On Wednesday the 27th of February, the section for mechanics arranged at Technical University of Denmark in Copenhagen, DTU, one half-day seminar about circuit board varnish. One of the section's institutions, Cell corr, is specialized in research into corrosion of electronics.
Speakers from various research companies and companies that sell materials, equipment and methods for protecting sensitive electronics were invited to the seminar. Tribotec product manager for silicone Tuomas Ollilainen was asked by Celcorrs Professor Rajan Ambat to come and talk about silicone-based circuit board varnishes.
The seminar attracted approximately 65 participants from Sweden and Denmark. Representatives from companies such as Danfoss, Vestas, Bombardier and Grundfos were in the audience.
Interest in protecting electronics is steadily increasing, and the big companies are joining the trend. In the past, designers in both Sweden and Denmark have focused a lot on IP classifications, i.e. the idea has been to make a seal around the electronics so that you don't have to paint or cast the electronics in any protective material. But as Jens Peter Krog from Grundfos proved in his presentation: all polymers let moisture through, it's just a matter of time. Thus, even the highest IP classification, IP67, does not help more than briefly. The realization of this has started to sink in with the industry quite recently.
Judging by the talk afterwards, many were very satisfied with the information presented during the seminar. Despite the fact that several of the speakers represented competing companies, there was no significant debate about the pros or cons of the various alternatives. Everyone seemed to know that silicone provides very good protection, but that it costs slightly more than e.g. acrylate varnishes.
The only time it got a little heated was when Tuomas Ollilainen said that washing the circuit boards was not necessary before painting with silicone varnish. This was agreed by other representatives of protective materials, but Professor Rajan Ambat interjected that their research shows that no material provides a 100 % protection unless you wash away flux residues. However, to wash or not to wash is a rather controversial issue. DTU only washes with isopropanol, but many industrial washes also include detergents, and then there is the risk that residues of detergent remain on the cards, which can therefore introduce a new problem when you wanted to get rid of another one. At the same time, it can be stated that DTU has a very high level of methodology in its research, and it is possible that at that level you can find differences between washed and unwashed cards.
