The O-ring cords series is not here to outshine molded O-rings; it’s here to keep your operation moving when time and geometry push back. Think of a continuous, round-profile elastomer you cut to length and join—an O‑ring made on site, at the diameter you need, when you need it. Used wisely, cords bridge the gap between downtime and a properly sourced molded ring.
When o ring cords make sense—and when they don’t
· Access constraints: The seal path won’t accept a closed ring. A cord can be laid into the groove and joined in place, avoiding teardown.
· Immediate uptime: No stock on the exact AS568 size, but production must resume. A cut‑and‑bond cord restores function fast.
· Not for pressure/dynamics: Adhesive or even vulcanized joints are the weak link. Use them primarily for static, non‑pressurized duties; for pressure, pulsation, or motion, revert to molded endless O‑rings or consider an x ring at the design stage for better anti‑twist and lower breakaway.
Materials choose
· NBR (nitrile): Workhorse for lubricating and hydraulic oils; economical; avoid continuous service above about +125°C; less tolerant to UV and aging outdoors.
· FKM: Suited for elevated temperatures up to about +250°C and many strong acids/bases; not recommended for hot water or steam; flexibility falls near −20°C and below.
Selection is a four‑factor check: medium, temperature profile (peak/continuous), pressure exposure, and uptime target. In regulated environments (food, pharma) or aggressive solvents, match compound approvals and compatibility. Typical durometers range 70–90 Shore A; higher hardness resists extrusion and pressure, lower hardness helps low‑temperature assembly.
Joining details that actually matter
· Cut and bond quality: Square or 45° scarf cuts both work if executed cleanly. Thin, uniform adhesive layers and proper cure time beat “more glue” every day.
· Alignment and stress transfer: Heat‑vulcanized joints or precision sleeves improve concentricity and reduce stress concentrations—useful in tight‑tolerance static interfaces.
· Groove fundamentals: Cords inherit O‑ring groove rules. Squeeze, chamfers, and finish drive contact stress and leakage. The joint simply adds a variable you must respect.
· Treat the seam as the life limiter: thermal cycling, chemical swell, and micro‑movement stack up there first. Plan inspection intervals accordingly.
Where o ring cords deliver value
· Static flanges and covers: Pumps, hydraulic manifolds, gear housings, engine covers, reducers, and access ports.
· Large diameters and custom lengths: Water treatment basins, chemical process vessels, wind and metallurgy equipment inspection windows.
· Service-friendly enclosures: Robotics control boxes, industrial
electronics, and appliances with non‑pressurized seals.
· Conversely, primary aerospace, rail propulsion, and defense criticals typically specify molded rings or specialized seals. Use cords there only for non‑critical static roles or temporary fixes.
Sizing, tolerances, and practical picks
· Cross‑section: Larger sections handle wear, gap, and form deviations better, but demand tighter groove control and careful assembly.
· Precision cords: For leakage‑sensitive static interfaces, DEDE precision cords with controlled tolerances reduce seam runout and mismatch.
· Maintenance math: Record seam placement, adhesive type, cure time, and the environmental profile. Expect the joint to set service life—schedule replacements before it does.
DEDE brand, services, and how to engage
· Portfolio and pricing: The DEDE O-ring cords series spans mainstream materials and cross‑sections, with precision options. Prices appear on product pages; if none is listed, contact us online or leave a message for a quote and lead time.
· Fast stock, full custom: Ready‑to‑ship standard parts—O‑rings, oil seals, and cords—across thousands of sizes for urgent needs. For non‑standard cases, we provide end‑to‑end support: material selection, groove/structure design, prototyping, and testing.
· Experience and capability: Over 30 years focused on sealing lets us help reduce friction and wear, extend service intervals, and improve reliability. With in‑house manufacturing and testing, deliveries are predictable; products serve customers in 80+ countries. We operate as a provincial technology innovation center and hold specialized‑and‑innovative and high‑tech recognitions within our industrial cluster.
If you need a seal right now and a closed ring won’t fit or isn’t in stock,
cords are the agile choice. If the interface carries pressure or moves, molded
rings—or, for low‑friction dynamics, an x ring—belong in your design. Share your
medium, temperature, pressure, and uptime targets; we’ll help you pick the most
appropriate path with the fewest trade‑offs.
