What are the critical physical properties for a conformal coating when dry?

Sticking conformal coating reduced sizeThe physical conformal coatings properties can be subdivided into three key areas.

These are:

  • Liquid
  • Process
  • Dry State

They can be further subdivided into many different individual properties dependent on the type of chemistry of the coating.

Dry State

Once the conformal coating is applied and is fully dried / cured then it will have reached its full potential physical properties. This is the dry state.

Critical properties include:

  • Edge Loss
  • Refractive Index
  • Glass Transition Temperature
  • Coefficient of Thermal Expansion
  • Temperature Gradient
  • Flammability
  • Flexibility
  • Abrasion Resistance
  • Hydrolysis Stability
  • Permeability
  • Chemical Compatibility and Resistance
  • Corrosion Resistance
  • Fungus Resistance
  • UV Stability
  • Outgassing
  • Thermal Stability
  • Thermal Shock

Click to find out more on the dry state properties of conformal coatings.

 

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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.

What are the important physical properties of a conformal coating in production?

Conformal coating is composed of different physical properties. One of which is liquid. The liquid properties need to be defined prior to the conformal coating.

The properties include flash point, storage lifetime, appearance and colour, density, solids content, and viscosity.

Liquid properties overview:

  • Flash point: the temperature needed for an organic compound (solvent) to release enough vapour in the air
  • Storage lifetime: shelf life of the conformal coating
  • Appearance and colour: mostly clear
  • Density: measured by a pycnometer
  • Solids content: non-volatile material that remains after the coating is done
  • Viscocity: showing the internal friction in a fluid resisting flow

Read more at Conformal Coating Physical Properties: Liquid

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 Conformal Coating Contamination

 

Contamination on the circuit board on top of the conformal coatingContamination happens when debris is trapped or found on the conformal coating of the printed circuit board. This can affect the reliability of the board over time.

Origin of Contamination:

Contamination can occur during the following situations:

  • Pre-production stage
  • Processing stage (during application)
  • Drying or curing stage
  • During the lifetime of the product

Preventing Contamination:

Contamination during the conformal coating process can be avoided by:

  • Improving cleanliness prior to production.
  • Having an efficient cleaning process prior to conformal coating.
  • Ensuring a safe and effective process after the coating.

Read more at Conformal Coating Defects: Contamination

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 Chemistry of a conformal coating

Conformal coating is comprised of two significant parts namely the volatile and non-volatile materials.

The volatile materials can be further broken down into two sections: the solvents and the additives.

The non-volatile materials also comprise of two components namely the binders, which are comprised of resins and additives, and the colorants.

The powder-like material that is used to improve the properties of coatings is called the Filler. It is also used to even out the coating where irregularities in substrates are found when ready to be painted.

Each type of conformal coating has its own physical and electrical properties. It varies in both the wet and dry state thus enabling the user flexibility in selecting the type of conformal coating to be applied.

Read more at The Chemistry of a Conformal Coating

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.