Conformal coating is a thin, transparent polymer coating applied to the surfaces of PCBs for protection. Depending on the application, this coating can serve various purposes. For instance, it can extend the service life of solder deposits of lead-free modules. Coating prevents the following, among other things: Leakage currents and short-circuits due to moisture and contamination, Corrosion, Arcing and corona discharge, Damage due to mechanical shocks and vibrations.
The selective coating system by pb tec features a special paint fi lm process that enables application of the protective paint without contact and without additional masking or demasking work. Also, it is no longer necessary to clean surfaces that should not come into contact with the protective paint. The main benefits of this fully automatic process are: Reliability and repeatable results, Increased productivity – higher throughput and lower labour costs, Better use of materials and thus also savings on materials, Significant improvements in quality.
The PCBs are coated with the paint film process under low pressure selectively and without atomised spray, and therefore with extremely high precision without atomisation. The coating material is taken from a paint feed system that works under pressure. Thanks to the paint curtain, there is no overspray. The coating speed is up to 1000 mm/s. The surface area to be coated can be easily teached-in with an operator-actuated Joystick control. Depending on the application requirements, special coating heads are available for various painting processes.
The coating system can be optimally configured to the specific product requirements through various options, such as an internal turning station, fluid monitoring, coating-width check, etc. Common coatings used for the protection of printed circuit board assemblies and complete units: Polyurethane resins, Acrylic Resins, Epoxy resins, Acrylate resins, Silicone Casting Compounds.
The Rehm RDS dryers are suitable for using with all common coatings used for the protection of printed circuit board assemblies and complete units. All heating chambers are equipped with powerful IR radiators. To protect against contamination and to facilitate cleaning, all IR radiators are provided with glass covers on the bottom heating section. This reduces maintenance and extends the lamp life significantly. In addition, the drying process is supported by central convection heating. The flow rate can be preset for each zone. The excellent thermal insulation of the heating zones and the individually adjustable temperatures make it possible to tailor the drying process according to particular specifications.
Here you’ll find more interesting information – see the interview with Michael Hanke Chief Customer Officer of Rehm Thermal Systems at SMT 2012:
Rehm interview
