EngineerBenchChecking O-ring squeeze and gland fill
O-ring squeeze compares the installed cross-section with the available gland depth. Gland fill compares the ring's cross-sectional area with the groove area. These are different checks: a ring can have the intended squeeze while leaving too little space in the groove for swelling or dimensional variation.
Use the installed dimensions
Stretch changes the cross-section in this simplified constant-volume model. Enter free cross-section, stretch, groove width, and depth consistently rather than mixing free and installed measurements. The swelling allowance increases the modeled occupied area; it does not select a compatible elastomer.
Geometry does not establish sealing performance
Pressure, extrusion clearance, temperature, fluid compatibility, surface finish, and motion affect seal selection. This tool does not determine a suitable compound or certify a gland design. Check tolerances and the seal supplier's guidance for the actual static or dynamic application.
Comparing compression and occupied space
If an installed O-ring cross-section is 3 mm and gland depth is 2.4 mm, geometric squeeze is 20 percent. That percentage compares the compression with the installed section, not with groove width. Gland fill instead compares occupied cross-sectional area with the available groove area. Increasing groove width can reduce fill without changing depth-based squeeze.
The stretch adjustment assumes an approximate constant material volume and a uniform installed section. It does not account for every molded tolerance, local deformation, or compound behavior. Evaluate dimensional extremes as well as nominal geometry: a larger ring section and smaller groove can increase both squeeze and fill. Swelling allowances should be based on the actual fluid, compound, temperature, and exposure, not selected only to make the calculation pass. The result is useful for identifying geometric conflicts before consulting a seal supplier. It does not set permissible extrusion clearance, pressure capability, friction, or the surface requirements needed for a reliable seal.
Formula
Installed section ≈ free section / √stretch ratio. Squeeze = (installed section − depth)/installed section.