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Cracked Conformal Coating After Thermal Cycling — A Process Reality Check

Technical Insights

Cracking of conformal coating is most often discovered not during initial inspection, but after thermal cycling, environmental testing, or extended service exposure.

In field investigations, cracking is rarely caused by a single factor. Instead, it is usually the result of combined stresses, such as excessive coating thickness, rigid material selection, and differential thermal expansion between the coating and substrate.

We commonly see cracking:

  • Over sharp component edges or solder fillets
  • Where coating thickness exceeds recommended limits
  • On assemblies exposed to wide thermal excursions

Importantly, coatings that appear compliant and defect-free at room temperature may still fail under thermal stress if thickness and material flexibility are not properly controlled.

A deeper technical breakdown of cracking mechanisms and prevention is available in our Defects Hub article on cracking in conformal coating.

De-Wetting Seen After Cleaning — When “Clean” Isn’t Clean Enough

Technical Insights

A common inspection finding is localised de-wetting of conformal coating, particularly on solder joints or around component leads, even when a cleaning process has been applied beforehand.

In many cases, the boards are genuinely clean in a visual sense. However, de-wetting is often caused by residues that are invisible to the naked eye — including low-level ionic contamination, surfactant residues from aqueous cleaning, or incompatible cleaning chemistries.

Typical characteristics include:

  • Circular pull-back around solder joints
  • Patchy coating coverage on ENIG or HASL finishes
  • Repeatable locations across multiple assemblies

Crucially, operators may notice the effect during coating but assume it is cosmetic. In reality, de-wetting is a strong indicator of a surface energy problem and should always trigger escalation and investigation rather than acceptance.

Detailed causes, acceptance criteria, and corrective actions are covered in our Defects Hub guidance on de-wetting in conformal coating.

Why Conformal Coating Wicks Along Wire Strands — A Field Observation

Technical Insights

During inspection of coated assemblies, we occasionally observe conformal coating creeping along exposed wire strands well beyond the intended coated area. This is often flagged as “over-application”, but in practice the root cause is usually more subtle.

In this scenario, the coating is not flowing excessively during application. Instead, capillary forces draw low-viscosity material along fine wire strands, braid structures, or conductor interfaces after deposition. This effect is amplified where flux residues, incomplete cleaning, or high surface energy materials are present.

We most often see this behaviour:

  • At wire terminations and soldered pigtails
  • Where insulation stripping exposes fine conductor bundles
  • When low-viscosity acrylics or urethanes are used without sufficient flash-off

From a process perspective, this is not something that can be “sprayed out”. Masking strategy, cleanliness, and controlled flash times are far more influential than spray parameters alone.

For definitive technical guidance on this phenomenon, see our Defects Hub page on capillary wicking in conformal coating.

Masking-related defects causing coating ingress and poor boundaries on PCB assemblies

Why Masking Is the Leading Cause of Conformal Coating Defects

Masking

When conformal coating defects appear in production, the first response is often to adjust coating parameters such as viscosity, spray settings, cure profiles, or even material selection. In practice, many coating defects are introduced before coating begins.

Across aerospace, automotive, industrial, and electronics manufacturing, a significant proportion of NCRs and customer rejections trace back to masking decisions rather than coating chemistry. These failures typically occur at boundaries such as connectors, test points, interfaces, and defined keep-out zones.

Masking Defines Where Coating Is Allowed — and Where It Must Not Go

Masking is not a secondary preparation step. It is a primary process control that physically defines the limits of coating coverage. When masking is poorly selected, incorrectly applied, inadequately sealed, or inconsistently removed, defects will occur even when the coating process itself is stable and well controlled.

  • Coating ingress into keep-out zones
  • Coating lifted or removed during de-masking
  • Residue or contamination transferred from masking materials
  • Incomplete touch-up after mask removal
  • Ragged or inconsistent coating boundaries

Why Conformal Coating Masking Defects Are So Often Missed

Masking defects are frequently overlooked because they do not always present as obvious failures during application. The coating may appear uniform immediately after spraying or dipping, with problems only emerging later during inspection, electrical testing, or customer use.

  • No defined inspection step after de-masking
  • Assumptions that shields act as sealed barriers
  • Lack of clarity on operator touch-up versus escalation
  • Over-reliance on UV inspection alone
  • Ambiguous or poorly defined keep-out zones on drawings

Treat Masking as a Defect-Prevention System

Reducing conformal coating defects requires treating masking as a controlled system, not simply a consumable or materials choice.

  • Matching masking methods to function, such as shields versus sealed barriers
  • Controlling fit, placement, and sealing of tapes, boots, and custom shapes
  • Defining de-masking timing and removal techniques
  • Mandating post de-masking inspection
  • Applying clear rules for operator touch-up versus escalation

New Resource: Masking as a Root Cause of Coating Defects

A new root-cause article has been added to the Conformal Coating Defects Hub. It explains in detail why masking is the leading contributor to coating failures and how to control masking effectively in production.

To understand how masking contributes to coating failures in real production environments, read the full masking root-cause analysis.

If you are reviewing masking methods or addressing recurring coating NCRs, explore our conformal coating masking solutions.

Final Thought

If your coating process is stable but defects persist, the fastest improvement often comes not from changing the coating material or parameters, but from reviewing how and where masking is applied, removed, and verified.

Masking does not simply prepare a board for coating. It determines whether the coating process will succeed.

For support reviewing masking processes, inspection criteria, or escalation rules, contact our technical team.

Conformal coating consultancy services covering troubleshooting, process optimisation, benchmarking, NPI support and ongoing technical support

Conformal Coating Consultancy & Process Support

Uncategorized

Troubleshooting, Process Optimisation & Benchmarking

SCH Services Ltd delivers expert conformal coating consultancy across liquid, nano, and Parylene coating processes. We support manufacturers at every stage — from material selection and new product introduction (NPI) through to troubleshooting, process optimisation, and formal benchmarking.

With over 25 years of hands-on industry experience, our consultancy is grounded in real production environments across aerospace, automotive, medical, defence, and industrial electronics. Clients rely on SCH to improve coating reliability, increase yield, strengthen compliance, and resolve complex coating challenges quickly and decisively.

For wider support including equipment, services, and training, explore our Conformal Coating Solutions and Inspection Training resources.

Our Conformal Coating Consultancy Services

Troubleshooting & Defect Resolution

We provide rapid, structured support for coating defects including adhesion failure, bubbles, contamination, de-wetting, and cure-related issues. Our troubleshooting approach aligns with IPC-A-610, IPC-CC-830, and ISO 9001, ensuring solutions are technically robust and audit-ready.

For common defect mechanisms and corrective actions, visit our Conformal Coating Defects Hub.

Process Optimisation

Our optimisation services focus on improving yield, repeatability, and throughput. This includes process tuning, equipment calibration, material compatibility checks, and verification of application and cure parameters.

If you are installing, upgrading, or validating equipment, view our Support Equipment solutions.

Benchmarking & Compliance Review

We benchmark coating processes against IPC standards, ISO 9001, and recognised global best practices to identify risk, variation, and improvement opportunities.

Benchmarking programmes can be paired with Inspection Training to ensure consistent interpretation, inspection discipline, and long-term process control.

New Product Introduction (NPI)

We support the seamless integration of conformal coating into new product launches, covering coating selection, process qualification, documentation, and inspection strategy. Our consultancy ensures coating requirements are correctly embedded from day one.

For end-to-end implementation, see Conformal Coating Solutions.

Ongoing Support Packages

  • Remote or onsite troubleshooting support
  • Regular process optimisation and audits
  • Compliance validation and technical documentation
  • Expert guidance on new materials, equipment, and coating technologies

Where outsourcing is preferred, explore our Subcontract Coating Services.

Why Choose SCH Services?

Partnering with SCH Services gives you access to a fully integrated platform covering Conformal Coating, Parylene, and ProShieldESD solutions, supported by equipment, materials, and training — all delivered by engineers with decades of real-world coating experience.

  • ✈️ 25+ Years of Expertise – Trusted specialists across aerospace, medical, defence, automotive, and electronics manufacturing.
  • 🛠️ End-to-End Capability – From coating selection and masking strategy to inspection, rework, and ESD-safe solutions.
  • 📈 Scalable Support – Consultancy and capacity that adapts from prototypes through to high-volume production.
  • 🌍 Global Reach – Technical support and supply coverage across Europe, North America, and Asia.
  • ✅ Proven Reliability – A reputation built on quality, consistency, and long-term customer trust.

📞 Call: +44 (0)1226 249019  | ✉ Email: sales@schservices.com  |  💬 Contact Us ›

Why do so many conformal coating problems appear “random”?

conformal coating

Why Conformal Coating Problems Often Appear Random — And Why They Aren’t

In most cases, they aren’t random at all — they are symptoms of a process that was never aligned from the start. Conformal coating only works reliably when PCB design, environmental demands, coating chemistry, application method and inspection strategy all work together as a unified system.

To help manufacturers establish stable, scalable and predictable coating processes, we’ve published a fully updated guide:

👉 Holistic Conformal Coating Process – End-to-End Framework

Below is a high-level summary. For the full technical model, diagrams and linked resources, explore the article above.

1. It all begins with PCB design

Most coating challenges originate at the design stage — long before production starts. Poor keep-outs, difficult orientations, insufficient drain paths or incompatible materials lead to:

  • excessive masking
  • rework and inspection delays
  • pooling, edge thinning and trapped solvent
  • long-term reliability risks

A design that supports coating reduces cost and improves first-pass yield.

Explore the Design for Conformal Coating Hub:

👉 Design Hub Articles

2. Chemistry must be matched to the real environment

No coating is universally suitable. Chemistry selection should be driven by environmental stress, including:

  • humidity and condensation
  • SO₂ / H₂S corrosion
  • fuels, oils, chemicals and solvents
  • UV exposure
  • thermal cycling and vibration
  • high-voltage creepage and clearance

Using the wrong chemistry often results in de-wetting, cracking, poor adhesion or long-term corrosion.

Explore:

👉 Parylene Coating Solutions

👉 ProShieldESD Conductive Polymer Platform

3. The application method must suit material, volume & geometry

Selective coating, manual spray, dip coating and Parylene each solve different process challenges. Selecting the wrong method leads to inconsistent thickness, material waste and increased labour.

Your method should reflect:

  • production volume
  • assembly density
  • design geometry
  • material selection
  • drainage capability
  • masking burden

See the Coating Process Hub Overview:

👉 Coating Processes Hub

4. Material & process control prevent drift

Even well-designed processes degrade over time if material conditions are not tightly managed.

Small variations in:

  • viscosity
  • solvent balance
  • 2K mix ratio
  • temperature & humidity
  • flash-off or cure profile

…can create large deviations in coverage, edge definition, adhesion and repeatability.

Good material management is one of the strongest predictors of coating stability over time.

5. Inspection closes the loop

Inspection validates the process and ensures defects are caught before assemblies reach customers.

A robust inspection strategy should include:

  • UV contrast and coverage checks
  • thickness measurement (preferably with coupons)
  • adhesion and environmental tests
  • periodic functional/hi-pot checks

Explore the Inspection & Quality Hub:

👉 Inspection & Quality Articles

SCH-manufactured UV Inspection Booths:

👉 UV Inspection Booths

6. Continuous improvement keeps the process stable

Production changes, new PCB variants and supplier shifts all introduce risk. Without structured review, even a previously stable line can begin to drift.

SCH’s consultancy team provides:

  • NPI validation & materials benchmarking
  • full process audits
  • defect pattern analysis
  • SPC review & control planning
  • design alignment and masking strategy optimisation

Explore:

👉 Conformal Coating Consultancy

7. When Parylene is the smarter choice

For certain assemblies, liquid coatings will never deliver the required performance. Parylene excels when:

  • geometries are complex
  • components are closely packed
  • surfaces are hidden, recessed or sharp-edged
  • moisture protection must be absolute
  • very high electrical resistance or stability is required
  • field reliability is mission-critical

Explore:

👉 Parylene Coating Services

👉 Parylene Deposition Systems

8. Why the holistic model matters

Failures rarely originate in the coating booth. They arise from misalignment of design, chemistry, application method or environment.

Symptoms include:

  • dewetting
  • fisheyes and pinholes
  • inconsistent thickness
  • chronic masking leakage
  • pooling and edge thinning
  • delamination and poor adhesion

These issues often appear random — yet almost always stem from upstream decisions.

Explore the full Coating Defects Hub:

👉 Common Coating Defects

9. SCH’s Total Solutions Approach

Whether you coat in-house or outsource, SCH provides full lifecycle support across both liquid coatings and Parylene.

⭐ In-house coating support

⭐ Outsourced coating services

Explore:

👉 Total Conformal Coating Solutions

🔍 Read the full technical framework

This blog provides a high-level summary only. For the complete methodology, diagrams, commercial considerations and cross-linked technical resources, view the full article:

👉 Holistic Conformal Coating Process – Full Guide

Universal ProShieldESD conductive polymer coating tested live at Productronica 2025 across multiple substrates

ProShieldESD – Productronica 2025 Technical Report

ProShieldESD

ProShieldESD – The World’s First Universal, Fully Functional ESD Coating

ProShieldESD is a filler-free conductive polymer ESD coating (often described as an “ESD paint” due to its
ease of application) designed to deliver repeatable, standards-aligned static control across a wide range of substrates.
Unlike traditional ESD coatings that rely on carbon, metal fillers, graphite, or temporary surface additives, ProShieldESD forms a stable resistive network that bonds effectively to rigid, flexible, porous, and smooth materials.

In practical terms, ProShieldESD can convert everyday items into uniform ESD-dissipative surfaces suitable for
electronics manufacturing environments. Typical substrates include tiles, PP flute board, EVA foam, cartons, PVC mats, tools, bins, and even brush handles and bristles—without significantly changing the base material’s mechanical behaviour.

This makes ProShieldESD a single-platform approach for building controlled ESD-safe environments across floors, packaging, handling aids, trays, storage, accessories, and fixtures.
Explore ProShieldESD ↗

Live ESD Testing at Productronica 2025, Munich

To demonstrate real-world performance under professional conditions, ProShieldESD was tested live at Productronica 2025 in Munich using the sparktrap® EPA SafeAssure® (Keinath Electronic GmbH, Germany) — a dedicated ESD multimeter designed for accurate, standards-oriented measurement.

Measurement capability highlights:

  • Flat weight probe for surface resistance
  • Concentric ring probe for surface resistivity
  • Precision 2-point probe for small objects
  • Integrated temperature, humidity & voltage monitoring
  • High-stability 100 V measurement mode
  • IEC 61340 & ANSI/ESD S20.20 conformity

Environmental conditions during testing:

  • Temperature: 22–23 °C
  • Humidity: 53–55% RH
  • Test voltage: 100 V

Measurement Results – sparktrap® EPA SafeAssure®

Material Avg Resistance Scientific Notation Assessment Technical Note
Flooring (Tile + ProShieldESD) 1.501 MΩ 1.5 × 10⁶ Ω Excellent Within a strong ESD floor range for controlled discharge.
PP Flute Board 4.778 MΩ 4.8 × 10⁶ Ω Very Good Stable dissipative range suitable for packaging/handling.
Carton Box (Coated) 741.9 MΩ 7.4 × 10⁸ Ω Very Good Higher dissipative value; useful for packaging applications.
EVA Foam 65.35 MΩ 6.5 × 10⁷ Ω Very Good Consistent dissipative behaviour for protective inserts.
PVC Mat 964.3 kΩ 9.6 × 10⁵ Ω Excellent Classic ESD mat range around 10⁶ Ω.
ESD Linbin 1.699 MΩ 1.7 × 10⁶ Ω Very Good Suitable range for ESD-safe component storage.
Plastic Carry Case 1.644 MΩ 1.6 × 10⁶ Ω Excellent Uniform dissipation; good target range for handling aids.
ESD Brush – Handle 3.009 MΩ 3.0 × 10⁶ Ω Excellent Provides a safe discharge path during tool use.
ESD Brush – Bristles 317.0 kΩ 3.1 × 10⁵ Ω Excellent Lower resistance beneficial for contact discharge behaviour.
ESD Pen 2.113 MΩ 2.1 × 10⁶ Ω Excellent Helps prevent charge accumulation during handling.
Metal Surface 88.19 kΩ 8.8 × 10⁴ Ω Conductive Expected conductive reference surface.

Conclusion & Acknowledgement

The Productronica 2025 demonstration highlighted two practical advances for ESD control:

  • ProShieldESD — a universal, filler-free conductive polymer ESD coating that enables repeatable static-control performance across diverse substrates.
  • sparktrap® EPA SafeAssure® — a purpose-built ESD multimeter supporting more consistent, standards-oriented evaluation.

Together, these innovations show how manufacturers can extend ESD control beyond benches and mats—into floors, packaging, tools, storage, and handling systems—using an engineered coating approach.

SCH Coating Solutions thanks Keinath Electronic GmbH for their collaborative support at Productronica 2025 and for
providing the sparktrap® EPA SafeAssure® instrument during the live demonstrations.

Want to discuss your substrates, targets, and validation approach?
Contact SCH →

Why Parylene Dimer Purity Defines Coating Performance

Parylene

Clean chemistry, flawless coatings

Behind every reliable Parylene coating lies the dimer — a crystalline, purified precursor that drives the entire deposition process. Parylene dimer purity is the single most critical factor in achieving flawless polymerisation, electrical performance and long-term reliability.

When sublimed and cleaved under vacuum, the dimer becomes a reactive monomer that polymerises onto every exposed surface, forming a perfectly conformal, pinhole-free film.

But that level of precision depends on one factor above all others: purity.

How impurities affect coating quality

Even trace contamination in a Parylene dimer can have major consequences. Impurities such as moisture, oxygen, halogens, metal residues or unreacted intermediates can:

  • Reduce dielectric strength by interrupting polymer chain growth
  • Cause discolouration or haziness in the deposited film
  • Lead to pinholes, voids, and residues during sublimation and pyrolysis
  • Trigger uneven coating thickness or adhesion issues

Because the Parylene process amplifies any chemical irregularity during polymerisation, even parts-per-million contaminants can result in visible or electrical defects.

Why SCH focuses on ultra-pure feedstock

SCH Services Ltd sources and supplies high-purity Parylene dimers for advanced electronics, aerospace, and medical applications. Each batch undergoes controlled crystallisation, vacuum drying and contamination screening to ensure complete chemical consistency.

Our commitment to purity extends beyond production — it’s independently verified.

Independent SGS verification

Independent SGS testing throughout 2025 confirmed that all SCH Parylene materials — including Parylene N, C, D and fluorinated F (AF-4) — contain no detectable Substances of Very High Concern (SVHCs), polycyclic aromatic hydrocarbons (PAHs), or PFOS/PFOA compounds to ppm-level detection limits.

Fluorinated grades also meet full RoHS 2.0 (2015/863) compliance.

This independent verification demonstrates ultra-high-purity feedstock (>99.9 % equivalent), ensuring stable polymerisation, high dielectric performance, and pinhole-free coatings across the entire SCH Parylene range.

Performance benefits of high-purity Parylene

  • Improved dielectric strength and insulation resistance
  • Cleaner surface finish with no whitening or carbonised residue
  • Consistent film uniformity across complex geometries
  • Reduced risk of adhesion failures and outgassing
  • Enhanced long-term reliability under thermal or chemical stress

Certified materials for demanding industries

Whether you’re coating aerospace PCBs, medical implants, or automotive sensors, the purity of the dimer defines the quality of the final coating.

SCH’s independently tested materials ensure regulatory compliance, consistent film quality and traceable supply.

Frequently Asked Questions: Parylene Dimer Purity

Why does Parylene dimer purity matter?

Parylene dimer purity directly affects polymerisation, dielectric strength, film uniformity and long-term reliability. Even trace contaminants can disrupt chain growth, leading to pinholes, discolouration, adhesion loss or electrical instability.

What impurities cause problems in Parylene coatings?

Common problematic impurities include moisture, oxygen, halogens, metal residues and unreacted intermediates. These can cause voids during sublimation, hazy films, uneven thickness and reduced insulation resistance.

Can low-purity Parylene dimer still meet thickness targets?

Yes — but thickness alone does not guarantee performance. Low-purity dimers may reach nominal thickness while still producing coatings with reduced dielectric strength, pinholes or long-term reliability failures.

How does dimer purity affect dielectric performance?

High-purity Parylene dimers allow uninterrupted polymer chain formation, resulting in higher dielectric strength, stable insulation resistance and improved performance in high-voltage or high-humidity environments.

Are SCH Parylene dimers independently tested?

Yes. SCH Parylene materials have been independently tested by SGS and confirmed to contain no detectable SVHCs, PAHs or PFOS/PFOA to ppm-level detection limits. Fluorinated grades also meet full RoHS 2.0 compliance.

Does higher dimer purity reduce coating defects?

Yes. High-purity feedstock significantly reduces the risk of pinholes, hazing, carbonised residues, adhesion failures and outgassing — especially on complex geometries and sensitive electronics.

Learn more

Explore our full range of Parylene dimers or dive deeper into the chemistry behind coating performance in the Parylene Dimers Hub and find out how dimer purity affects coating quality.

All SCH Parylene materials have been independently tested by SGS to confirm no detectable SVHCs, PAHs or PFOS/PFOA, ensuring the highest levels of purity and performance.

Conformal coating masking methods to prevent coating defects, leakage and rework

Masking Made Easy – 3 Ways to Reduce Defects in Conformal Coating

Masking

Masking is one of the simplest steps in conformal coating — and one of the most common causes of defects, rework and customer complaints when it goes wrong. Coating on connector pins. Adhesive residue left behind. Silicone boots leaking. Latex that tears or pulls the coating away. These issues cost time and money — but most are preventable.

The solution isn’t only better operator training — it starts with using the right masking materials and adhesives, the same paper-based tapes, dots and pre-cut shapes we use in our own coating services every day. To understand all available masking materials, see Conformal Coating Masking: Methods & Materials to review different tapes, dots, custom boots, latex and pre-cut shapes.

Why Masking Goes Wrong

Masking protects connectors, test pads, gold fingers, housings and other areas that must remain coating-free. Most masking failures are caused by:

  • Coating wicking under tape, dots, shapes or silicone boots
  • Coating de-wetting away from the tapes and dots due to the adhesive used.
  • Adhesive residue left behind after removal
  • Using general-purpose tape instead of conformal coating tested materials
  • Silicone boots that don’t seal or are worn out
  • Liquid latex applied too thick or removed too late
  • No inspection during demasking

To better understand leak paths and barrier methods, see Conformal Coating Masking Strategies – Barrier vs Shielding.

1. Choose the Right Masking Method — and the Right Adhesive

Masking Tape

  • Best for: General areas, edges and flat surfaces
  • Benefits: Low cost, flexible, easy to apply
  • Important: Must be paper-based, low-tack, clean-release. Avoid Kapton or painter’s tape — they leave residue or pull coating off.

Masking Dots & Discs

  • Best for: Test pads, vias, screw holes
  • Benefits: Fast, consistent sizing, no cutting needed
  • Important: Use paper-based coating-safe masking discs. Vinyl stickers, labels or strong adhesives will leave residue or lift coating.

Pre-Cut Masking Shapes (Custom Paper Shapes on Sheets/Rolls)

  • Best for: Complex flat areas, precision masking, gold fingers, connector faces, repeat PCB builds
  • Benefits: No hand-cutting, accurate placement, speeds up production
  • Important: Made from specialist paper masking material with low-tack adhesive — same type we use daily in conformal coating services.

Silicone Masking Boots & Caps

Liquid Latex / Hybrid Barrier Systems

  • Best for: Board edges, non-flat surfaces, irregular shapes
  • Benefits: Seamless coating barrier where tape cannot reach
  • Important: Apply in thin coats, peel at the correct time. See Liquid Latex & Hybrid Barrier Systems – sealing tapes & keep-out edges.

🛒 Want materials? Visit Masking Boots, Tapes, Dots & Pre-Cut Shapes from SCH.

2. Apply Masking Correctly — Clean, Seal and Fit

Even the right masking materials fail if they’re not applied properly.

Best Practice:

  • Clean the board before masking — oils and flux stop adhesives sealing.
  • Press tape/dots/shapes firmly, especially around edges.
  • Use Pre-Cut Masking Shapes for speed and consistency in repeat jobs.
  • Fit boots fully — no lifted edges or gaps. For guidance, see How to Mask a PCB with Boots – A How to Guide.
  • Latex must be applied in thin layers and peeled before it fully hardens.

For understanding the benefits of reusable boots in production environments, see Reusable Masking Boots – cost, speed, repeatability.

3. Inspect During Demasking — Not After Testing

Most masking failures are found too late — after coating cures or during electrical test. The best time to detect problems is while removing masking.

During demasking, check for:

  • Coating on pins, connectors or gold fingers
  • Adhesive residue or paper fibres
  • Coating lifting with the tape or shapes
  • Silicone boots pulling coating at the edges
  • Latex tearing or leaving fragments

Early detection = repair before full cure.

More masking advice can be found in Conformal Coating Masking: Methods & Materials –and Designing Effective PCB Masking Strategies.

💡 Bonus Tips — Speed Up Masking, Reduce Rework

  • Use Pre-Cut Masking Shapes for intricate masking, complex areas, gold fingers and flat surfaces in repeat builds.
  • Replace silicone boots when they swell, crack or don’t seal.
  • Use latex or hybrid barrier approaches on difficult edges — see Liquid Latex & Hybrid Barrier Systems – sealing tapes & keep-out edges.
  • Add masking diagrams and photos to work instructions.
  • Train operators specifically in masking and demasking — not just coating.

Conclusion

Most masking problems aren’t caused by operator error — they’re caused by using the wrong tape, dots, shapes or boots.

Using the correct conformal coating masking tapes, dots, custom pre-cut shapes, silicone boots or peelable latex, applied and removed at the right time, will drastically cut defects, rework and costs.

Hands-on Parylene conformal coating training covering deposition, masking and inspection

Training, Trust & Technology – The SCH Way of Working

Training

At SCH Services Ltd, we believe that excellence doesn’t happen by chance. It’s built—carefully, consistently, and collaboratively—through three key pillars: training, trust, and technology.

In the high-precision world of conformal coating, Parylene deposition, and ESD control, every detail matters. But behind every perfect finish is something even more important—a team that’s skilled, trusted, and equipped with the right tools.

Training: Building capability from the inside out

SCH’s success is built on people who understand why their work matters. From new starters to senior technicians, everyone is part of an ongoing development journey that combines structured training with on-the-job experience.

We invest in:

  • Structured training pathways for coating, masking, demasking, inspection, and Parylene application.
  • Competency matrices that track skill progression and highlight where extra coaching is needed.
  • Cross-functional learning, so each person understands not just their own process, but how it connects to the next.

Training isn’t just about compliance—it’s about confidence. When staff understand both the process and the purpose, they take pride in the results.

Trust: Empowering people to deliver

Trust is at the core of how we work. We hire for potential and attitude, then give people the structure and autonomy to succeed.

At SCH, we believe:

  • Trust means delegating responsibility, not just tasks.
  • Accountability grows when people feel ownership of outcomes.
  • Open communication creates a workplace where feedback leads to improvement, not fear.

Our production, quality, and operations teams work hand-in-hand—supported, not micromanaged. That trust shows in the consistency of our output, the reliability of our customer commitments, and the way our staff support one another when pressure is on.

Technology: Precision through innovation

Technology is the third pillar of the SCH way. From advanced selective coating and UV inspection systems to Parylene vacuum deposition and ProShield ESD™ control, our investment in technology keeps us ahead of industry standards.

We use technology to:

  • Reduce variation and improve repeatability.
  • Track efficiency and quality metrics across every job.
  • Shorten turnaround times while maintaining strict process control.

Innovation at SCH isn’t about chasing the latest gadget—it’s about using the right technology to make people’s work easier, safer, and smarter.

Where the three pillars meet

When training, trust, and technology align, you get more than just good results—you get a culture of continuous improvement.

  • Trained people use technology better.
  • Trusted people take ownership of quality.
  • Modern tools free skilled staff to focus on detail and precision.

That’s the SCH difference. It’s why our customers rely on us for high-reliability coating solutions, and why our people stay, grow, and take pride in what they do.

The SCH Way – simple, effective, human

At the end of the day, we’re a people business powered by technology. Whether we’re coating a medical device, protecting an aerospace circuit, or implementing an ESD program, our approach remains the same—train well, trust deeply, and invest wisely.

That’s the SCH way of working.

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Conformal Coating UK

Technical banner showing PCB and process icons representing conformal coating, masking, inspection and training on the SCH technical knowledge hub.
Conformal Coating UK
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