As vehicle sales continue to grow in the US, increasing 1.7% from 2013 to 2014, so does the variety of electronics that keep cars safer, make them more interactive, and let them stay on the road for longer periods of time. In addition to meeting general safety requirements and regulations, many of the features once reserved for luxury vehicles now come standard, putting a strain on automotive manufacturers as they struggle to keep space and weight to a minimum while incorporating an ever-growing list of electronics-based applications. These concerns will only increase as emerging technologies like rear-facing cameras, automatic parking, and self-driving cars dominate the automotive manufacturing industry.
As car companies pack more and more electronics into vehicles, board real estate becomes a premium, paving the way for conformal coatings instead of enclosures to protect circuitry. (Source: Dymax)
Protecting the circuit boards inside these applications is a constant challenge. From internal heat fluctuations and vibration to outside contaminants like salt and dust, vehicles are harsh environments for sensitive electronics.
Traditional approaches like building individual enclosures or potting the PCBs keep harmful elements away but consume critical space and weight inside the vehicle. Light-curable conformal coatings help automotive manufacturers maximize space and minimize excess weight while safeguarding sensitive boards from harmful elements both inside the vehicle and on the roads.
As with any design, specific requirements, board complexity, environmental conditions, and other factors may impact performance, but conformal coatings are and have been a viable alternative to other solutions like enclosures and potting for protecting and insulating electronics for the lifetime of the vehicle. There is also MIL-spec testing and UL testing to help characterize performance.
Starting at initial application, conformal coatings are highly customizable. Whether brushed on, flow coated, or applied by automated spray, the thickness of the coating can be adjusted for each board’s requirements. However, even with thicker applications, conformal coating offers a big advantage over other options: no enclosures. This means more boards can fit into a single space, leaving room for other critical components.
Typically ranging between .002 to .005 inches, conformal coatings are thin but highly effective. Not only do they protect PCBs from damaging conditions and contaminants, they electrically insulate the components from environmental stresses. This can help lengthen the electronics’ lifespan and improve its overall performance. Conformal coatings can also slow the growth of tin whiskers, which develop on electronics over time, helping to prevent arcing and short circuits.
Before they’re even applied to electronics, light-cure conformal coatings can help manufacturers save space and lower costs. The non-hazardous materials are less expensive to ship and, as single compounds, do not need mixing as required with two-part epoxies. Light-curing equipment often takes up less manufacturing floor space than other electronics protection methods and is an easier process overall to automate.
Like our mobile devices, automotive electronics are growing more advanced and complex while simultaneously shrinking in size and weight. Consumers demand a connected experience inside their vehicles, adding to the already staggering list of standard features requiring boards like power windows and doors and automatic transmissions.
As new technologies continue to emerge, it will become increasingly critical to minimize weight while maximizing the space for connected applications and safety requirements with light-cure conformal coatings.
Here are additional tips for selecting the right conformal coating, thickness, and curing shadowed areas.
Tony Ieraci is Global Communications Manager for Dymax Corp., which offers oligomers, adhesives, coatings, and cure and dispense equipment.