Cover glass mechanical and reloiability test
Jun 13, 2026
The test are cover glass proves its actual toughness. Most of them are destructive or designed to mimic longterm use.
Surface stress: It measures both the depth of compressive stress layer and the overall stress value after chemical strengthened. It's the single most important indicator of how good performance the strengthening process. The Chinese national standars require chemically strengthened cover glass to have a surface stress value 400MPa above.
Impact resistance: It simulates what will happe when a drop. A 227g steel ball is dropped from different heights depending on the glass thickness, and you check whether the glass holds up.
Scratch resistance – A direct measure of surface hardness. This is done using either a pencil of a specified hardness or a diamond stylus, following the method laid out in GB/T 39815-2021.
Chemical resistance – For automotive cover glass in particular, you need to test how well it handles things like sunscreen, cleaning agents, and sweat. There's a draft standard, ISO 25774, that focuses specifically on the chemical resistance and easy-clean performance of anti-fingerprint coatings.
Ink adhesion – A cross-cut test, where you apply tape over a scored grid pattern and then peel it off to see how much ink, if any, comes with it.
Environmental reliability – This covers high-temperature and high-humidity exposure, thermal cycling, salt spray, and similar conditions. The goal is simple: make sure the glass stays stable when the environment isn't.
