Why is lifetime verification more important than "initial no leakage"?
Many seals behave normally when they are first assembled, but in theTemperature cycling, long-term pressure, media immersionPost-failure. The goal of lifetime validation is: early exposure to risk under controlled conditions.
Key Indicator: Compression Set
After the seal is pressurized for a long period of time, the resilience decreases, which can lead to insufficient contact stress and leakage.
- The greater the compression set, the higher the long-term sealing risk is usually
- However, it needs to be judged in conjunction with the operating conditions, compression and structure.
Common Life Verification Programs (select on demand)
1) Thermal aging
Purpose: To evaluate hardening, cracking, and resilience changes at elevated temperatures.
- Suitable for: high temperature cabin, outdoor sun exposure and other scenes
2) Compression permanent deformation test
Purpose: To assess the retention of rebound after long-term compression.
- Application: Long-term static sealing (housing seals, gaskets, etc.)
3) Temperature cycling (hot and cold cycles)
Purpose: To simulate the effects of thermal expansion and contraction and stress relaxation on seals.
- Suitable for: large temperature differences in the environment, frequent hot and cold switching of equipment
4) Resistant to medium immersion
Purpose: To assess volume changes, hardness changes, and surface deterioration.
- Suitable for: contact with oils, fuels, detergents, chemical media
5) Seal retention test
Purpose: To verify that no leakage is maintained under certain pressure/water column/airtight conditions.
- Suitable for: products with defined waterproof rating or airtightness requirements
Verification should clearly state the "conditions": temperature, time, pressure/medium, number of samples, and judgment criteria. Otherwise the test results are not reproducible.
How to Write Validation as an "Executable" Requirement
You can describe it like this:
- Operating conditions: temperature range, media, pressure/waterproofing objectives
- Structural conditions: compression, clearance, assembly method
- Verification items: heat aging/compression set/temperature cycling/immersion
- Judgment: Appearance change, size change, sealing test pass or fail
Common Failure Causes and Directions for Improvement
- Excessive compression: reduced life → optimize grooves or hardness
- Media incompatibility: swelling/stiffening → re-select material
- Gap extrusion: Failure after high pressure → Gap control or reinforced support