I'm having trouble selecting a chem film class. I'm designing an avionics box that basically operates in a marine environment and is safety critical equipment. Type I is not an option for us (environmental restrictions), so I intended to callout Type II, Class 1A. There were concerns with electromagnetic compatibility so there is a desire to go with Class 3 for lower electrical resistance.
I don't quite understand the corrosion protection differences between these two classes.
My supplier is saying that their chem film (Chemeon TCP-HF) meets both class 1A and 3. Other supplier websites say Class 1A offers better protection since it has a thicker coat, meanwhile Class 3 is a thinner coat. My thinking is that a thinner coat would be susceptible to marring, scratches, dents, etc. damaging/removing the protective coating and negatively affecting product longevity. I think Class 1A is the way to go here, even with the EMC requirement.
Is this a valid concern for class 3?
Is there any evidence for failing DO-160G EMC tests with Class 1A coatings?
Any suggestions? Am I being too pedantic?
I don't quite understand the corrosion protection differences between these two classes.
My supplier is saying that their chem film (Chemeon TCP-HF) meets both class 1A and 3. Other supplier websites say Class 1A offers better protection since it has a thicker coat, meanwhile Class 3 is a thinner coat. My thinking is that a thinner coat would be susceptible to marring, scratches, dents, etc. damaging/removing the protective coating and negatively affecting product longevity. I think Class 1A is the way to go here, even with the EMC requirement.
Is this a valid concern for class 3?
Is there any evidence for failing DO-160G EMC tests with Class 1A coatings?
Any suggestions? Am I being too pedantic?
