One- and two-component potting compounds are used very frequently. With two-component potting compounds, resin and hardener are mixed in a specific ratio using appropriate machinery and, as standard, poured into the cavity via a static mixing tube. Thus, this cold potting is a non-molding process and requires a housing into which the potting compound is poured.
Potting potting offers many advantages: Not only does it provide excellent electrical insulation, high heat dissipation, and vibration and shock reduction, but it also offers resistance to chemicals, moisture, thermal shock, and cycling; protects electronics from dust and moisture; and possesses flame-retardant properties.
 
Depending on specific requirements, epoxy, polyurethane, and silicone resins are typically used. They all differ in terms of their properties (Table 1). 

conformal coating is used to coat printed circuit boards either completely or selectively. In the case of selective plating, only the necessary areas of the printed circuit board are covered with a protective layer. Generally, a distinction is made between two types of coating: Thin-film coating, with its fast curing time and optimized viscosity, ensures high cost-effectiveness in manufacturing processes. In contrast, thick-film coating provides particularly high edge and surface protection, safeguarding electronic assemblies especially against extreme humidity. In both cases, the conformal coatings build up layer thicknesses of only 30–2,000 µm after drying. This means the electronic assembly can still be installed even in tight spaces.  

Due to the varying viscosities of the conformal coatings—and thus their differing flow characteristics—the DAM & FILL principle is frequently applied to assembled electronic assemblies. Here, a thixotropic conformal coating is used to create a “dam” around components that must not be encapsulated, such as connector. The remaining components are then coated with a low-viscosity conformal coating (“fill”). Various polymer materials are used

for conformal coating. For example, users can choose between silicone-based and UV-curing products, among others. The former are ideally suited for harsh operating conditions—such as in the aerospace or offshore industries—due to their wide temperature range of -40°C to +200°C. The latter consist of acrylates and polyurethanes or hybrids of both materials. They are characterized above all by the fact that they cure very quickly through UV initiation and offer excellent thermal shock resistance.

The applications for conformal coatings are diverse and range from the automotive sector to railway, sensor technology, industrial electronics, medical technology, as well as the aforementioned Offshore-wind power and aerospace technology.

hot-melt molding is a special form of potting. In this process, the assembly is encased in a material in a single step, creating a housing structure while simultaneously protecting the assembly. The electronics are not damaged in the process, as the low-viscosity, thermoplastic materials have a low processing temperature and are processed at a much lower injection pressure than in standard plastic injection molding. On the one hand, this protects the components; on the other, it allows the thermoplastics to cure quickly and makes the process relatively cost-effective.

Low-pressure injection molding (low-pressure molding) thus enables even sensitive components such as contacts, sensors, printed circuit boards, and coils to be encased, bonded, or sealed to IP68 standards in an environmentally friendly manner, thereby protecting them even from the most severe conditions.

One industry heavily affected by external influences is agriculture, for example. Machinery in this sector is exposed to varying weather conditions on a daily basis. hot-melt molding is perfectly suited for protecting its electronics: It provides reliable, long-lasting protection against moisture, temperature fluctuations, corrosion, and vibrations. 

Extreme temperatures, dirt, and moisture, as well as chemical or mechanical stress: With the appropriate component protection method, the electronics are shielded from nearly any external influence. However, one aspect must be considered: Potting (potting) is only possible if the functionality of the installed components is not compromised by the materials used. This also requires a connection solution that is compatible with the potting compound—therefore, the use of standard PCB connectors is not an option. The reason for this is the typically two-part spring-blade contact technology, in which the potting potting compound can penetrate the vulnerable mating area and thus interfere with the contact.

With conventional connectors, the contact area must therefore be sealed using the “dam and fill” method prior to potting to avoid any risk of interference from the potting compound (Fig. 2). The concern here is that, in the contact area, the potting compound could, on the one hand, impair the contact points and thus interrupt signal transmission. On the other hand, it would inhibit the relaxation properties of the spring.

To still allow for “potting” while ensuring the required reliability, it is recommended to choose a one-piece connection solution—that is, a connector that does not require the conventional “mating area.” With such a one-piece connector, it is impossible for the “potting compound” to penetrate the contact area.