Process FAQs

Dip, spray (manual/automated), robotic selective, and brush for rework. Choice depends on geometry, masking load, throughput, and material.

Dip gives full coverage and high throughput but needs more masking. Spray/selective reduces masking and targets coverage for complex boards.

Board carriers, rotation/tilt jigs, and keep-out shields minimise shadowing and overspray while improving repeatability.

Use witness coupons, UV inspection, cross-sections where needed, and document parameters for repeatability.

Solvent evaporation (ambient or heated), moisture/condensation cure, heat cure, and UV cure (with secondary mechanism for shadows).

Control film build, flash-off time, airflow, and temperature; multiple light coats perform better than one heavy pass.

They’re recommended for solvent-based materials to stabilise conditions and shorten cycle time; follow the TDS cure window.

Check hardness/tack-free status, mass change, FTIR where applicable, and run electrical/insulation or SIR tests as required.

Flux and process residues can cause adhesion failures, leakage, and corrosion under the film; cleaning improves long-term reliability.

Set a spec using ionic contamination, SIR, or ROSE limits appropriate to end-use; verify routinely and after process changes.

Aqueous, semi-aqueous, or solvent cleaning with validated chemistries; ensure full drying before coating.

SIR, humidity/thermal cycling, salt fog, or mixed-flowing gas as required by the product’s environment and standards.

Dewetting, fisheyes, bubbles/voids, orange peel, bridging, and pinholes—typically driven by contamination or parameter drift.

Improve cleanliness and surface energy, filter material, and review silicone/contaminant sources in the work area.

Use chemistry-compatible stripping (for acrylics), mechanical removal, or plasma for Parylene; then clean and recoat per spec.

Tune viscosity and pass strategy; use keep-out dams or selective paths to avoid excess build and sharp menisci at leads.

Wet film combs during application; dry film by eddy-current on metal, gravimetric on coupons, or calibrated optical methods.

Follow the coating TDS and customer spec; typical ranges are ~25–75 μm for liquids and ~10–25 μm for Parylene (varies by type).

Control viscosity, equipment speeds, passes, and cure conditions; validate with coupons and in-process checks.

Use representative flat areas or designated coupons; avoid edges and tall components that distort readings.

It directly affects film build, flow, and defect rates; stable viscosity improves repeatability.

Use calibrated cups (e.g., Zahn, Ford) at a set temperature; record and trend values with add-back rules.

Solvent loss, temperature swings, and shear history; mitigate with lids, controlled makeup solvent, and temperature control.

Pot life limits, batch logs, regular filtration, and defined adjustment steps to keep within the process window.

Under UV and white light for coverage, defects, and workmanship; use magnification as required by the spec.

Typically IPC-A-610 for workmanship and IPC-CC-830 (or IEC/MIL equivalents) for material/qualification requirements.

Material batch, parameters, inspection results, defects/rework, and sign-offs for traceability.

Most programs require full visual inspection; sampling may apply for certain in-process checks if justified.

Surface energy and cleanliness, correct cure, and material compatibility; primers/adhesion promoters where needed.

Cross-hatch (e.g., ISO 2409), peel, or pull tests on coupons/representative areas; define acceptance criteria.

On low-energy surfaces (gold, glass, some plastics) or in harsh environments; e.g., A-174 silane for Parylene.

Improve cleaning, roughen/activate surfaces (plasma), use primers, and confirm cure parameters; then re-validate adhesion.