Epoxy

Epoxy Glue for Metal: How Structural Bonding Compares to Welding

For metal assemblies, the joining method sets the durability of the finished product. Epoxy adhesives have become a standard alternative to welding, soldering, and fasteners because they spread load evenly, join dissimilar metals, and seal the joint against corrosion. Where Epoxy Beats Mechanical Joining Even stress distribution. A weld or a bolt concentrates load at a point or a line. An epoxy bond spreads it across the entire overlap area, so a well-designed joint can carry load up to the strength of the parent metal without a local stress riser. Dissimilar materials. Welding needs compatible metals. Epoxy bonds aluminum to steel, metal to composite, metal to ceramic, and metal to engineering plastic, which opens up lightweight multi-material designs. Corrosion control. Epoxy forms an insulating barrier between two metals, blocking the galvanic corrosion that occurs when dissimilar metals touch in the presence of moisture. It also seals the joint against water, salt, and chemicals. Fatigue life. A slightly flexible adhesive layer absorbs and redistributes cyclic stress better than a rigid weld or fastener, extending fatigue life in vibrating assemblies. No heat distortion. Bonding introduces no heat-affected zone, so thin-gauge panels stay flat and heat-treated properties are preserved. Clean appearance. No rivet heads, bolt patterns, or weld beads, which matters for visible surfaces. For a direct comparison on load capacity, see which is stronger for heavy-duty repairs. Why Epoxy Adheres Well to Metal Epoxy adhesives are thermosetting polymers. Mixing resin with hardener starts a reaction that builds a dense cross-linked network gripping the prepared metal surface. Their usefulness on metal comes from strong molecular adhesion to steel, aluminum, brass, copper, and titanium; high shear and peel strength once cured; resistance to water, oils, fuels, and solvents; a broad service-temperature range depending on formulation; and enough viscosity to fill gaps and voids on imperfect surfaces. Surface Preparation Decides the Result Most bond failures on metal are preparation failures, not adhesive failures. The steps that matter: degrease with a clean solvent to remove oil and cutting fluid; abrade with sanding or grit blast to remove oxide and add mechanical key; wipe again with fresh solvent to clear abrasion debris; and bond promptly before a new oxide layer forms, especially on aluminum. A chemical etch or conversion coating raises durability further on critical joints. Matching Thermal Expansion When epoxy joins two metals, or a metal and a non-metal, with different expansion rates, every temperature change shears the bond line. Too rigid an adhesive cracks or debonds at the edges over many cycles. A toughened or semi-flexible epoxy absorbs that movement. The mechanism and how to design around it are covered in how CTE mismatch causes adhesive bond failure. Choosing a Formulation Two-part room-temperature epoxy suits repair, maintenance, and low-volume assembly. It gives working time for alignment and cures without an oven. One-part heat-cure epoxy suits automated high-volume lines. It needs no mixing, has a long shelf life when refrigerated, and delivers high strength after an oven cycle. UV-cure adhesives fix parts in seconds where at…

Comments Off on Epoxy Glue for Metal: How Structural Bonding Compares to Welding
June 18, 2025
Conformal Coatings

High Voltage Silicone Conformal Coatings

As electronics get denser and run at higher voltages, the insulation between traces has less physical room and more electrical stress. Silicone conformal coating is chosen for these boards because it combines high dielectric strength with the flexibility to survive thermal cycling. The Role of Conformal Coating at High Voltage A conformal coating is a thin polymeric film that follows the shape of a printed circuit board and its components. It seals the assembly against moisture, dust, chemicals, and vibration. On a high-voltage board it does more: it replaces unreliable air gaps with a solid dielectric. High-voltage electronics in automotive, aerospace, industrial automation, and power generation are exposed to humidity, contamination, temperature extremes, and mechanical shock. Any of these can trigger insulation breakdown, arcing, tracking, or a short. A coating raises insulation resistance between conductors, allowing tighter spacing and more compact designs, while sealing out the contaminants that start corrosion and conductive paths. In a discharge event it also limits the carbonized tracking that would otherwise shorten creepage distance. Why Silicone Suits High Voltage Dielectric strength. Silicone films hold off high voltages across a thin applied layer, maintaining insulation integrity in high-power systems. Wide temperature range. Silicones stay stable from around minus 60 C to well above 200 C, so they perform in engine bays, inverters, and outdoor equipment without softening or embrittling. Flexibility. Unlike rigid acrylic or epoxy films, cured silicone stays elastic. It absorbs the expansion and contraction of thermal cycling and the strain of vibration without cracking or delaminating. Moisture resistance. Silicone forms an effective barrier against humidity and condensation, protecting against corrosion and leakage current. Adhesion. Silicone coatings bond well to common board substrates and component bodies, giving continuous protection. Incure Pyra-Sil silicone conformal coatings are formulated for rigid and flexible boards exposed to contamination and vibration, and are available in several viscosities for spray, dip, and selective application. For help choosing a viscosity and cure path, Email Us. Thermal Cycling Is the Main Stress A coating on a board that mixes materials with different expansion rates is loaded every time the assembly heats and cools. A rigid film concentrates that stress at component edges and eventually cracks or peels, and a lifted edge becomes a moisture trap. This is the same mechanism described in how CTE mismatch causes adhesive bond failure. Silicone's elasticity is what lets it ride out thousands of cycles where a hard coating would fail. Cure Options Silicone conformal coatings cure by moisture (condensation) at room temperature, by heat for faster line speeds, or by UV for grades formulated with photoinitiators. UV cure is fastest but leaves shadowed areas under tall components uncured unless a secondary mechanism is present. Where UV cure is used, the lamp is typically a near-UV flood source; flood lamps are matched to area and intensity, and output should be checked periodically because UV source intensity declines over service life. Creepage, Clearance, and the Coating High-voltage design rules set minimum creepage (distance along a surface) and clearance (distance…

Comments Off on High Voltage Silicone Conformal Coatings
June 18, 2025
Conformal Coatings

Conformal Coating for High Voltage Applications

At high voltage, the air gap between two traces stops being reliable insulation. A conformal coating raises the effective dielectric strength of the board, and choosing the wrong one invites arcing, tracking, and dielectric breakdown in service. Why High Voltage Changes the Requirement A conformal coating is a thin polymeric film that follows the contours of a printed circuit board and its components, forming a barrier against contaminants. On a low-voltage board its main job is environmental protection. On a high-voltage board it also has to prevent electrical failure. High-voltage assemblies face specific risks. Arcing and flashover can jump between closely spaced conductors. Surface contamination plus humidity creates conductive tracking paths that carbonize over time. The dielectric strength of air alone becomes insufficient as voltage rises, allowing leakage or breakdown across gaps that would be safe at lower potential. A coating fills the space around and between conductors with a solid dielectric of much higher breakdown strength than air, raises insulation resistance, and seals out the moisture and pollution that start tracking. Selection Criteria Dielectric strength is the first specification, expressed in volts per unit thickness. The coating must hold off the working voltage with margin across its applied thickness. Temperature range must cover the full operating and storage extremes without the film softening, embrittling, or losing adhesion. Environmental resistance should match the real exposure: humidity, salt, chemical splash, and UV. Adhesion to the board and components must be strong enough to resist delamination, since a lifted edge becomes a moisture trap and a tracking site. Flexibility versus hardness is a trade-off. A flexible film survives thermal cycling better; a hard film resists abrasion better. Cure method and time have to fit the production line, whether that is heat, moisture, or UV cure. Standards compliance such as IPC-CC-830 and relevant safety-agency recognition should be confirmed for the specific grade. For help matching a coating to a voltage class and environment, Email Us with the board details. Coating Chemistries at High Voltage Silicone offers a wide temperature range, strong moisture and chemical resistance, high dielectric strength, and enough flexibility to handle thermal cycling. It is a frequent default for high-voltage power electronics. Acrylic has good dielectric properties and is easy to apply and rework, but its temperature range and chemical resistance are narrower. Urethane resists abrasion and solvents well and suits harsh mechanical environments. Epoxy is very hard and chemically resistant but rigid, so it needs careful stress management on boards with mixed materials. Thermal Cycling and Coating Stress A rigid coating on a board that combines materials with different expansion rates is stressed on every heat-cool cycle. Stress concentrates at component edges and can crack the film or peel it, opening a path for moisture. The mechanism is the same one described in how CTE mismatch causes adhesive bond failure, and it is the main reason flexible silicone coatings are preferred for wide-temperature high-voltage work. Application and Thickness Control Film thickness drives dielectric performance. Too thin and the breakdown voltage…

Comments Off on Conformal Coating for High Voltage Applications
June 18, 2025
Epoxy / Thermally Conductive

Thermally Conductive Adhesives for Electronic Assembly

Every watt an electronic component draws has to go somewhere, and when it can't escape through the bond line fast enough, it doesn't disappear — it accumulates until the component throttles, degrades, or fails outright. What Thermally Conductive Adhesives Actually Do Thermally conductive adhesives are bonding materials filled with conductive particles — ceramic, aluminum oxide, or metallic fillers — that create a path for heat to move from a component to a heat sink or chassis while still holding the two parts together mechanically. Unlike a standard structural adhesive, the filler package is engineered specifically to maximize thermal transfer without sacrificing bond strength, and many formulations remain electrically insulating even while conducting heat efficiently, which matters when the bonded surfaces sit close to live circuitry. Why Thermal Management Can't Be an Afterthought Heat is the single largest driver of premature failure in dense electronic assemblies. As power density increases and enclosures shrink, the margin for passive convective cooling shrinks with it, and mechanical fasteners alone can't fill the microscopic air gaps between a component and its heat sink — air is a poor thermal conductor, and any gap left unfilled becomes a bottleneck. A properly selected thermally conductive adhesive closes that gap, adds vibration and shock resistance the mechanical fastener alone wouldn't provide, and often eliminates the fastener entirely, saving weight and assembly steps. Selecting the Right Formulation Not every thermally conductive adhesive chemistry behaves the same way. Two-part epoxies generally offer the highest bond strength and the best long-term thermal stability under continuous elevated temperature, which makes them the default choice for power electronics, LED heat-sink bonding, and motor control assemblies. Silicone-based formulations trade some bond strength for flexibility, which helps when the bonded materials have different coefficients of thermal expansion and will expand and contract at different rates during thermal cycling — a mismatch that can crack a rigid bond line over repeated cycles even if the initial bond was sound. If you're weighing epoxy against a more flexible chemistry for a specific substrate pairing, Email Us and we can help you work through the trade-off before you commit to a production process. Where These Adhesives Show Up in Industry LED lighting: bonding emitters directly to heat sinks to extend service life and maintain output. Consumer and industrial electronics: managing heat from CPUs, power ICs, and voltage regulators in compact enclosures. Automotive electronics: dissipating heat in motor control units and battery management systems exposed to under-hood temperatures. Renewable energy systems: managing heat in solar inverters and power conversion hardware running at high continuous current. Industrial automation: maintaining consistent thermal performance in motor drives and control cabinets on a factory floor. Bond Line Thickness Matters as Much as Filler Content Engineers often focus entirely on a formulation's rated thermal conductivity in W/m·K and overlook bond line thickness, but the two interact directly. Thermal resistance across a bonded joint increases with bond line thickness, so a thick, uneven adhesive layer can undermine an otherwise high-conductivity filler package — a thinner,…

Comments Off on Thermally Conductive Adhesives for Electronic Assembly
June 12, 2025
UV Adhesives

Optical Adhesives for Precision Assembly

The adhesive in an optical assembly does more than hold parts together. It becomes part of the light path, so its clarity, refractive index, and dimensional stability under cure directly set the performance of the finished lens, sensor, or fiber connector. What Sets an Optical Adhesive Apart Unlike a general-purpose glue, an optical adhesive is engineered around how it interacts with light: High transmission and low haze. The cured resin passes light across the visible band and often into the near infrared without yellowing or scatter. Controlled refractive index. Grades are formulated to specific index values so the bond line can be matched to glass or a polymer, minimizing reflection and stray light at the interface. Low cure shrinkage. Volumetric shrinkage in the low single-digit percent range keeps stress off delicate components and holds alignment during cure. Environmental durability. A qualified optical bond survives thermal cycling, humidity, and light exposure without clouding or debonding. Fast fixture. UV and visible-light-cure grades reach handling strength in seconds, which suits active alignment and automated assembly. Where Optical Adhesives Are Used Displays and electronics: optically clear bonding of cover glass, touch panels, and sensor stacks to remove air gaps that cause glare and reduce contrast. Fiber optics and telecom: anchoring fibers in ferrules and bonding connector components for low-loss, stable joints. Cameras and imaging: cementing lens doublets, bonding prisms, and fixing image sensors to their mounts. Automotive sensing: bonding lenses and windows in driver-assistance cameras and lidar modules that face wide temperature swings and vibration. Instrumentation: assembling beam splitters, filters, and windows in analytical and metrology equipment. The Incure Optik Series Incure's Optik series covers UV and visible-light-cure optical adhesives across a range of viscosities and cured properties, including grades 1702, 7018, 7200, 7210, 7213, 7263, 7288H, and 7613. Selection usually comes down to a few variables: Viscosity. Low-viscosity grades wick into narrow gaps and seal fiber ferrules; medium and higher-viscosity grades stay in place on a lens edge or a larger bond area and give higher structural strength. Refractive index target. Choose the grade whose index is closest to the substrates being joined for the lowest interfacial reflection. Cure path. Where the bond line is fully exposed, a UV-only grade is simplest. Where part of the joint is shadowed by an opaque mount, a grade with a secondary cure mechanism finishes the hidden region. Service environment. Grades differ in glass transition temperature, moisture resistance, and thermal-cycling durability; match these to the qualification the assembly must pass. Published tensile figures for optical adhesives are often limited by the substrate rather than the adhesive, since a glass or polymer coupon can fracture before the bond line does. Treat strength numbers as a system property, not the adhesive's ceiling. Email Us with your substrates, gap size, index target, and whether the joint is shadowed, and Incure's team can shortlist a grade. Getting a Repeatable Optical Bond Clean rigorously. Even a trace film of oil or a fingerprint shows up as haze or a weak spot. Wipe…

Comments Off on Optical Adhesives for Precision Assembly
June 12, 2025
UV Adhesives

Glue TPU to PLA

Multi-material design pairs TPU for flexibility and grip with PLA for rigid, easily printed structure. The bond between them is where projects fail, because the joint has to accommodate TPU movement against a stiff, low-surface-energy PLA face. Why the TPU-PLA Joint Is Hard TPU is a rubber-like elastomer used for flexible housings, gaskets, and ergonomic grips. PLA is a rigid thermoplastic used for structural parts, prototypes, and fixtures. Bonding them runs into three problems at once: Flexibility against rigidity: the bond must flex with the TPU without cracking away from the PLA. Low surface energy: both plastics resist wetting, so adhesives struggle to spread and form a strong interface. Chemical compatibility: an adhesive tuned for one plastic often bonds poorly to the other. PLA adds a further constraint. It softens near 55 to 60 degrees C, so any bonded assembly and its cure schedule must stay well below that. Adhesive Options Polyurethane-based adhesives. Generally the leading option, combining inherent flexibility with adhesion to a wide range of plastics. They form resilient bonds that tolerate dynamic stress. Solvent-based systems. Certain formulations bite into both surfaces chemically. Test first, since an aggressive solvent can craze PLA. Flexible cyanoacrylates with a primer. Fast and strong for small areas or tacking. The primer prepares the TPU face; the cured line is comparatively stiff, so keep it away from parts that flex hard. Flexible UV-curable adhesives. For translucent parts where light reaches the bond line, a high-elongation UV grade cures in seconds and stays clear. Surface Preparation Clean both faces with isopropyl alcohol to strip oils, dust, and print residue, then dry fully. Roughen both surfaces with 220 to 400 grit. This matters most for PLA, where layer lines alone are not enough mechanical key. Remove sanding dust. Prime the TPU if the adhesive specifies it. Apply thin, mate immediately, and clamp or weight through the initial set. Cure fully before loading, at a temperature safely below PLA's softening point. Design the Joint for Movement Most TPU-to-PLA failures are peel fatigue at the bond edge, not adhesion loss. Put the adhesive in shear: Use a lap joint with generous overlap rather than a butt joint. Add a mechanical feature where possible, such as a captured lip, a dovetail, or a through-pin, so the adhesive is not the only thing resisting peel. Account for differential expansion between the soft and rigid materials. Our guide on how CTE mismatch causes adhesive bond failure explains the cyclic stress this adds. Where TPU-to-PLA Bonding Is Used Multi-material prototypes: functional parts that combine flexible gaskets, hinges, or grips with rigid structure. Robotics and automation fixtures: flexible joint covers or cable guides on rigid frames. Consumer product design: soft-touch zones on rigid housings. Protective equipment: rigid impact shells with flexible cushioning elements. Tooling and jigs: compliant contact pads on rigid locating bodies. Qualifying the Bond Test on parts made the way production parts are made, with the same infill, orientation, and surface prep. Pull and peel a sample set to a…

Comments Off on Glue TPU to PLA
June 11, 2025
UV Adhesives

Glue TPU to TPU

Thermoplastic polyurethane earns its place in flexible phone cases, shoe soles, industrial seals, and protective covers through elasticity, abrasion resistance, and toughness. Those same traits make bonding TPU to itself difficult: the joint has to keep flexing without the bond line cracking. Why Bonding TPU to TPU Is Tricky TPU stretches and returns to shape. Most common adhesives cure into a rigid solid that cannot follow that movement, so the bond delaminates or cracks the first time the part flexes hard. The result is a stiff patch that has lost the properties the designer chose TPU for, often with a visible brittle glue line. The goal is an adhesive that both adheres to the low-surface-energy TPU surface and cures with elastic properties close to the substrate, so the joint moves as one piece. Adhesive Types for Flexible TPU Joints Polyurethane-based adhesives. Usually the closest match. They adhere well to TPU and cure flexible, forming resilient bonds that survive repeated dynamic stress. Solvent-based systems. Some formulations soften the TPU surface so the two faces partly fuse. These can be very strong but need careful application and good ventilation. Flexible-grade cyanoacrylates with a primer. Standard instant adhesives are brittle, but flexible grades used with a TPU primer give fast, strong bonds for small areas or tacking. Flexible UV-curable adhesives. For transparent TPU and thin-film work, a UV-curable grade formulated for high elongation cures in seconds and stays clear, provided light can reach the bond line. Surface Preparation Steps Clean thoroughly. Wipe both surfaces with isopropyl alcohol to remove mold release and contaminants that block adhesion, then let them dry completely. Abrade lightly. Scuff the bond area with 320 to 400 grit to raise surface area, then remove all dust. Prime if specified. If the chosen adhesive calls for a TPU primer, apply it per the manufacturer's instructions and observe the flash-off time. Apply a thin layer. Coat one face evenly. Excess adhesive weakens the bond and slows cure. Press and hold. Bring the faces together immediately and clamp or weight them through the initial set. Cure fully. Let the adhesive reach full strength before loading the joint. Cure times vary widely by chemistry. Design the Joint to Flex A TPU-to-TPU bond most often fails as a fatigue crack, not a clean adhesion loss, because the bond line is loaded in peel every time the part bends. Reduce that risk: Use a lap or scarf joint with generous overlap so the adhesive works in shear. Avoid sharp butt joints that concentrate stress at one edge. Keep the bond line thin and uniform; a thick, uneven line has weak spots. Where the assembly also sees heat, account for expansion. Our guide on how CTE mismatch causes adhesive bond failure explains why cyclic thermal stress adds to mechanical fatigue. Where TPU-to-TPU Bonding Is Used Joining sections of flexible tubing, bellows, and protective boots into longer or branched assemblies. Building multi-part seals and gaskets from cut TPU stock. Repairing splits in TPU covers, cases, and inflatable…

Comments Off on Glue TPU to TPU
June 11, 2025
UV Adhesives

Bonding Thermoplastic Polyurethane (TPU) to ABS

Joining a flexible material to a rigid one is one of the harder problems in plastics assembly. TPU moves under load; ABS does not. An adhesive that bonds well to both has to grip a low-surface-energy elastomer on one face and a rigid engineering plastic on the other, then hold while the two substrates respond differently to every stress cycle. Why the Joint Is Difficult TPU is prized for elasticity, abrasion resistance, and grip, appearing as seals, soft-touch overmolds, protective bumpers, and footwear components. ABS is tough and rigid, used for housings, structural frames, and enclosures. The problem in bonding them is twofold. Their surface energies and chemistries differ, so a single adhesive rarely wets both equally well. And because TPU flexes while ABS stays put, the bond line sees continuous shear and peel loading that a brittle adhesive fails quickly. Adhesive Types That Work Polyurethane-based structural adhesives. Often the closest match, being inherently flexible with good adhesion to both substrates and the resilience to survive dynamic loading. Plastic-specific cyanoacrylates with a primer. Fast and strong, but the cured line is comparatively rigid, so this suits small static joints rather than areas that flex. The primer conditions the TPU surface and is essential. UV-curable acrylate adhesives. Where the joint geometry lets light reach the bond line and one part transmits UV, these cure in seconds and allow precise alignment first. Grade selection matters: a high-elongation formulation is needed so the cured bond can move with the TPU. Surface Preparation Preparation drives the result more than the adhesive choice. Clean both faces with isopropyl alcohol and let them dry. Lightly abrade with 220 to 320 grit to add mechanical key, then remove the dust. TPU in particular benefits from a primer or a brief surface treatment such as plasma or flame, because its low surface energy resists wetting. Apply a thin, even adhesive layer, mate the parts immediately, and hold firm even pressure through the initial cure. Do not load the joint until cure is complete. Email Us with your TPU grade, ABS grade, and whether the joint flexes in service, and Incure's team can point you to a compatible adhesive and prep sequence. Incure Adhesives for the ABS Side Incure's Uni-Weld plastic bonder line is formulated for ABS along with PC and PMMA. Within that line, grade selection is mostly about cured stiffness: Uni-Weld 1054 and 1072, low-viscosity fast-fixturing grades for high-volume work. Uni-Weld 1435, a mid-elongation grade near 80 percent for joints that need to give slightly rather than stay rigid. Uni-Weld 1417, a high-elongation grade near 346 percent for joints where the bond line must flex substantially with a moving TPU component. Uni-Weld 1444, 1453, and 1483, higher viscosity and hardness for gap filling and rigid structural joints. TPU itself is not one of the plastics this line is documented against, so confirm compatibility on your specific TPU with a sample bond before committing a design. TPU chemistry varies widely between shore hardnesses and suppliers. Common Applications TPU-to-ABS…

Comments Off on Bonding Thermoplastic Polyurethane (TPU) to ABS
June 11, 2025
UV Adhesives

Bonding Thermoplastic Polyurethane Parts

Thermoplastic polyurethane rewards designers with rubber-like stretch and abrasion resistance, then punishes them at the bond line. TPU flexes under every load cycle, and an adhesive that cannot move with it peels away at the edge. What Makes TPU Hard to Bond TPU sits between rubber and rigid plastic. That dual nature is why it appears in seals, soft-touch overmolds, protective bumpers, footwear, and flexible enclosures, and also why it resists adhesion. Two properties drive the difficulty: Low surface energy: many TPU grades measure below 38 dynes per centimeter, so most adhesives bead up rather than wetting the surface. Continuous strain: the bonded area sees repeated shear and peel loading as the part flexes, which quickly fatigues a brittle bond. TPU is also sold as two chemistries. Polyester-based grades resist oils and abrasion but hydrolyze in hot, humid service. Polyether-based grades resist moisture better. A bond qualified on one family is not automatically valid on the other, so identify the exact grade, not just "TPU," before selecting an adhesive. Adhesive Options Polyurethane structural adhesives. Often the closest chemical match. They stay flexible after cure and carry dynamic loads without cracking, which suits seams and joints that flex in service. Flexible-grade cyanoacrylates with a primer. Fast and strong for small static joints. The primer conditions the low-energy surface and is not optional. The cured line is comparatively stiff, so this is a poor choice where the joint bends repeatedly. UV-curable acrylate adhesives. Where the joint geometry lets light reach the bond line and at least one part transmits UV, these fixture in seconds and allow alignment first. Choose a high-elongation grade so the cured bond can stretch with the TPU. Surface Preparation Preparation controls the outcome more than the adhesive brand. Work through these steps: Clean: wipe both faces with isopropyl alcohol to remove mold release and handling oils, then let them dry fully. Abrade: scuff the bond area with 220 to 320 grit to add mechanical key, then remove the dust. Treat: because TPU resists wetting, a brief flame or plasma pass, or a manufacturer-specified primer, raises surface energy and markedly improves adhesion. Apply thin: a thin, even adhesive layer bonds better than a thick bead, which traps stress and cures slowly. Fixture: mate the parts immediately and hold firm, even pressure through the initial set. Do not load the joint until cure is complete. Design the Joint for Movement Most TPU bond failures are fatigue cracks, not adhesion failures. The bond line is being loaded in peel as the material flexes. Redesign so the adhesive works in shear instead: Use a lap joint with generous overlap to spread stress over area. Avoid butt joints, which concentrate stress at a single edge. Where the assembly also sees temperature swings, remember that TPU and a rigid mating part expand at different rates, adding cyclic stress the adhesive must absorb. Our article on how CTE mismatch causes adhesive bond failure covers that mechanism. Where TPU Bonding Shows Up Automotive interiors: soft grips…

Comments Off on Bonding Thermoplastic Polyurethane Parts
June 11, 2025
UV Adhesives / UV Curing Equipments / UV LED Equipments / UV LED Spot Equipments

UV Glue for PCB Assembly and Protection

In electronics manufacturing, every second on the line and every bond on the board matters. Printed circuit boards sit at the core of nearly every device, and the adhesive that secures their components has to cure fast, insulate reliably, and survive years of thermal and mechanical stress. What UV Glue for PCB Means UV glue for PCB refers to single-component acrylic or acrylated-urethane adhesives and coatings that harden within seconds when exposed to ultraviolet light at a matched wavelength, typically 365 nm or 395 nm. The liquid contains monomers, oligomers, and a photoinitiator. When UV photons strike the photoinitiator, it releases free radicals that drive rapid crosslinking, converting the liquid to a solid network without solvent evaporation or applied heat. Because the reaction only starts under light, the adhesive stays workable on the board indefinitely until the operator or the conveyor triggers the cure. That property is the reason UV chemistry fits automated electronics assembly so well. Why the Cure Mechanism Fits PCB Work Traditional two-part epoxies need minutes to hours of fixture time and often a thermal post-cure. On a populated board, that means racks of work-in-process and oven exposure that can stress solder joints or heat-sensitive parts. Cycle time: UV fixture times of 2 to 10 seconds let a board move straight to test or the next station. Low process temperature: UV curing releases little heat, so the adhesive can sit next to electrolytic capacitors, crystals, and plastic connectors without thermal damage. Placement control: unlimited open time lets a pick-and-place head or an operator align a fine-pitch part, verify it, then lock it. Dielectric performance: cured films typically show volume resistivity above 10^14 ohm-cm and dielectric strength in the range of 400 to 500 volts per mil, adequate isolation for closely spaced traces. Common PCB Applications UV-curable materials cover several distinct jobs on a board: Component staking: anchoring tall capacitors, relays, transformers, and connectors so vibration and shock do not fatigue the solder fillet. Wire and coil tacking: immobilizing fine lead wires and coil terminations to provide strain relief. Conformal coating: a thin acrylic layer over the assembly that resists humidity, dust, and airborne contaminants. Many UV conformal coatings include a fluorescing tracer so coverage can be inspected under blacklight. Glob-top and dam-and-fill: encapsulating wire-bonded die or bare chips. Tamper indication: a cured dot over an adjustment screw that fractures visibly if disturbed. For plastic housings and connector bodies on the board, Incure's Uni-Weld plastic bonder line is formulated for polycarbonate, ABS, and acrylic, the resins most enclosure parts use. Selecting a Grade Match the adhesive to the job rather than reaching for one general-purpose product: Viscosity: low-viscosity grades (a few hundred centipoise) wick into tight gaps and coat evenly; thixotropic pastes stay put on a vertical surface or a large staking fillet. Cured modulus: a rigid, high-modulus bond resists creep on a structural joint, while a lower-modulus, higher-elongation grade absorbs the stress from thermal cycling between dissimilar materials. Shadow cure: where the bond line is partly hidden…

Comments Off on UV Glue for PCB Assembly and Protection
June 11, 2025