EPDM gaskets sealing headlamps and sensors
EPDM gaskets offer outstanding weather resistance, helping headlamp assemblies and ADAS sensors achieve IP67 waterproofing. Choosing the right gasket is key to preventing condensation, fogged lamps and distorted sensor signals.
Headlamps and ADAS sensors such as cameras, radar and ultrasonic sensors are all located where they are directly exposed to rain, mud and high-pressure car wash water. Even a tiny gap is enough for moisture to get in, causing internal condensation and damaging the electronics.
Properties of EPDM rubber
EPDM offers excellent resistance to ozone, UV and water, and operates in a temperature range of -40°C to 130°C. Its low compression set allows the gasket to retain sealing force for many years. In addition to molded gaskets, EPDM is also available as closed-cell foam with a single-sided adhesive, convenient for automated assembly.
Common gasket types
- Molded profile gaskets for lamp housing grooves.
- Die-cut closed-cell EPDM foam with pre-applied acrylic adhesive.
- Extruded EPDM cord for long gaps.
- Formed-in-place gaskets made from silicone or polyurethane dispensed along a path.
Passing IP67 in the test lab is not enough. The gasket must also stay sealed after thousands of hot-cold cycles and years of sun exposure. That is why compression set matters just as much as hardness. — AMS Materials Engineer
Design and testing
The recommended gasket compression is usually 20% to 40% of its thickness. Too little compression does not seal adequately, while too much causes the gasket to fatigue quickly and increases housing closing force. For small sensor assemblies, pre-adhesived EPDM foam reduces assembly variation and eliminates the adhesive application step.
After assembly, products must pass immersion testing at a depth of 1 m for 30 minutes per IP67, combined with air leak testing to detect defects early on the line. For headlamps, a breather membrane should also be added to equalize pressure and prevent moisture from being drawn in as temperatures change.
Converting to drawing
AMS supplies EPDM foam in rolls and offers die-cutting to drawing, with a pre-applied adhesive suited to the lamp or sensor housing material.
One often-overlooked point is the gasket contact surface. PC or PP lamp housings may have parting lines or small flash that create leak paths. The surface should be designed to be flat, wide enough and with a locating groove so the gasket does not shift when the housing is closed. For adhesive-backed EPDM foam, check the adhesion of the adhesive layer on the housing material after damp heat testing, because a partially detached gasket will also lose its seal.
For radar sensors, also ensure that the gasket material contains no conductive fillers that could interfere with the signal.
To receive EPDM gasket samples for lamp and sensor assemblies, please contact AMS Vietnam.
