount to an increased return on investment (ROI).Once the liquid has been applied to the PCB, the coating is cured to create a solid, protective layer. Curing can be accomplished by various methods such as heating, exposure to moisture, high-intensity ultraviolet light, solvent evaporation, or chemical reaction. There are numerous types of coatings available, including acrylic, silicone, epoxy, and urethane. Each coating material has its strengths and weaknesses and should be evaluated prior to designing into a product specification.Selective conformal coating equipment has evolved from simple XYZ robots using a single spray valve into multi-axis, multi-head systems with many integrated features. The use of vision systems, flow monitoring, spray pattern measurement, viscosity control, and fluid metering are often integrated into automated systems to ensure coating results remain stable and consistent. Electronics manufacturers have the choice of running the process either offline in a standalone configuration or integrated with their existing electronics production line. Coating machines can also be connected to factory information systems to track useful production metrics such as machine uptime, errors, coating usage, or any other data point relevant to the process used at the factory site.Providers also offer tools used beyond the conformal coating process. Alongside the conformal coating system, equipment such as curing ovens, cleaning, and inspection systems can be delivered as a comprehensive package with all the means required to provide a repeatable and stable manufacturing process.When evaluating a conformal coating process for electronic assembly, several factors should be considered early in the design to avoid future issues. For example, a PCB that is used in an automotive environment will need to withstand broader temperature changes than a PCB used in a child's toy. There is an abundance of material choices and processing methods, and there is no one-size-fits-all solution that is suitable for all end-use environments. Designers and Production Managers should perform due diligence to fully understand the equipment, application, and material guidelines prior to implementing a conformal coating process.No matter the product or device, if there are electronics involved, it is paramount to ensure they are protected from the environment. Conformal coating is currently the most widely adopted solution. A properly deployed selective conformal coating process has been proven to lower manufacturing costs and reduce variation between coated assemblies while offering high-level traceability and flexibility, ultimately saving the manufacturer time and money. Each coating material has its strengths and weaknesses and should be evaluated prior to designing into a product specification
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