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…

Potting protects electronics from moisture, vibration, and aggressive fluids by embedding them in a cured resin. The property that most often separates a reliable potting compound from a problem one is cure shrinkage. A resin that pulls in as it cures puts every embedded component under stress and can open a leak path at the pot wall. Why Shrinkage Matters All curing resins shrink to some degree as liquid monomer converts to a solid network. In a potted module that shrinkage acts in three damaging ways: Component stress. The resin grips leads, solder joints, and component bodies and pulls on them as it contracts. Fine wires, ceramic capacitors, and glass diode bodies are sensitive to this. Interface separation. Shrinkage away from the potting-shell wall or a connector face creates a gap that moisture and gas can enter, defeating the seal. Warpage. Uneven shrinkage through a thick pot bends the substrate or the housing. A low-shrinkage resin minimizes all three. UV-curable acrylic potting compounds formulated at 100 percent solids avoid the additional shrinkage that solvent-borne systems suffer as solvent leaves, and they cure fast enough for inline production. Incure Uni-Seal Potting and Sealing Line Incure's Uni-Seal potting grades are designed for encapsulation where dimensional stability and fast cure both matter: Rapid cure, with some grades reaching full cure in about 60 seconds under a UV source, versus hours for a two-part thermoset. Very low shrinkage and very low water absorption, so the cured resin stays dimensionally stable and does not swell in humid service. Protection against mineral oils, gases, and common process chemicals, which suits utility metering, fluid-system electronics, and industrial sensor potting. Good adhesion to many metals and to glass, keeping the resin sealed to the housing and to feed-through pins. Color options, including opaque grades where the potted circuit must be hidden. Where an application references specific standards such as EN 16314 or EN 1359 for gas-metering equipment, confirm the exact grade's documented compliance against the current standard text. For a grade recommendation against your module and its environment, Email Us with the potting geometry and fluid exposure. Design and Process Pot depth and light path. UV cure needs light to reach the resin. A shallow pot cures top-down in one exposure. A deep pot, or one with components that shadow the resin below them, needs either a translucent resin that lets light propagate, a dual-cure grade with a secondary heat step, or staged filling with a cure between lifts. Fill technique. Dispense slowly along the pot wall to avoid entraining air. Vacuum degassing before cure removes trapped bubbles that would otherwise become moisture traps. Bond-line and wall adhesion. Clean the housing interior. Residual mold release or flux lets the resin debond from the wall as it shrinks, however slightly. Curing Cure under a UV LED flood lamp for bench work, or a conveyor system for volume, with a batch cure chamber an option for even exposure of many parts at once. Verify the delivered dose at the resin…

Form-in-place and cure-in-place gasketing replace a cut rubber part with a liquid bead dispensed and cured directly on the component. Done with a UV-curable material, the cure takes seconds instead of hours, which is what makes the method practical for volume production. FIPG and CIPG: The Difference Form-in-place gasket (FIPG): The seal bead is dispensed onto one flange and cured before the mating part is assembled. The result is a fully cured elastomer gasket attached to one half of the joint. The parts then bolt together, compressing the cured gasket like a conventional seal. Cure-in-place gasket (CIPG): Similar dispensing, but the emphasis is on the gasket being a permanent, adhered feature of the part, cured in place as a functional component rather than a consumable. In practice UV FIPG materials serve both roles, since they cure fully and quickly on the flange without needing the second part present. Both approaches share the same advantages over die-cut gaskets: no pre-cut inventory, no scrap skeleton, no seam leak paths, an exact fit to any flange path, and consistent bead volume from an automated dispenser. Why UV Cure Room-temperature-vulcanizing silicone FIPG needs minutes to hours of skin and cure time, tying up the part and limiting line speed. A UV-curable FIPG cures on demand: dispense the bead, pass it under a lamp, and it is a handleable gasket in seconds. That collapses work-in-process and lets the gasket station keep pace with the rest of the line. Incure Uni-Seal 6322 Incure's Uni-Seal 6322 is a UV-curable form-in-place gasket and sealant. It serves as both a gasket and a sealant in one material, and cures very fast under low-energy LED lamps, which suits high-volume production. Its properties for enclosure sealing: Air-tight seal with excellent conformance to the flange surface. High resilience and flexibility, with good elastic memory so the gasket recovers after repeated compression cycles, outperforming many conventional cut gaskets on recovery. Moisture and temperature resistance for demanding service environments. Chemical resistance, which is why the material is widely used in electronics and automotive enclosures exposed to oils and process fluids. 100 percent solids with no solvent, so there is no shrinkage from solvent loss and no VOC handling. For a recommendation on bead size and cure setup for your flange, Email Us with the enclosure drawing and production rate. Designing the Bead Compression target. Size the dispensed bead so it reaches 20 to 40 percent compression at assembly. Too little and the seal is marginal; too much and the gasket fatigues early. Groove or hard stop. A retaining groove positions the bead and limits compression. On a flat flange, design a metal-to-metal hard stop so bolt torque cannot crush the gasket. Flange rigidity. Keep bolt spacing close enough that compression stays even between fasteners. A flexible flange bows outward mid-span and opens the seal. Path tie-in. Program the dispense path to overlap cleanly at the start and end with no thin section. Curing Dispense, then cure under a UV source matched to the flange…

A gasket that seals perfectly on the assembly line and then chalks, cracks, and leaks after a year outdoors has failed at its actual job. For enclosures that live in sunlight, the seal material's resistance to ultraviolet degradation matters as much as its initial compression set. UV-curable formed-in-place gaskets can be formulated to hold up. How UV Degrades a Gasket Ultraviolet energy in sunlight breaks polymer chains at the surface of most elastomers. The visible signs are chalking, surface crazing, loss of elasticity, and eventually through-cracks that open a leak path. Rubber gaskets based on unsaturated backbones, such as many EPDM and nitrile compounds, are vulnerable unless heavily stabilized. Once a gasket loses its elastic recovery, it no longer follows the flange as temperature and pressure cycle it, and the seal is lost. Why a Formed-in-Place UV Gasket Helps A UV-curable formed-in-place gasket is dispensed as a liquid bead directly onto the flange, then cured in seconds under a UV lamp to a resilient elastomer. Compared with a die-cut rubber gasket it removes the inventory of pre-cut parts, eliminates seam and joint leak paths, and lets the seal follow any 2D flange path exactly. Formulated with a saturated acrylic or urethane-acrylate backbone and appropriate stabilizers, the cured gasket resists the chain scission that attacks conventional rubbers, so it keeps its elasticity through prolonged outdoor exposure. Incure Uni-Seal UV Gasket Line Incure's Uni-Seal UV gasket grades are 100 percent solids, cure rapidly under low-energy LED lamps, and cure to a soft, resilient, memory-retaining elastomer. Key properties for outdoor and demanding service: Fast LED cure suited to high-volume production, with no solvent flash-off and no shrinkage from solvent loss. High resilience and elastic memory, so the gasket recovers after each compression cycle and keeps following the flange. Low water absorption and low shrinkage, which supports dimensional stability through thermal cycling. Chemical resistance to oils, fuels, and common process fluids, which is why the chemistry is widely used in electronics and automotive enclosures. Adhesion to metals, glass, plastics, and FR4, so the gasket stays put on the flange rather than migrating. For a grade recommendation against your enclosure material, flange geometry, and exposure conditions, Email Us with the assembly details. Designing the Seal Bead cross-section: Size the dispensed bead so that at the design compression, typically 20 to 40 percent, the gasket fills the groove or contact area without over-compressing. Over-compression accelerates fatigue. Flange stiffness and bolt spacing: The flange has to hold even compression between fasteners. Wide bolt spacing on a thin flange lets the seal gap open mid-span. Groove versus surface bead: A retaining groove controls the gasket position and limits how far it can be compressed. A surface bead is simpler but needs a hard stop designed in. Path continuity: Program the dispense path to close on itself cleanly, with a controlled tie-in at the start and end so there is no thin spot. Curing Dispense, then cure with a UV source sized to the flange. A UV LED flood…

Adhesive bonding has largely replaced screws, rivets, and welds for joining plastic to metal in consumer electronics, automotive trim, appliances, and instrument housings. It spreads load, seals the joint, and avoids the stress concentrations that fasteners create in plastic. The catch is that plastic-to-metal is a dissimilar-material joint, and it has to be engineered as one. The Two Surfaces Metal is high-energy and easy to wet, but its real surface is an oxide layer plus whatever oil, scale, or coating arrived with it. Bond strength tracks how well that layer is cleaned and stabilized. Plastic ranges from easy (polycarbonate, ABS, acrylic) to difficult (acetal, nylon) to very difficult (polyethylene, polypropylene). Surface energy is the tell: above roughly 38 mN/m an adhesive wets well; below it, the adhesive needs help from plasma, corona, or a primer. The Movement Problem The defining feature of a plastic-to-metal joint is thermal expansion mismatch. Metals sit at 12 to 23 ppm per degree C. Plastics commonly run 50 to 100 ppm per C. Every heating and cooling cycle shears the bond line as the plastic grows and shrinks more than the metal. A joint designed only for its static load, with a rigid adhesive, will fatigue at the edges. Designing for the movement, with a compliant adhesive and adequate bond area, is what makes the joint last. See how CTE mismatch causes adhesive bond failure. Adhesive Families UV and visible-light-curable acrylates. Cure in seconds when light reaches the joint, ideal for high-volume lines and for bonding through a UV-transmitting plastic. Grades span rigid to highly elastic, so a compliant grade can be chosen for the thermal mismatch. Clear cure suits visible joints. Two-part epoxies. High rigidity, high chemical resistance, cure in shadow, fill gaps. Long fixture times and limited movement tolerance make them better for hidden, static structural joints. Toughened cyanoacrylates. Fast fixture on small parts, useful for tacking and jigless assembly, but limited durability under thermal cycling, moisture, and peel. Silane-modified polymers and polyurethanes. Stay flexible, tolerate wide temperature ranges, and bridge dissimilar materials well. Slower cure, lower ultimate strength. Incure Uni-Weld Line Incure's Uni-Weld UV-curable adhesives cover the acrylate options for plastic-to-metal work. They cure in seconds under UV or LED light, maintain clarity and non-yellowing character in the appropriate grades, and are 100 percent solids with low shrinkage. High-elongation grades give the flexibility a thermal-mismatch joint needs; rigid grades give maximum shear on a well-fitted static joint. The Uni-Weld plastic bonder guide and the glass and metal bonder guide cover grade selection for each substrate. For a recommendation against a specific plastic-and-metal pair, Email Us with both material names and the joint drawing. Surface Preparation Metal: degrease, abrade to a uniform profile, remove loose oxide, bond promptly. Conversion-coated or anodized aluminum is more durable than bare. Plastic: identify the polymer, clean with isopropyl alcohol, plasma or corona treat low-energy grades, verify with a dyne pen. Joint Design Checklist Load the adhesive in shear, not peel. Size the bond area for the working…

When a plastic-to-metal joint has to carry structural load, not just hold a cover in place, the margin for error narrows. The adhesive has to develop high shear strength, keep it after thermal cycling and humidity exposure, and do it on two surfaces that behave nothing alike. This is how to specify that joint. What "Structural" Demands A structural bond transfers working loads between components as if they were one part. That means: High lap-shear strength, often in the thousands of psi on metal substrates. Retained strength after aging, not just a high initial pull value. Predictable failure mode. A structural joint should fail cohesively, through the adhesive, at a known load, rather than peeling suddenly off a surface. Resistance to creep under sustained load at the maximum service temperature. The Dissimilar-Material Problem Metals expand 12 to 23 ppm per degree C. Engineering plastics run 50 to 100 ppm per C or higher. In a structural joint that difference is a real force. Across a 60 C swing on a 100 mm bond, the ends of the joint can see tens of micrometers of differential movement, applied as cyclic shear every time the assembly heats and cools. A joint that is strong but brittle will accumulate damage at the bond edges and fail early. The mechanism is covered in how CTE mismatch causes adhesive bond failure. The design answer is not always maximum rigidity. It is enough strength for the load, with enough elongation to survive the thermal shear, over a bond area sized with margin. Incure Uni-Weld Line Incure's Uni-Weld UV-curable adhesives develop high bond strength on metals, glass, and ceramics, with grades reaching several thousand psi in lap shear on prepared metal. They cure tack-free in seconds under a UV source such as the Incure F200 flood lamp, which keeps fixture time short even on a structural line. Formulations are 100 percent solids with no VOCs and low cure shrinkage, so the joint does not build in stress as it sets. For the plastic face, the Uni-Weld Plastic Bonder grades target polycarbonate, ABS, and PMMA, with acid-free options for stress-crack-sensitive polymers. Matching a grade to the substrate and the mechanical demand is covered in the Uni-Weld plastic bonder guide, and the glass and metal bonder guide covers the metal side. For a grade recommendation against your load case, Email Us with the joint geometry, working load, and temperature range. Surface Preparation Is Not Optional for Structural Joints Metal: Degrease with a clean solvent. Grit-blast or abrade to a uniform anchor profile. Remove all loose oxide and blast media. On aluminum, a conversion coating or a stable anodize layer gives the most durable interface. Bond within the working window before oxide re-forms. Plastic: Confirm the polymer. Clean with isopropyl alcohol. Plasma or corona treat low-energy grades to above 40 mN/m. Verify surface energy before releasing the batch. Skipping or shortcutting prep is the most common cause of a structural plastic-to-metal joint that passes at the bench and fails in…

Joining metal to plastic is one of the most common dissimilar-material problems in manufacturing, and one of the most failure-prone. The two substrates have almost nothing in common: different surface chemistry, different stiffness, and thermal expansion rates that can differ by a factor of ten. An adhesive is usually the right answer, but only if it is chosen for that mismatch. Why Metal-to-Plastic Joints Fail Thermal expansion mismatch. Aluminum expands about 23 ppm per degree C. Steel is around 12. Many engineering plastics run 50 to 100 ppm per C, and filled or unfilled variations widen the spread further. Heat a bonded assembly and the plastic grows several times more than the metal. A rigid adhesive locks the two together and the bond line, or the plastic surface, takes the strain. This is the dominant field failure, and the design responses are laid out in how CTE mismatch causes adhesive bond failure. Low-energy plastic surfaces. Polyolefins, acetal, and many filled thermoplastics have surface energies below what an adhesive needs to wet properly. Without treatment, the adhesive beads instead of spreading and the bond is weak from the start. Metal surface condition. Bare aluminum carries a loose oxide that keeps re-forming. Steel carries mill scale and oil. Neither bonds well as received. Surface Preparation Plastic: Identify the polymer first. Clean with isopropyl alcohol. For low-energy plastics, add plasma or corona treatment to raise surface energy above 40 mN/m, or use a compatible adhesion promoter. Verify with a dyne pen. Metal: Degrease, then abrade or grit-blast to a uniform profile and remove loose oxide. Anodized or conversion-coated aluminum bonds more reliably than bare. Bond soon after preparation. Incure Uni-Weld Plastic Bonder Line Incure's Uni-Weld Plastic Bonder grades are UV and visible-light-curable acrylates developed for polycarbonate, ABS, PMMA, and similar engineering plastics, and they bond well to prepared metal on the other face of the joint. They cure in seconds under UV or LED light, which suits high-volume assembly, and several grades offer high elongation, in the range of a few hundred percent for the more flexible options, so the joint can absorb the differential movement between plastic and metal instead of resisting it. Acid-free formulations in the line are compatible with stress-sensitive plastics such as polycarbonate, where an acidic adhesive can trigger environmental stress cracking. Grade selection is driven by the plastic being bonded and the mechanical demand on the joint; the Uni-Weld plastic bonder selection guide walks through matching a grade to the substrate. For help choosing a grade for a specific plastic-to-metal pair, Email Us with both material names and the joint drawing. Joint Design for the Mismatch Use a compliant adhesive. Elongation to failure well above the expected differential strain lets the bond line shear and recover. Keep the bond line generous. A thicker, uniform gap, around 0.2 to 0.5 mm, distributes strain better than a thin one. Set it with spacers. Favor shear over peel. Lap and sleeve joints load the adhesive in its strong direction. Avoid designs…

Some glass-to-metal joints have to do two jobs at once: carry real structural load and stay optically clean where they show. A watch crystal seated in a bezel, a sight glass in a housing, a lens bonded to a metal mount. Getting both from one adhesive means paying attention to the cured film properties, not just the headline bond strength. What "High Clarity" Actually Requires A bond line looks clean when three things are true. The cured adhesive is colorless and stays that way. Its refractive index is close enough to the glass, roughly 1.47 to 1.55, that the interface does not reflect or refract noticeably. And the film is free of haze, bubbles, and cure-shrinkage distortion. Color stability is the one that trips people up. Many adhesives look clear on day one and turn amber after months of light exposure because their photoinitiator residues or the base resin degrade under UV. For a joint near a window or under lighting, yellowing resistance has to be a specified requirement, not an assumption. Low cure shrinkage matters too: a grade that pulls in as it sets creates lensing and edge stress that show up as visible distortion. What "High Strength" Requires on Glass Glass fails in surface tension at a fraction of the stress metal tolerates. A strong glass joint therefore comes from spreading load over area, not from a small high-strength dot. Key contributors: Adequate bond area sized for the working load plus the thermal shear from expansion mismatch. A controlled, uniform bond line, typically 0.1 to 0.3 mm, thick enough to distribute strain, thin enough to cure fully and quickly. Some compliance in the cured adhesive so it shears and recovers rather than transmitting peak stress into the glass surface. A smooth fillet at the edge to avoid stress concentration. Glass expands about 9 ppm per degree C, aluminum about 23 ppm per C, stainless around 17 ppm per C. Over the service temperature range the metal moves more, and the bond line takes that difference as shear. The design responses are covered in how CTE mismatch causes adhesive bond failure. Incure Uni-Weld UV Glass and Metal Bonder Line Incure's Uni-Weld UV Glass & Metal Bonder grades are formulated for this clarity-plus-strength requirement. They cure in seconds under UV or visible light to a clear film, hold high bond strength on glass, metal, and ceramic, and are 100 percent solids with no VOCs and no solvent-loss shrinkage. Good thermal and moisture resistance supports outdoor and wash-down use. Grades differ in viscosity and cured modulus. Rigid grades give the highest shear on a well-fitted joint; toughened grades trade some peak strength for the elongation needed on a wide-temperature glass-to-metal assembly; thixotropic grades such as 2204VT stay put on a vertical bezel or mount. The Uni-Weld selection guide explains how to read the tables. Where a surface activator is used, initial strength builds within about ten minutes and most of the ultimate strength within 24 hours. For a grade recommendation against…