Why Solids Content Matters When Costing Conformal Coating Application

August 15, 2017 conformal coating

The solids content of a conformal coating represents the proportion of material that remains on the printed circuit board once solvents have evaporated. In simple terms, solids content determines how much usable coating you actually obtain from each litre of material.

The higher the solids content, the more circuit boards can be coated from the same volume — directly impacting material efficiency and cost.

High Solids Means Real Coverage

When selecting a conformal coating, it is tempting to focus solely on the price per litre. However, this can be misleading. What truly matters is the final solids content at application viscosity, not the as-supplied specification on the datasheet.

In many cases, a large proportion of the purchased material is solvent that will evaporate during application, contributing nothing to protection.

To understand how solids content fits into overall coating selection and process design, explore our conformal coating processes hub.

Be Careful When Comparing Coating Materials

Conformal coatings from different manufacturers can vary significantly in both solids content and viscosity. These differences can lead to substantial hidden cost variations, even when products appear similar on paper.

A meaningful comparison must always consider the true solids content of the coating as applied in production, once diluted to the correct working viscosity.

A Typical Industry Example

Consider a common scenario seen across the conformal coating industry:

Material X is supplied at 35% solids with a viscosity of approximately 190 cps.
To achieve correct spray application, the coating must be reduced to around 24 cps.
This reduction requires approximately 50% dilution with solvent.

After dilution:

The coating now contains only 17.5% solids.
More than 80% of the applied material evaporates during application.

In practical terms, less than one-fifth of the purchased material contributes to actual PCB protection.

Not All Coatings Deliver the Same Value

It is incorrect to assume all conformal coatings perform — or cost — the same in real-world use.

For example, SCH supplies a UL-approved acrylic conformal coating that is 44% solids at 24 cps, supplied ready to spray without dilution.

When compared directly:

Material X: 17.5% solids at spray viscosity
High-solids coating: 44% solids at spray viscosity

The higher-solids material provides more than twice the effective coverage per litre. If both coatings are similarly priced per litre, over twice as much of the lower-solids material would be required to achieve equivalent protection.

The Takeaway

Careful evaluation of solids content at application viscosity can deliver substantial material cost savings, reduced solvent handling, and more predictable coating performance.

When costing conformal coating processes, always look beyond headline datasheet values — real efficiency is defined by what remains on the board, not what evaporates away.

Want to Calculate Your True Coating Cost?

If you would like a spreadsheet that allows you to calculate coating coverage and cost per PCB using your own process parameters, SCH can provide this directly.

If you would like a coverage and cost calculation spreadsheet or want to discuss your coating process, contact our technical team.

Requirements for setting up a conformal coating facility

July 24, 2017 Blog, conformal coating

Conformal coating application and inspection at SCH Services

The set up of a conformal coating production line regardless of the application method has many similar characteristics.

Any coating facility will need the basic requirements put in place that would be standard for any piece of electronic manufacturing process. These include ESD systems, facilities for the machines, the environmental requirements and the normal Health & Safety (HSE) considerations.

Also, the conformal coating production line, whether it is an operator manually brush coating printed circuit boards (PCBs) or an inline robotic spray coating process is typically made up of several stages. These stages are shown below:

Conformal coating process chart illustrating key stages and controls

Not all the stages are mandatory or may be required. However, each should be considered on an individual basis.

Planning to set up a conformal coating facility?

Explore our Conformal Coating Processes Hub and read the detailed guide: How to set up a conformal coating production line. The article covers equipment selection, process flow, quality control and scale-up considerations for reliable, repeatable coating operations.

Prefer to talk it through? Our engineers can review your requirements and help you plan a coating facility that fits your volumes, materials and compliance needs.

Contact SCH to discuss your conformal coating setup ›

Three key points you should know about polyurethane conformal coatings when using them for protecting electronic circuit boards

July 12, 2017 alternative, Blog, conformal coating

SCH Services UK conformal coating facility and operations

A polyurethane (urethane for short and designated UR by IPC) conformal coating is part of the organic family of coating materials that also includes the acrylic and epoxy coatings.

Here are three key facts to consider when examining polyurethane conformal coatings:

Most conformal coatings provide good humidity and moisture protection although some are slightly better in performance than others. UR type coatings are just as good on average as acrylic materials.
A polyurethane coating has traditionally been used to protect electronic circuit boards against chemical attack due to their excellent chemical resistance. This protection allows electronic circuit boards to survive in highly aggressive environments and atmospheres such as the aerospace, military and industrial sectors. However, it does make repair a little more difficult as chemical resistance to a coating means more difficult to remove.
Times are changing and whereas acrylic conformal coatings used to dominate 70-80% of the market, there is a shift in emphasis towards alternative materials due to higher specifications for protecting electronics. Many new conformal coatings (UV cure, two part thin film coatings) now comprise of urethane resin bases and are becoming more popular in high volume sectors such as automotive electronics. This is because the urethane resin lends itself to this type of technology more easily than the acrylic based resins.

Want to find out more about polyurethane conformal coating?

What are conformal coating masking boots and why do they save you money?

July 7, 2017 Blog, masking boots

Conformal coating application and masking process at SCH Services facility

Reusable conformal coating masking boots are a highly cost-effective alternative to traditional masking tape.

Many components on printed circuit boards must remain uncoated during the conformal coating process. The purpose of masking is to prevent migration of coating materials into connectors, contacts, and defined keep-out areas where coating would cause functional or reliability issues.

Custom-made masking boots provide a major labour-saving advantage during both the masking and de-masking stages of conformal coating. Unlike tape-based masking, these boots are fully reusable and are simply fitted over components such as connectors, plugs, and sockets prior to coating.

Reusable conformal coating masking boots can be designed as simple push-fit caps for standard connectors or as more sophisticated custom geometries for complex or high-density assemblies, as shown in the examples below.

They provide reliable, repeatable protection across all major conformal coating application methods, including:

Batch and selective robotic spraying (reducing the need for complex programming)
Vertical and horizontal dip coating
Vapour deposition processes such as Parylene coating

Reusable masking boots used in conformal coating operations at SCH Services

Three reasons to switch from masking tape to reusable masking boots

Switching from tape-based masking to reusable masking boots can reduce total masking costs by up to 80%:

Faster application – masking boots can be applied 4–5× quicker than masking tape.
Faster removal – de-masking boots is significantly quicker and cleaner than removing tape.
Lower defect risk – masking boots are far less prone to leakage, reducing rework compared to tape.

The result is a rapid reduction in labour cost, improved process consistency, and fewer coating-related defects when compared to traditional masking tape methods.

Need expert advice on masking PCBs before conformal coating?

Effective PCB masking is critical to prevent coating ingress into connectors, test points, keep-out zones and mechanical interfaces. Poor masking choices can lead to coating defects, rework, reliability issues and unnecessary cost.

SCH supports customers with practical masking strategies tailored to your assembly, coating chemistry and production volume — from reusable masking boots and tapes to liquid masking systems and process optimisation.

If your assemblies also require preparation before coating, you can learn more about our subcontract PCB cleaning and coating services, or speak directly with our engineers to review your masking and coating requirements.

Contact SCH to discuss your PCB masking and conformal coating needs ›

What are the different methods available for cleaning electronic circuit boards?

June 29, 2017 Blog, conformal coating

SCH Services conformal coating facility and production environment

The topic of cleaning printed circuit board assemblies (PCBAs) effectively before application of conformal coating can be daunting. This is because the process of cleaning circuit boards can be difficult especially with so many variables to consider.

When considering cleaning the circuit you need to assess many factors including:

The board and component compatibility with the cleaning method
The ability of the cleaning method to remove the contamination effectively from the circuit
Any residues the cleaning process may leave behind that may be harmful to the circuit in the long term.
The reasons for cleaning the circuit (e.g. contamination removal, adhesion promotion etc.)?

After considering these factors you can compare with the processes available.

The main methods of cleaning printed circuit boards

The main methods of cleaning used in everyday electronics processing before conformal coating application can include:

Aqueous washing
Semi-aqueous washing
Solvent & chemical washing
Plasma surface cleaning

These processes can be mixed, the method can be varied but the fundamental concepts still apply.

However, whatever method you choose you still have to consider that the key to success in cleaning circuit boards is similar to the success made with conformal coating. You need to match the cleaning process, the cleaning materials and the circuit board together. If you do this then this will give you the best results for cleaning the circuit board assembly.

Want to find out more about cleaning?

The Science Behind Fluoropolymer Nano Coatings for Protecting Electronic Circuit Boards

June 22, 2017 Blog, Fluoropolymer

Nano-coatings are being used regularly to protect printed circuit board assemblies. This is because the material they are made of fluorinated polymers and these materials have very specialized properties that produce very different results to traditional conformal coatings.

So, what are the unique properties of a Nano-coating?

To understand the properties of a Nano-coating you have to understand what a fluoropolymer coating is made of.

Typically, the coating itself is comprised of fluorocarbons and characterised by carbon-fluorine bonds. Since the coating is made of fluorocarbons then the film surface is not susceptible to Van der Waals forces (interfacial electrostatic bonds). Therefore, the surface energy of the fluoropolymer coating is extremely low and hydrophobic (water repellent). It acts like Teflon on a frying pan.

This non-wetting of water on the circuit board is one of the many key properties making them so popular.

SCH UK1

What other properties do Nano-coatings have that may help protect circuit boards?

For electronic circuit board assemblies there are several key properties that are being used.

These include being:

Hydrophobic: Being highly water repellent
Ultra-thin: Protection whilst being extremely thin
High moisture barrier: Low water vapor transmission rate provides excellent corrosion resistance
Chemically resistant: Having a high chemical resistance helps protect the circuits from chemical attack.
Good dielectrics: fluoropolymer coatings have high dielectric properties

However, to really understand the benefits you have to look at the key difference compared to a conventional conformal coating. That is that no masking is required when applying the Nano-coating.

So, why is there no need to mask when using a Nano-coating?

First, consider a normal conformal coating is applied at typical thicknesses of 25um or more. Also, the conformal coating is a high insulation material. Therefore, at this thickness the conformal coating would electrically insulate components like connectors and it must not be applied to any part that needs electrical conductivity.

However, this is not a problem for a Nano-coating.

Since the Nano-coating can be applied at ultra-thin thicknesses (1-2um in thickness or less) without any protection performance reduction, then the extremely soft coating is easily removed or scratched away when the connectors are joined and the electrical circuit is easily made.

This key parameter of not requiring masking during Nano-coating application combined with the hydrophobic nature of the coating material makes the Nano-coatings highly effective in protecting electronic circuit boards at a very low cost per unit.

Want to find out more about Nano-coatings?

At SCH Technologies, we supply ultra-thin Nano-coatings based on advanced fluoropolymer chemistries. These coatings provide a cost-effective way to protect printed circuit board assemblies (PCBAs) and other electronics from moisture, corrosion, and environmental damage. We also offer a subcontract conformal coating service and can apply these nano-coatings for you.

Find out more and Contact us now to discuss your needs and let us explain how we can help you.

Five key facts about Parylene when protecting printed circuit board assemblies

June 20, 2017 alternative, Blog, Parylene

Large industrial Parylene coating equipment featuring KR1200HS and KR1500HSU systems for high-volume medical, aerospace and electronics manufacturing

Here are five key facts about Parylene that are critical in understanding this process:

The Parylene conformal coating process is a very specialised vapour deposition application method using specialist vacuum chamber systems. This differs significantly to all of the other liquid conformal coatings available on the market that are applied by spraying, brushing and dipping.
Parylene coating is completely conformal and uniform to the surface of the Printed Circuit Board (PCB) or product. It is also pinhole free. Therefore, components with sharp edges, points, flat surfaces, crevices or exposed internal surfaces are coated uniformly without voids.
Parylene coating provides an excellent moisture and gas barrier due its very low permeability. This means that electronics circuit boards coated in Parylene generally are more “waterproof” than the same electronics coated in a liquid conformal coating.
Parylene is unaffected by solvents (it has very high chemical resistance) and is very effective against salt attack.
Parylene has excellent electrical properties. This includes having low dielectric constant and loss with good high-frequency properties, good dielectric strength, and high bulk and surface resistance.

Find more in-depth details about Parylene materials, deposition principles, masking methods, thickness measurement and core application concepts at our Parylene Basics Hub now.

Or, if you’re interested in moving towards a Parylene process click through to our Parylene Solutions, Parylene equipment and Parylene subcontract services pages.

Want to find out more about Parylene?

Five key facts about using fluoropolymer Nano-coatings for protecting printed circuit boards

June 15, 2017 Blog, Fluoropolymer

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A Nano-coating is hydrophobic. It repels water from the surface of the circuit board and water will not wet the circuit.
The Nano-coatings are extremely thin (<2um). They are very different to traditional conformal coatings.
Nano-coatings do not require masking. The circuit board can be completely submerged in the liquid with no masking applied without damaging components.
They have excellent chemical resistance due its fluorine bonds. The Nano-coatings are perfect to protect against chemical attack.
Using a Nano-coating is a fast simple process. The coating can be dipped quickly, without masking, and the coating dries extremely fast.

Want to find out more about Nano-coatings?

Contact us to discuss your needs and let us explain how we can help you. Or, read more on Nano-coating technology for protecting circuit boards now.

Find out how we can help you with your conformal coating process now.

Three key reasons to use a Molecular Vapor Deposition (MVD) process to protect a circuit board instead of conformal coatings

June 13, 2017 Blog, Molecular vapour deposition

Molecular Vapour Deposition (MVD) is a new process introduced to the electronics coating market. It is a hybrid coating technique using ALD (Atomic Layer Deposition) and CVD (Chemical Vapor Deposition) coating processes in combination.

The method uses multiple layers of ultra-thin coatings with differing properties to build a completely protective coating with a final hydrophobic Nano coating as a top layer.

Here are three key points that strongly suggest you should find out more about this coating:

The physical and electric performance of the MVD coating is superior to other materials like conformal coatings and Parylene. Parameters such as Water Vapor Transmission Rate (WVTR), hydrophobicity, coating adhesion, dielectric strength and temperature performance (>250°C) are vastly improved when protecting circuit boards.
The MVD coating does not require masking to protect sensitive components and electric connectivity in connectors is easily made even when coated. This is because the coating thickness of the MVD material is x10 less than that of Parylene.
The cost of process is much lower than all other protective materials due to the fact that raw ingredients are low cost and no masking is required.

There are many other performance criteria that make this material a really interesting process that could change perceptions.

Want to find out more about Molecular Vapor Deposition?

Contact us now to discuss your needs and let us explain how we can help you. Find out how we can help you with your conformal coating process now.

Nexus article on, “Outsourcing your conformal coating project – The key points”

June 8, 2017 Blog, conformal coating

Outsourcing your conformal coating project - The key points on subcontracting to an external company

Nexus, the independent conformal coating resource, recently published an article on subcontracting your conformal coating services out to a third party.

I thought it would be useful to signpost people to this article and republish the points they raised since getting it right can be so critical in outsourcing. Nexus identified that there are, “three key points to consider when choosing a subcontractor“.

These three key areas were:

Quality
Turnaround time
Price

They stated that,

“if you get these three key areas correct then you have succeeded. Everyone will be happy and there are no more problems with conformal coating.”

(Source: Nexus).

However, within each of these areas, they outlined a lot of questions that should be asked to ensure you get it right. Those points were examined in detail with some real insight into subcontract services.

Want to find out more about subcontract conformal coating services?

Find out how we can help you with your conformal coating process now. Contact us now to discuss your needs and let us explain how we can help you.