When thinking about a conformal coating’s physical properties then I always consider that there are three states.
They are the properties during the:
- Liquid Stage (When the conformal coating is a liquid ready for production).
- Process Stage (During the conformal coating process).
- Dry Stage (When the conformal coating has dried and or cured).
The key properties will vary depending on which state you are looking for.
For example, for the liquid state the critical properties for the conformal coating include:
- Flash point
- Storage lifetime
- Appearance and colour
- Solids content
These properties are important for the conformal coating process and completely influence the outcome of the production line.
However, for the process state the critical properties the conformal coating exhibits include:
- Wet Film Thickness
- Surface Tension
- Pot life
- Drying and curing
These properties of the conformal coating material will again influence the final outcome.
Finally, for the dry state the critical properties of the conformal coating include:
- Abrasion Resistance
- Chemical Compatibility and Resistance
- Coefficient of Thermal Expansion
- Corrosion Resistance
- Edge Loss
- Fungus Resistance
- Glass Transition Temperature
- Hydrolysis Stability
- Refractive Index
- Temperature Gradient
- Thermal Shock
- Thermal Stability
- UV Stability
Note, there are a lot of physical properties but many not be important to you.
Also, most of these physical properties may be defined by the manufacturer and contained on a data sheet.
However, many other properties may be required and you may need to test.
To find out more click key physical states for conformal coating.
Or Contact Nexus now and let us show you how we can help you.
Dr Lee Hitchens is the Author of the Nexus eBook and a main contributor to Nexus.