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Custom Silicone O-Rings

Standard and custom silicone O-rings molded to tight tolerances — for fluid, air and dust sealing in industrial, automotive, food and medical applications.

Sealing Rings

O-Rings Engineered to Your Spec

An O-ring's seal depends on three things: the right cross-section, the right compression, and the right hardness for your gland and pressure. We help you get all three right, from standard dash sizes to fully custom geometry.

  • Standard dash sizes — AS568 reference diameters
  • Custom IDs & cross-sections — from your 2D or 3D drawing
  • Multi-cavity tooling — for cost-effective high volume
  • Food & medical grades — FDA / LFGB compliant
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Silicone O-rings and sealing rings in black and blue, produced in the CYES SILICONE molding workshop
Material & Performance

Choosing the Right O-Ring Material

Match the compound to your fluid, temperature and pressure environment.

RequirementRecommended gradeTypical hardness
Food & beverage contactFood-grade silicone (FDA / LFGB)50 – 60A
Medical / pharmaceuticalMedical-grade platinum-cured silicone40 – 50A
Industrial & hydraulicSolid silicone rubber (RoHS / REACH)60 – 70A
Fuel & solvent exposureFluorosilicone (FVMQ)60 – 75A

Compression Set

Low-compression-set compounds keep the O-ring's rebound over repeated cycles.

Temperature Range

Rated from -40 °C to +230 °C depending on the compound selected.

Precision Fit

Mold cavities machined to ±0.01 mm, with finished-part tolerance confirmed during DFM.

Common Questions

Silicone O-Ring FAQ

Both. We mold standard dash-size O-rings and fully custom inner diameter, cross-section and cord-diameter O-rings from your drawing or sample. For high-volume standard sizes, multi-cavity tooling keeps unit cost low.
Our mold cavities are machined to ±0.01 mm. Because silicone is flexible, finished O-ring dimensions typically hold ±0.1–0.3 mm depending on size. We confirm the exact tolerance plan during DFM review.
Most O-ring seals use Shore 50A–70A. Softer grades (50A) seal better on uneven or low-clamping-force surfaces, while firmer grades (70A) resist extrusion at higher pressure. Our engineers recommend a hardness for your pressure and gland design.
Yes. We offer food-contact and medical-grade platinum-cured silicone compounds tested for FDA 21 CFR, LFGB, RoHS and REACH compliance as required by your market and application.

Need Silicone O-Rings?

Send your drawing, sample or dimensions. We will review material, hardness and tolerance before quoting.

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