These are normally caused by a contaminant that was present on the surface before the conformal coating application.
Cleaning the surface of the circuit board is crucial in preventing the fisheye defect.
Read more on Conformal Coating Defects: Fish Eyes
Who is Nexus?
Nexus brings together the accumulated knowledge of a group of conformal coating and electronics material dispensing consultants who provide a unique service, focused on helping electronics manufacturing clients improve their conformal coating and electronics materials processes.
Nexus operate across North America, Europe and Asia and can provide a unique perspective to the rapidly growing conformal coating and electronics materials industry. Expertise is held in liquid and parylene coating, capital equipment sales and specifications and material, equipment and process specification, troubleshooting and training.