O-Ring Groove Design

Proper O-ring groove design is critical to ensure reliable sealing performance and long service life. Incorrect gland dimensions can lead to extrusion, leakage, or premature failure.

What Is an O-Ring Groove (Gland)?

An O-ring groove, also known as a gland, is the machined recess that houses the O-ring. The groove controls O-ring compression, stretch, and volume fill under operating conditions.

Key Factors in O-Ring Groove Design

• O-ring cross-section diameter
• Groove width and depth
• Compression (squeeze)
• Stretch and clearance gap
• Operating pressure and temperature

Recommended O-Ring Compression

Application Type	Recommended Compression
Static Face Seal	20% – 30%
Static Radial Seal	15% – 25%
Dynamic Seal	8% – 16%

Groove Width and Volume Fill

The groove width must allow the O-ring to deform without overfilling. Excessive volume fill can cause extrusion and seal damage.

• Recommended volume fill: 70% – 85%
• Thermal expansion must be considered
• FKM requires more expansion allowance than NBR

Static vs Dynamic Groove Design

Groove dimensions differ depending on whether the O-ring is used in static or dynamic applications.

Design Factor	Static Seal	Dynamic Seal
Compression	Higher	Lower
Surface Finish	Standard	Fine (≤ Ra 0.4 µm)
Lubrication	Optional	Recommended

Surface Finish and Tolerances

Surface finish of the groove directly impacts sealing effectiveness and wear resistance.

• Static sealing: Ra 1.6 µm or smoother
• Dynamic sealing: Ra 0.2 – 0.4 µm
• Avoid sharp edges and burrs

Common O-Ring Groove Design Mistakes

• Over-compression causing accelerated wear
• Insufficient groove width
• Ignoring pressure-induced extrusion
• Incorrect material selection

O-Ring Groove Design Standards

Common standards used for O-ring groove design include:

• AS568 (inch sizes)
• ISO 3601
• DIN 3771

Need Help with O-Ring Groove Design?

Our engineers can assist with groove dimension calculations, material selection, and pressure optimization for your sealing application.