O-RING & GASKET SEAL DESIGN

Elastomer seals rely on compression (squeeze) of the cross-section to fill machining marks and resist pressure. Typical squeeze is 15-30% of free cross-section diameter, lower for dynamic seals to limit friction, higher for static. Groove fill should be 60-85% to allow for elastomer swell and thermal expansion. Extrusion gap (clearance between the two sealed surfaces) must stay below the limit set by elastomer hardness and pressure differential, otherwise the seal extrudes into the gap and fails.

• Squeeze % = (CS_free - CS_compressed) / CS_free × 100
• Gland fill % = (CS_area) / (groove area) × 100
• Friction F = f_c · π · D · CS
• Max gap = f(durometer, ΔP) per Parker/Apple Rubber chart

References & StandardsAS568, ISO 3601, Parker O-Ring Handbook ORD 5700

Use this module for any static or dynamic O-ring, X-ring, or square-cut seal: hydraulic cylinders, pneumatic actuators, pressure-vessel flanges, vacuum chambers. Pick the cord diameter from a standard size table (AS568 for inch, ISO 3601 for metric), set squeeze and gland fill, and verify extrusion gap. For elevated pressure, add an anti-extrusion backup ring or use a harder durometer.