What is discolouration of a conformal coating and why does it occur?

Discolouration is when there is a change in the color or loss of transparency of the conformal coating.

This defect adversely affects the performance or the identification of the components covered by the coating.

Factors that cause discolouration can include:

  • UV light exposure
  • Contamination
  • Time on the circuit

Some ways to prevent discolouration from occurring are:

  • Eliminating the UV light
  • Applying the correct coating
  • Ensuring a clean environment

Read more on Conformal Coating Defects: Discolouration

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What are the important material physical properties critical to processing?

Conformal coatings have different physical properties that are that define the quality of the coating coverage. These qualities include:

  • Wetting
  • Capillary
  • Viscosity
  • Wet film thickness
  • Surface tension
  • Pot life
  • Drying and curing

Read more on Conformal Coating Physical Properties: Processing

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.

Production Key stages: De-masking

De-masking is the process of removing the masking that leads to the next stage of Finishing.

Some factors that damage the conformal coating finish due to the de-masking process include:

  • Masking removal when the tapes etc are removed
  • Shadowing effects preventing coating reaching the right areas.
  • Quality of coating being not up to standard
  • Masking leakage where the coating has bled under the masking materials.

The amount and type of finishing required depends on several factors such as:

  • Standards
  • Work instructions
  • Coating defects
  • Operator skill
  • Degree of cure

Read more on Conformal Coating Processing: De-Masking and Finishing

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.

Troubleshooting: Fisheyes

fisheye defects found on a conformal coated circuit boardFisheyes is a localized de-wetting defect that looks like craters on the surface of the conformal coating.

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.

What are the organic conformal coatings?

Organic conformal coatings have principal ingredients that come from animal, vegetable, or a compound of carbon.

Organic conformal coatings can be subdivided into resin types such as:

  • Acrylic (AR)
  • Polyurethane (UR)
  • Epoxy (ER)
  • Acrylic Urethane Blend (ARUR)

Read more at Classification of Conformal Coating: Organic

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.

What are the critical electrical Properties of a conformal coating?

Conformal coatings have different electrical properties that is dependent on the chemical composition of the coating.

These electrical properties include:

  • Dielectric constant
  • Dissipation factor
  • Dielectric withstand voltage
  • Insulation resistance
  • Moisture insulation resistance
  • Q resonance

Read more at Conformal Coating Electrical Properties: Overview

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.

The many Physical Properties that are important in a conformal coating when dry

Coated board Close UpIt is in the dry state when the conformal coating reaches its full potential for its physical properties.

The important physical properties of the coating include:

  • Abrasion resistance
  • Chemical compatibility
  • Chemical resistance
  • Coefficient of thermal expansion
  • Corrosion resistance
  • Edge loss
  • Film thickness
  • Flammability
  • Flexibility
  • Fungus resistance
  • Glass transition temperature
  • Hydrolysis stability
  • Out gassing
  • Permeability
  • Refractive index
  • Temperature gradient
  • Thermal shock
  • Thermal stability
  • UV stability

Read more at Conformal Coating Physical Properties: Dry State

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.