Encapsulating components on a circuit board is a balance. The coating has to seal against moisture and mechanical stress, but it cannot distort fine-pitch parts as it cures, and inspectors still need to confirm it went where it should. Incure Uni-Seal 3718F is formulated around those three constraints.

What a Precision Encapsulant Has to Do

Seal without stress. A board-level encapsulant sits directly on solder joints, wire bonds, and small passive components. If the material shrinks hard as it cures, it drags on those features. Over thermal cycling that residual stress becomes cracked joints and lifted pads. A low-stress, low-shrinkage formulation keeps the mechanical load on delicate features small.

Cure fast, in line. Board assembly runs at a cadence. An encapsulant that needs an hour to gel forces work-in-process to pile up. UV cure in seconds keeps the encapsulation step in step with the rest of the line.

Be inspectable. After application, quality control has to verify coverage: did the material reach every component that needed it, and did it stay off the ones that had to remain clear? A fluorescing additive makes that a fast visual check under blacklight instead of a slow manual trace.

Incure Uni-Seal 3718F Properties

• Fast cure in seconds under UV or visible light, with an optional secondary heat cure for regions the light cannot fully reach, such as under a tall component or in a deep pocket.
• Low stress and low shrinkage, minimizing distortion of fine-pitch parts and the substrate during cure.
• Superior moisture barrier, protecting sensitive components from humidity-driven corrosion and dendrite growth.
• Fluorescing feature for rapid coverage inspection and quality control under blacklight.
• Good moisture and temperature resistance for the board’s service life.
• 100 percent solids, no VOCs, so there is no solvent-loss shrinkage and no solvent handling requirement.
• Thermal cycling ready, suited to products that see repeated temperature swings.

For a recommendation on application method and cure setup for a specific board, Email Us with the board layout and the components to be encapsulated.

Applying It

• Board cleanliness. Remove flux residue and handling oils first. Contamination reduces adhesion and can let moisture track under the cured film.
• Dispense control. Use a programmable dispenser for repeatable bead volume and position. Selective application keeps the material on target components and off connectors and test points.
• Bond-line and fillet. A controlled film thickness cures more predictably than a thick, uneven pool. Where a fillet is needed around a component base, size it so light can still reach the fillet toe.

Curing

Cure under a UV LED flood lamp for bench and low-volume work, or run boards through a conveyor curing system at production rate. Verify the delivered dose at the board with a radiometer against the data sheet. Where a tall component shadows encapsulant at its base, follow the UV exposure with the optional heat cure to complete the shadowed region. Confirm full cure by hardness or solvent-rub check on a trial board.

Inspection

Under blacklight, the fluorescing encapsulant shows a clear outline of exactly where material was applied. Confirm every target component is covered and every keep-out area is clean. This check catches dispense misses, clogs, and program errors in seconds, before the board moves on.

Validation

• Thermal cycling across the full service range, then inspection of solder joints and pads for cracking, and of the film for delamination. Account for expansion mismatch between the encapsulant, the laminate, and component bodies.
• Humidity testing with an insulation-resistance measurement to confirm the moisture barrier.
• Adhesion check after aging.

Why Low Cure Stress Protects Fine-Pitch Parts

A fine-pitch package sits on an array of small solder joints, each a few tenths of a millimeter across. When an encapsulant shrinks hard as it cures, it grips the package body and its leads and transfers that contraction into those joints as a static preload. Add thermal cycling on top, and the preload plus the cyclic strain drives solder fatigue cracks that show up as intermittent opens months into service. A low-stress, low-shrinkage encapsulant keeps the static preload small, so the joints start their service life with more fatigue margin. This is why cure shrinkage is a reliability parameter for board-level encapsulation, not just a cosmetic one.

Where It Fits

Uni-Seal 3718F suits board-level encapsulation in automotive electronics, industrial control systems, instrumentation, and other applications where fine-pitch parts, fast line cure, and inspectability all matter. For deeper full-module potting, a dedicated potting grade is the better choice; the tradeoffs are covered in UV glue versus epoxy for encapsulation.

Summary

Uni-Seal 3718F encapsulates precision electronics with low cure stress, seconds-fast UV cure plus an optional heat step for shadowed areas, and a fluorescing aid for coverage inspection. Apply it selectively on a clean board, cure to a verified dose, inspect under blacklight, and validate with thermal cycling. Incure supports board-level encapsulation end to end.

Contact Our Team to discuss a precision encapsulation application.

Visit www.incurelab.com for more information.