Why electronic assemblies need a coating?

Conformal coatings insulate and protect the PCBs and their components from harmful environmental influences. The sensitive components in electronics are exposed to many of these influences: Therefore the assembly must be protected from abrasion, vibration or light impact loads. In case of humidity, condensation, hand sweat or various chemicals, there is a risk of corrosion or mould. One of the most important tasks of a conformal coating is the prevention of dendrite growth, which occurs under the condition of condensation or adsorbed moisture in combination with electrical voltage if no conformal coating has been applied.

The coating materials improve the electrical insulation between two potentials which is particularly important for explosion protection or for high-voltage stresses.

In order to protect electronics from electrical failures, manufacturers take all measures to ensure the function of electronic devices even under difficult conditions. This especially applies for assemblies that are built into devices for aerospace technology, medical equipment and also in automobiles (e.g. engine control, central locking, window lifter and airbag electronics and increasingly in e-mobility.

Flat modules are also installed unprotected in end devices and can run fault-free over their service life. In complex systems, however, such as the applications described above, permanent function can only be ensured if the assembled PCB is given a conformal coating.

In addition to the solder joints recessed by solder resist, different potentials are also present at the various components on the PCB, which have no shielding. Depending on the requirements, these potentials can be shielded with conformal coatings, thick-film lacquers or casting compounds.

As a full-range supplier of coating materials for electronics, Lackwerke Peters has the right products in its portfolio. ELPEGUARD® conformal coatings and top coats as well as ELPECAST® casting compounds for even more extreme conditions such as aggressive industrial atmospheres, exposure to operating fluids (e.g. fuels, oils, lubricants) are used here.

Conclusion: Only the protection against environmental influences and interfering electrical voltages enables a wide-ranging use of these products, even under extreme conditions. In the next article, we will describe what this means and what requirements are placed on coated assemblies in the electronics industry.

Please contact your Rotec sales representative for more information