A formed-in-place gasket, or FIPG, is a liquid or paste sealant dispensed directly onto a component and cured in position to create a custom-fit seal. Unlike a die-cut gasket made separately and installed by hand, an FIPG becomes an integral part of the assembly, which changes how engineers approach sealing.

Defining the Formed-in-Place Gasket

An FIPG starts as a flowable material, most often a silicone, polyurethane, or acrylic, that is applied in a precise bead along a sealing surface and then cured. The bead follows the exact geometry the joint requires, so the seal matches the part rather than the part being designed around a standard gasket profile.

Dispensing is usually automated. A robotic or XY-gantry system applies a repeatable bead volume and path, which controls the two variables that matter most for seal quality: where the material sits and how much of it there is.

How the FIPG Process Works

Most FIPG lines run in three stages:

1. Dispensing. An automated system lays a bead of sealant onto the flange or groove. Bead width and height are set by nozzle size, flow rate, and traverse speed.
2. Mating. In compression FIPG (also called cure-in-place), the second part is assembled onto the wet bead, which spreads the material and fills surface irregularities. In true form-in-place designs, the bead is cured before assembly and acts as a resilient gasket on its own.
3. Curing. The material solidifies by one of several mechanisms:
4. Room-temperature vulcanizing (RTV), driven by ambient moisture.
5. Heat curing in an oven, which shortens cycle time.
6. UV curing, which fixes the bead in seconds and suits high-speed lines. Matching lamp output to the sealant is covered in our guide to choosing a UV lamp for resin and sealant curing.
7. Dual cure, combining UV with a moisture or heat secondary mechanism so shadowed sections still harden.

Once cured, the bead forms a continuous barrier against fluids, gases, dust, and airborne contaminants.

Why Manufacturers Use FIPG

The shift toward FIPG in electronics, powertrain, lighting, and enclosure manufacturing reflects several practical gains:

• Design freedom. The bead can follow complex, multi-level, or tightly spaced flange geometry that a cut gasket cannot cover economically. A compact hydraulic manifold with internal channels can be sealed along routes that would be impossible to tool as a discrete part.
• Fewer leak paths. A seamless bead adhered to the substrate removes the seams, joints, and compression-set behavior that let pre-cut gaskets leak over time.
• Lower inventory and labor. One cartridge or drum of sealant replaces a family of gasket part numbers, and automated dispensing removes manual placement and the errors that come with it.
• Less waste. FIPG is additive, so material is placed only where it is needed rather than die-cut from sheet stock with the offcuts scrapped.
• Tailored durability. Formulations can be selected for chemical exposure, thermal range, or vibration, extending the service life of the sealed assembly.

Three Related Approaches

FIPG is one of a family of dispensed-seal methods, and the terms are often confused. In a true formed-in-place gasket, the bead is dispensed and fully cured before the two halves are assembled, so it behaves like a resilient pre-made gasket that happens to be a perfect fit. In a cure-in-place gasket, the bead is dispensed and the parts are assembled while it is still wet, so the material spreads and cures in compression against both surfaces. A related method, the pre-formed in-place gasket, dispenses onto one part and cures it, then relies on adhesion to keep it located during handling. The choice affects clamp-load requirements, rework, and how forgiving the process is to flange flatness.

Bead Geometry and Compression

A dispensed bead is usually round or trapezoidal in cross-section, and the design target is a compression of 15 to 40 percent once the joint is closed. Too little compression leaves the seal sensitive to flange waviness; too much can extrude material into the bore or split the bead. Flange land width should be at least two to three times the bead width so the compressed material has somewhere to go. Hard stops or a controlled bead height keep compression repeatable across a production run.

Material Property Ranges

Silicone FIPG typically serves from around -60°C to 200°C, with some grades higher, and resists ozone and weathering. Polyurethane runs cooler, roughly -40°C to 90°C, but offers better abrasion and tear resistance. Acrylic and UV-curable systems give the fastest cure and good clarity but a narrower temperature band. Elongation at break for a gasket-grade material is commonly 150 to 400 percent, which is what lets the seal follow joint movement without tearing.

Selecting an FIPG Material

The right chemistry depends on the operating environment. Silicone handles wide temperature swings and weathering. Polyurethane offers abrasion resistance and toughness. Acrylic and UV-curable systems give the fastest line speeds. Substrate compatibility matters too, since surface energy and any release residue on the flange determine whether the bead adheres or simply sits on top.

Differential thermal expansion between the housing and its cover also loads the seal on every heat cycle, a failure mechanism explained in our article on how CTE mismatch causes adhesive and seal failure. A gasket material with enough elongation absorbs that movement instead of tearing.

Putting FIPG Into Production

Before committing a line, validate the process on production parts: confirm bead adhesion after the intended cleaning step, check cure completeness in the deepest shadowed section, and run sealed assemblies through the pressure and temperature cycles the product will face. Dispensing parameters, flange rigidity, and gap control should all be set during design rather than corrected on the floor.

If you are evaluating FIPG for a new assembly and need help matching a sealant chemistry and cure method to your substrate and cycle time, Email Us with your flange drawings and environmental requirements.

Formed-in-place gaskets give manufacturers a precise, repeatable, low-inventory way to seal complex assemblies. Understanding the dispensing, mating, and curing steps, and choosing a material suited to the environment, is what turns the technology into a reliable production process. Contact Our Team to discuss your sealing application.

Visit www.incurelab.com for more information.