Electromagnetic interference (EMI) can disrupt signal integrity or completeness, degrade sensor and system performance, and compromise regulatory compliance in sensitive electronic assemblies. Industries such as aerospace, defense, medical devices, telecommunications, and industrial electronics rely on effective EMI shielding and environmental sealing to protect equipment in a variety of operational conditions.
Robert McKeown Company is a fabricator specializing in custom EMI shielding solutions, including spliced and vulcanized EMI O-rings, for OEM and MRO applications. With more than 85 years of engineering and fabrication experience, our team supports customers through precision converting, rapid prototyping, and material-driven application engineering services.
Learn more about vulcanized EMI O-rings, sealing solutions for harsh environments, and custom material and sizing options for EMI shielding applications.
Advantages of Vulcanized EMI O-Rings Over Molded Alternatives
Spliced and vulcanized EMI O-rings are made from extruded stock, cut to length, and vulcanized at the ends to form a continuous, closed-loop seal through a controlled heat-and-pressure bonding process. This method eliminates non-conductive adhesives and minimizes discontinuities that can disrupt electrical continuity or weaken mechanical performance. The resulting joint typically matches or exceeds the tensile strength of the base elastomer, for uniform compression and consistent EMI shielding throughout service life.
From a manufacturing perspective, vulcanization supports large diameter assemblies, custom cross-sections, and non-standard geometries without the tooling investment required for molding. This often streamlines the interactive design process and reduces lead times, especially for low-to-medium production volumes. Vulcanized designs are commonly specified for aerospace enclosures, military electronics, medical instrumentation, telecom equipment, and RF test chambers, where dimensional precision and shielding consistency are tightly controlled.
High-Performance EMI O-Rings for Harsh Environments
Electronic enclosures used in military, aerospace, oil and gas, telecommunications, and industrial automation environments are commonly subject to any number or combination of extreme temperatures, chemical exposure, vibration, moisture, and mechanical stressors. The EMI O-rings in these systems, therefore, must maintain both electrical conductivity and environmental sealing without degradation or failure over extended service cycles.
High-performance EMI O-rings are made with conductive elastomer formulations filled with metallic particles such as silver, nickel, or aluminum. These fillers sustain conductivity while also preserving elastic recovery and compression stability. The materials are also developed to resist corrosion, thermal cycling, chemical attack, and pressure-induced damage, which means they are an excellent choice for reliable shielding performance in sealed electronic housings, shielded connectors, RF test chambers, and communication systems.
Material Options for Vulcanized EMI O-Rings
Different O-ring materials have different physical and chemical properties, so it’s critical to choose materials that are suited to the specific application. In general, these elastomer bases are combined with conductive fillers to meet electrical and environmental performance targets. Common options include:
- Silicone: Suitable for wide temperature ranges; exhibits low compression set and stable mechanical performance in aerospace, military, and sensitive electronics applications.
- Fluorosilicone: Similar properties as silicone properties with added resistance to fuels, oils, and hydraulic fluids; well-suited to defense, aviation, and industrial environments involving chemical exposure.
- FKM and specialty elastomers: Enhanced thermal stability and chemical resistance for aggressive service conditions and elevated operating temperatures.
Adjusting the elastomer base, conductive filler type, and vulcanization parameters allows engineers to tailor an O-ring for specific electrical, sealing, and mechanical requirements.
Custom EMI O-Ring Sizing and Fabrication Standards
At Robert McKeown, we fabricate custom spliced and vulcanized O-rings from a variety of materials to meet precise dimensional, electrical, and sealing specifications. Our capabilities include MIL-DTL-83528 and M83528 slash-size configurations, and we are ISO 9001-certified for quality management.
Contact us to learn more about our material selection and manufacturing capabilities, or request a quote to start your next EMI shielding project.