Troubleshooting your conformal coating process: Capillary flow

Capillary flow on a circuit board due to scavengingIn conformal coating, capillary flow is where the coating pulls or runs away from areas of a PCB thus leaving a patchy finish.

Factors that causes the capillary effect are

  • Low viscosity
  • Volume of coating
  • Substrate cleanliness
  • High surface tension

However, it is possible to reduce these effects by

  • Increasing the viscosity
  • Reducing the volume of coating
  • Cleaning the board properly
  • Using a solvent-based material
  • Heating the circuit board

Read more at Conformal Coating Defects: Capillary Flow

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.


Author: nexus3c

A global resource for the Conformal Coating industry providing information, solutions, connections and advice on all areas of Conformal Coating including Conformal Coating Service, Equipment, Materials, Training, Documentation and Consultancy.

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