Glass that has been tempered or heat strengthened cannot be machined. Any fabrication done prior to the heat or tempering process must be smooth as well as chip and crack free. Any holes, notches, etc. should be located on the fabricated glass part so as to avoid breakage during the strengthening process.
Chemical Strengthening
Unlike heat toughened glass, chemically strengthened soda lime glass may be cut after strengthening, but loses its added strength within the region of approximately 20 mm of the cut. Similarly, when the surface of chemically strengthened glass is deeply scratched, this area loses its additional strength.
High Ion-Exchange (HIE™) Chemically Strengthened Thin Glass CAN NOT be post fabricated. That includes:
- Asahi Dragontrail™
- Corning® Gorilla® Glass
- SCHOTT Xensation®
This glass can only be strengthened as a final step. It may be coated and screen printed, but not machined for the following reasons:
- Strengthened glass loses over 50% of its strength if successfully cut, so it would no longer be considered HIE™ chemically strengthened glass.
- HIE™ glass is under high levels of compressive stress making it extraordinarily difficult to machine.