Rohde & Schwarz:
Sophisticated pretreatment solutions for the avionics industry
Pretreating highly sensitive avionic SMD assemblies with plasma prior to conformal coating
As the world's leading provider of wireless communications and EMC test and measurement equipment as well as broadcasting and T&M equipment for digital terrestrial television and manufacturer of aircraft radio systems for long-haul flights, we are required to meet the highest safety standards in the manufacture of our electronic products.
At the core of our aircraft radio antenna tuner is a circuit board fitted with several hundred individual surface-mounted devices. Openair® plasma was integrated into the production line for these SMD assemblies when a problem with the adhesion of the conformal coating unexpectedly arose. The composition of the plastic blend used in some plastic-encapsulated assemblies had been modified by the supplier, rendering the surface energy of the plastic no longer sufficient to ensure adhesion of the protective coating.
The use of Plasmatreat technology immediately rectified the problem. Preliminary tests using an Openair® plasma system on loan from the company verified the claim that the plasma was virtually potential-free: the highly sensitive electronics were not damaged in the slightest by the plasma radiation. In unactivated state, the surface tension of the plastic-encapsulated assemblies was below 30 mN/m, but this rose to over 70 mN/m following plasma treatment. The burn-in test, which is regarded as the toughest stress test available for electronic SMD assemblies, was passed with flying colors.
We established a good working relationship with Plasmatreat right from the outset, and are very satisfied with the technology and level of service. As regards the process itself, we particularly appreciate the high process reliability and reassuring monitoring function. These two factors, combined with the fact that the system is very easy to use, have convinced us of its benefits. Openair® plasma technology has enabled us not only to reduce the number of process steps, but also to enhance the quality of our product within a very short space of time. The project has been a resounding success.
Rohde & Schwarz
Dipl.-Ing. (FH) Michael Schneider
Department of Manufacturing Technology
Rohde & Schwarz Messgerätebau GmbH