Frequently Asked Questions (FAQs)

A thin polymer film (typically 10–100 µm) applied to PCBs to protect against moisture, dust, corrosion, and electrical leakage.

Useful next reads:
Processes Hub
How to select a coating material
Set up a coating production line

It improves reliability, prevents corrosion, and extends product life in harsh operating environments.

Explore typical use-cases:
Industries
Talk to SCH

Conformal coatings are widely used across aerospace, automotive, defence, energy, medical, and industrial electronics where long-term reliability is critical.

More detail:
Industries using conformal coatings

Conformal coating is thin, lightweight and often reworkable; potting is a thick resin encapsulation used for extreme mechanical/environmental protection.

If you’re deciding which route to take:
Discuss your application

Common standards include IPC-A-610 and IPC-CC-830, IEC 60664, relevant MIL specifications, and customer-specific requirements.

Links:
IPC
Conformal coating standards hub
Training courses

A rating (PD1–PD4) describing the level of environmental contamination that influences insulation design choices and, in many cases, the need for coating.

Related industry context:
Industrial electronics applications

Liquid conformal coatings are commonly applied around 25–75 µm, while Parylene is often 5–25 µm depending on the application and specification. Verification is typically done using coated coupons or approved measurement methods.

Practical guidance and measurement options:
Thickness targets
Thickness measurement methods
Thickness measurement equipment

Coatings generally increase surface insulation resistance and reduce leakage. Any added capacitance is usually negligible at typical thicknesses, but sensitive RF/high-impedance designs should be reviewed case-by-case.

If you want a quick design sanity-check:
Contact SCH

Yes. Flux and ionic residues can cause poor adhesion, de-wetting, and long-term reliability failures.

Options and background:
Subcontract cleaning services
De-wetting defect guide

Possibly, but many specifications still mandate additional cleaning. “No-clean” residues can vary and may still impair adhesion and long-term reliability.

Links:
Coating over no-clean (training)
Surface preparation & cleanliness

You can sometimes coat over no-clean assemblies, but the controls must be tighter. If residues aren’t consistent and validated, you can see defects, poor adhesion, and reduced service life.

Next steps:
Discuss your no-clean process
Defects Hub

Align to IPC cleanliness expectations (for example ionic contamination limits) and verify using appropriate tests such as ROSE or ion chromatography depending on the requirement.

Learn more:
IPC cleanliness training
Cleanliness measurement tests

Aqueous spray-in-air, vapour degreasing, ultrasonic, and plasma cleaning are common options—chosen based on contaminant type, assembly design, and reliability targets.

Training route:
Cleaning training modules

ROSE testing, ion chromatography, and SIR testing are used to quantify ionic residues and confirm reliability performance depending on the standard/customer requirement.

Learn how to apply these tests:
Reliability testing training

Yes—pre-coating cleaning and ionic testing can be provided as a standalone service or integrated into a full coating service.

Service info:
Subcontract cleaning & coating

It adds time and process cost, but it typically reduces rework and field failure risk—often lowering total cost of ownership.

If you want help balancing cost vs risk:
Subcontract service options
Request advice

The main methods are spraying, dipping, brushing, robotic selective coating, and vapour deposition (Parylene).

Equipment and deeper reading:
Conformal coating equipment
Parylene equipment
Application processes (article)
Processes Hub

Spraying can suit complex geometries and targeted coverage; dipping gives fast, uniform coverage for higher volume. Masking approach and risk of leakage can differ significantly for each.

Masking guidance:
Masking options
Masking strategies

Vapour deposition (for Parylene) is a vacuum CVD process that deposits a polymer film by gas-phase polymerisation, coating all exposed surfaces with highly uniform coverage.

Learn more:
Parylene solutions
Parylene vs liquid coatings

Cure mechanisms depend on chemistry: solvent evaporation (air-dry), heat cure, UV cure, or moisture-activated cross-linking are common.

Drying/curing equipment:
Drying & curing cabinets

Surface residues reduce surface energy and can trigger defects such as de-wetting or poor adhesion, leading to failures in service.

Guidance:
Surface preparation & cleanliness

Viscosity is typically monitored with Zahn/Ford cups or controlled using inline sensors to keep application parameters stable and repeatable.

Learn and apply:
Viscosity training
Why viscosity matters

UV inspection and magnification are commonly used for coverage validation and root cause analysis; AOI and cross-sections may be used where required.

Inspection options:
UV inspection booths
UV inspection: coverage & edge definition

Yes—selective robotic coating can improve consistency, reduce labour content, and control deposits precisely around keep-out zones.

Best-practice:
Selective robotic coating best practice

Common challenges include bubbles, bridging, shadowing, and uneven thickness—often improved by optimising setup, viscosity control, masking strategy, and flash-off times.

Troubleshooting support:
Troubleshooting training
Defects Hub

A vacuum-deposited polymer that forms a uniform, pinhole-free, conformal film with excellent barrier and dielectric properties.

Commercial overview:
Parylene coating solutions

By chemical vapour deposition (CVD) under vacuum, where monomer polymerises directly on the surface of the part, producing highly uniform coverage.

Equipment:
Parylene machines

For electronics, typical thickness is often 5–25 µm, but medical and aerospace applications may specify tighter windows depending on the requirement.

Thickness measurement:
Parylene thickness measurement equipment

Parylene offers superior 3D coverage and barrier performance, but usually comes with higher cost, longer cycle times, and specialised equipment compared with liquid coatings.

If you want help selecting the best option:
Speak to SCH

Common grades include Parylene N, C, and F (plus HT variants), chosen for trade-offs between dielectric properties, moisture barrier, chemical resistance, and temperature performance.

Compare grades and source materials:
Dimer comparison article
Parylene dimers available

Yes—laser, plasma, or micro-abrasion processes can be used for localised removal to enable access, modification, or repair.

Removal options:
ProBlast Microblast (equipment)
Parylene removal: micro-abrasion (article)

Certain grades are used widely on medical devices and sensors and can meet biocompatibility requirements when specified, processed, and validated correctly.

If you’re working on a medical device, get guidance:
Parylene solutions
Discuss your requirement

Typical limitations include higher cost, longer cycle times, more complex masking requirements, and the need for dedicated vacuum deposition equipment.

Commercial overview:
Parylene coating solutions

Dimer consumption, masking effort, loading density, and vacuum cycle time are the biggest contributors to overall cost per part.

If you want a costed review:
Request a quotation / consultation

Masking protects keep-out zones (connectors, test points, mating faces) so functional interfaces remain coating-free and reliable.

Explore masking solutions and strategy:
Masking materials
PCB masking strategies

Silicone boots, tapes, dots, gels, liquid masks and custom shapes are used depending on geometry, process method, and required edge definition.

Links:
Masking materials (products)
Masking methods & materials (article)

Often yes—provided they are inspected for wear, swelling, or residue so sealing integrity and repeatability are maintained.

Links:
Reusable masking boots
How to mask with a custom boot

Parylene masking must be vapour-tight (to prevent monomer ingress) whereas liquid coatings rely more on surface barriers and adhesive compatibility. The failure modes are different, so the strategy must match the process.

Links:
Masking boots for Parylene
Masking for Parylene (article)

Typical issues include leakage under tape, adhesive residue, inconsistent edges, and variable coverage—usually improved with better fixtures, right-fit boots/shapes, and tighter process controls.

Links:
Masking materials
Design with masking in mind

Use pre-formed boots/shapes, optimise takt time, and train operators on efficient removal techniques to reduce labour and improve consistency.

Links:

Request masking boot samples
Reduce costs with custom shapes

Common defects include bubbles, de-wetting, orange peel, bridging, cracking and delamination—each with specific root causes linked to cleanliness, application parameters, and cure control.

Troubleshooting and learning:
Troubleshooting training
Defects Hub

De-wetting is usually caused by low surface energy or contamination (for example residues, silicones, oils), preventing the coating from wetting and flowing into a continuous film.

Learn more:
De-wetting guide
Defects Hub

Orange peel is a textured surface finish typically caused by imbalance in viscosity, atomisation, flash-off time, or spray setup—often solved by tuning process parameters and environmental control.

Guide:
Orange peel: causes & prevention
Defects Hub

Bubbles can be caused by entrapped solvents or moisture, poor application technique, excessive film build, or insufficient flash-off—often improved by adjusting process parameters and environmental controls.

Support:
Training to prevent bubbles
Bubble solutions (article)
Defects Hub

Delamination is loss of adhesion between the coating and substrate, commonly caused by contamination, incompatible primers/materials, poor cure, or mechanical/thermal stress.

Guide:
Prevent delamination
Defects Hub

Thickness is verified using coupons or approved test areas, measured with optical methods or calibrated gauges depending on chemistry and specification requirements.

Methods and tools:
How to measure thickness
Thickness measurement equipment

Cross-hatch tape testing, pull-off methods, and surface energy checks are commonly used to validate adhesion and wetting performance.

If you want a process review:
Training
Contact SCH

UV inspection (where applicable), magnification/AOI, and occasional destructive cross-sections are used to verify coverage, edge definition, and detect defects.

Equipment:
Inspection booths

Typical chemistries include acrylics, polyurethanes, silicones, epoxies, UV-curables and Parylene—selected based on environment, reliability target, and rework needs.

Selection support:
How to select a coating material
Conformal coating solutions

Match the hazards (temperature, chemicals, condensate, mechanical stress) and serviceability requirements, then validate on coupons/representative parts if there’s any uncertainty.

Guide:
Select a conformal coating material

Adhesion promoters (often primers such as silanes) improve bonding by increasing surface energy and chemical compatibility—especially important for Parylene and low-energy substrates.

Source materials:
Primers & adhesion promoters

Nano coatings are ultra-thin hydrophobic/oleophobic layers that help with splash resistance and ease-of-clean, but they’re not generally a full replacement for conformal coating protection in harsh environments.

Product range:
Fluoropolymer nano coatings

Many modern coatings are RoHS/REACH compliant, but you should always verify supplier declarations and SDS documentation for the exact product and region.

If you want help validating a specific material:
Contact SCH

Some coatings can outgas—material selection and validation testing are particularly important for aerospace/space applications and sensitive optical/electrical environments.

Aerospace context:
Aerospace & defence
Discuss your requirement

Yes—chemical stripping, laser, plasma, or micro-abrasion can be used depending on the coating chemistry, board tolerance, and required precision.

Services, equipment, and methods:
Removal services
Removal equipment
Removal methods (wet & micro-abrasion)

Removal options include chemical strippers, abrasion/micro-blasting, plasma, and laser ablation—each suited to different coatings and levels of precision.

Services, equipment, and methods:
Removal services
Removal equipment
Removal methods guide

Not reliably. You should locally remove the coating before soldering to ensure a clean metallurgical bond. Typical approaches include wet stripping (e.g., WS100 processes) or controlled micro-abrasion (e.g., ProBlast).

Removal routes:
Removal services
Removal equipment
Removal methods guide

Parylene is commonly removed using plasma, laser, micro-abrasion, or targeted chemistries—selected based on area size, precision needs, and substrate sensitivity.

Options:

ProBlast Microblast System
Parylene removal services

Localised defects are often best handled with targeted rework; widespread issues typically require strip and recoat to restore consistent protection across the assembly.

Useful links:
Removal equipment
Defects Hub

Typical platforms include wet stripping systems (e.g., WS100), micro-abrasion blasters, and laser workstations—chosen based on precision and substrate tolerance.

Product range:
Conformal coating removal equipment

With correct methods and controls, removal can be done safely. Incorrect chemistry, abrasive settings, or technique can damage solder mask, lift pads, or compromise components.

If you’re unsure which method is safe for your assembly:
Ask SCH

Common equipment includes dip tanks, spray booths, selective robots, Parylene systems, and drying/curing cabinets—selected based on volume, geometry, and quality requirements.

Equipment ranges:
Conformal coating equipment
Parylene equipment

Yes—SCH can integrate equipment, process setup, masking, consumables, and operator training into a complete turnkey solution.

Overviews:
Conformal coating solutions
Parylene solutions

Yes—masking boots/tapes/dots, adhesion promoters, Parylene dimers and other consumables can be supplied to support both in-house and subcontract production.

Ranges:
Masking
Parylene consumables

Yes—from fundamentals through to advanced troubleshooting, delivered onsite or online depending on need.

Training options:
Parylene training
Conformal coating training

Support typically includes installation, validation, spare parts, and ongoing technical consultancy to maintain yield, quality, and uptime.

Support routes:
Training
Consultation