A pre-cut gasket has to be stocked, handled, and seated by hand or machine before it can seal anything. A form-in-place gasket skips all three steps — it’s dispensed directly onto the part and cured in place, and when that cure happens in seconds under UV light instead of hours at room temperature, the whole sealing operation stops being a bottleneck.
What Light-Curable FIPG Actually Is
Form-in-place gaskets (FIPG) are liquid sealants dispensed directly onto a surface or into a groove, where they cure into a resilient elastomeric seal — no die-cutting, no separate part number, no manual seating. Light-curable FIPGs are a specific subset formulated with photoinitiators that respond to UV or visible wavelengths: exposure to a high-intensity light source drives rapid polymerization, turning the liquid into a solid elastomer in seconds rather than the hours a room-temperature-vulcanizing (RTV) sealant needs.
Most formulations are built on silicone or acrylate chemistry. Acrylate systems bond aggressively to plastics and metals and cure fast; silicone systems trade some cure speed for superior thermal stability and flexibility across wide temperature swings. Both are engineered for a low compression set so the seal holds its shape and clamping force over the product’s service life.
Why FIPG Beats Die-Cut Gaskets and O-Rings
Dispensing exactly the material a seal needs eliminates the inventory of stocked gasket shapes and the scrap that die-cutting generates. Because the bead is dispensed rather than molded, FIPG supports complex 3D patterns, variable thickness, and geometries a physical gasket simply can’t replicate. Cure happens in seconds rather than the hours an RTV sealant needs, so parts move to the next station immediately. And because the seal forms directly on the substrate, it bonds intimately to the surface — removing the shifting or improper seating that causes leaks in manually installed O-rings.
Where Light-Curable FIPG Gets Used
Automotive electronics and EV components. Battery management systems, sensors, and ECUs need protection from moisture, dust, and vibration in harsh under-hood environments — FIPG delivers a fast, reliable seal for these enclosures.
Consumer electronics. Smartphones, tablets, and wearables need IP67/IP68 water resistance from an ultra-thin gasket bead that doesn’t add bulk, and the rapid cure supports the throughput these lines demand.
Renewable energy equipment. Inverter housings and junction boxes on solar and wind installations need weatherproof seals that hold up through years of outdoor thermal cycling — a use case where FIPG’s low-shrinkage, UV-stable chemistry has to tolerate the same CTE-mismatch stresses that cause bond failure in any dissimilar-material joint exposed to repeated heating and cooling.
Aerospace and defense. Extreme pressure and temperature swings demand gaskets engineered for low outgassing and high chemical resistance to keep critical systems sealed.
Dispensing and Curing Equipment
Precision dispensing drives bead consistency, which drives seal quality. Needle valves suit low-to-medium viscosity materials and simple patterns; diaphragm valves handle high-speed, consistent-volume work; auger valves manage high-viscosity or filled materials; and jetting valves allow non-contact dispensing at very high speed for intricate electronic assemblies. Vision-guided robotic systems can track the part in real time, keeping placement accurate to sub-millimeter tolerances.
On the cure side, UV LED systems have largely replaced mercury vapor lamps: LEDs run cool with minimal IR output (important for heat-sensitive plastics), switch on instantly with no warm-up cycle, tune to the specific wavelength a formulation’s photoinitiator needs, and last over 20,000 hours against roughly 1,000 for a mercury bulb. Incure’s CDM™ UV conveyor pairs LED and conventional flood heads for exactly this kind of in-line gasket-curing step, and the Uni-Seal™ line covers the gasket-material side across a broad compression-hardness range.
Performance Metrics That Matter
Compression set measures how well a material returns to its original thickness after sustained compression — a high compression set means the gasket takes a permanent set and loses sealing force over time. Adhesion strength matters whenever the design calls for the gasket to bond to at least one mating surface rather than seal purely by compression; testing against the actual substrate (anodized aluminum, glass-filled nylon, polycarbonate) is essential before locking in a material. Environmental resistance depends on exposure: acrylate chemistries generally handle oils and fuels better, while silicones excel in high-UV, high-temperature outdoor service.
Design Guidelines for a Reliable Seal
A groove roughly 1.5 times the width of the dispensed bead accommodates material displacement during compression. Because cure depends on light reaching the bead, any shadowed recess or undercut needs either a repositioned light source or a dual-cure material with a secondary moisture-cure path. Low-surface-energy plastics like polypropylene or polyethylene often need a corona or plasma treatment before dispensing to achieve adequate adhesion. If you’re designing a groove or evaluating a dual-cure option for a shadowed geometry, Email Us for application-specific guidance.
Troubleshooting Common Issues
Incomplete cure usually traces to insufficient intensity or a wavelength mismatch — verify output with a radiometer against the material’s spec. Bead tailing or stringing is typically a dispensing-valve snuff-back setting or a viscosity issue solved by minor heating at the tip. Air entrapment calls for proper degassing and leak-free supply lines. Poor adhesion is most often surface contamination — clean and dry the part, and add a primer if the problem persists.
Getting groove design, dispensing method, and cure equipment aligned before the line runs at full rate is what separates a smooth FIPG rollout from one full of rework. Contact Our Team to work through material selection for your specific enclosure and seal geometry.
Visit www.incurelab.com for more information.