Custom Environmental Seals, EMI Gaskets & Cushioning for ADAS Sensors & Electronics

They solve different problems and are often different parts. An environmental seal is a resilient, usually non-conductive gasket that closes a housing joint against water and dust to an ingress class under IEC 60529; it is chosen for its sealing and weather resistance. An EMI gasket is electrically conductive and maintains contact across a seam so the enclosure shields as one body, supporting the module’s emissions limits under CISPR 25; it is chosen for its conductivity.

A conductive silicone gasket can do both jobs in one part, sealing the joint and carrying the shield, which is common on a sensor-fusion ECU. The first thing to decide is whether the seam needs sealing, shielding, or both, because that sets the material.

The gasket is one element of a sealed joint, not the rating by itself. An ingress class under IEC 60529 (or the road-vehicle IP6K9K variant) is achieved by the whole joint: the groove geometry, the bolt pattern and torque, the surface finish, and the resilient gasket that closes the gap. A correctly sized closed-cell silicone gasket, compressed in a well-designed groove, lets the joint reach a high class, but the rating belongs to the tested housing.

Send the joint detail along with the target class so the gasket material, thickness and compression can be matched, and plan to verify the assembled housing against the class.

Reach for closed-cell silicone when temperature, weather or a flame rating governs. Silicone sponge holds its mechanical properties across a wider temperature span than most foams, both hot and cold, resists weather and ozone, and specific grades reach UL 94 flame ratings. That makes it the move for exterior sensors, forward modules behind glass that run hot, and any housing exposed to sun, road spray and ozone.

For a protected interior ECU at ambient temperature, a softer or lower-cost closed-cell foam may be sufficient. Confirm the grade's temperature range and any flame requirement on the data sheet.

A microporous ePTFE membrane is breathable to air but sealed to liquids, so it lets a sealed housing equalize internal pressure as temperature and altitude change. A perfectly sealed sensor housing builds and releases pressure every heat cycle, which stresses the gasket and can pump moisture past the seal or fog an optic. A small ePTFE vent patch over a port relieves that pressure and reduces condensation while keeping water and dust out, so the environmental seal lasts and the optics stay clear.

The vent does not replace the housing seal; it complements it. Send the housing volume and the temperature swing so the vent area can be sized.

Yes, conductive silicone grades are designed to do both, which is why they are common on shielded sensor and ECU enclosures. The conductive filler carries the shield across the seam while the silicone elastomer still closes the joint as an environmental gasket. The trade-off is that a conductive grade is selected and priced for its shielding, so where a seam only needs sealing, a plain environmental gasket is the simpler choice, and where a seam only needs shielding behind a separate seal, the two jobs can be split across two parts.

Define the sealing class and the shielding need together so engineering can decide whether one combined part or two parts is the better build.

Five things move a recommendation from a guess to a real direction: the job at each location (environmental sealing, EMI, venting, or cushioning), the target ingress class under IEC 60529, the operating temperature, the environment (interior, exterior, chemical), and whether the module must meet CISPR 25 emissions.

Add the joint or housing geometry or a drawing, the adhesive and liner needs, and the prototype and annual volume, and engineering can match a family, a grade direction and a converting approach, then confirm the grade-level values against the manufacturer's data sheet.

The What to send H-O box on the page lists these.

H-O is a precision converter, not a raw-material producer. We do not extrude or mold the silicone, foam or membrane; we buy sheet, slab and roll stock from the material manufacturers and convert it to your drawing, by die-cutting, kiss-cutting, laser and waterjet cutting, adhesive lamination, slitting and kitting, with material traceability and lot-level data-sheet records.

Every gasket, vent and cushion is made-to-order; we do not carry finished parts in stock and we do not advertise a no-minimum policy, though prototype quantities through full production runs are equally welcome and the minimum varies by material and part.

Prototype and production timing is summarized in the process strip near the top of the page and on the quote form.

Yes — thin sensor gaskets are commonly supplied with pressure-sensitive adhesive, kiss-cut on liner for placement into small housings. On conductive EMI gaskets the adhesive strategy matters, because a continuous insulating adhesive layer can interrupt shield continuity — options include zone-coated or conductive adhesive systems, confirmed at material review.

Camera and sensor gaskets run small, and the practical limits are set by gasket wall width and material handling rather than outside dimension alone. Very narrow walls in soft foams are the usual constraint, and kiss-cutting on liner keeps small parts manageable on the line. Send the drawing — feature sizes and wall widths are confirmed against tooling at review.

Sealing foams work within a compression window: enough deflection to follow housing tolerances and hold the seal line, but comfortably short of full densification, where the gasket stops conforming and starts loading the housing. The manufacturer’s compression-force-deflection data for the specific grade defines that window, and the housing’s closure force and tolerance stack decide where in it the design lands.

Yes — material swatches and cut samples are available on request, subject to material availability. For evaluation builds, the usual path is to send the part drawing so prototype parts are cut from the actual grade and thickness under consideration; that puts representative parts in your fixture instead of a generic swatch.

Minimums depend on the material and format rather than a single policy. Prototype quantities are quoted case-by-case, and production minimums are typically driven by the vendor’s sheet or roll purchase unit for the specific material. Stating your target annual volume on the RFQ lets H-O quote realistic break points up front.