Grinding Alkali-Free Glass: Alkali-Free Glass (CTE 3.2 x 10^-6 /K, 350 nm – 2.0 um); Grinding to flatness to 5 um over 100 mm. Single-piece prototypes to production volumes, quoted from your drawing.
We grind Alkali-Free Glass daily, in thicknesses from 0.3 – 60 mm. The controlling numbers: flatness to 5 um over 100 mm working tolerance, thickness to +/-0.005 mm minimum features, and Ra 0.2 – 0.8 um off the machine. Where the drawing asks for more, downstream lapping and polishing take over.
Specifications at a glance
| Material | Alkali-Free Glass (AF32 / EAGLE-class display glass) |
|---|---|
| Thermal expansion (CTE) | 3.2 x 10^-6 /K |
| Service temperature | 600 C (Tg 717 C) |
| Transmission range | 350 nm – 2.0 um |
| Density | 2.43 g/cm3 |
| Knoop hardness | 590 kg/mm2 |
| Refractive index | 1.51 @ 587 nm |
| Stock thickness | 0.10 – 1.1 mm |
| Maximum blank size | 400 x 300 mm |
| Process | Grinding |
| Working tolerance | flatness to 5 um over 100 mm |
| Minimum feature | thickness to +/-0.005 mm |
| Surface finish | Ra 0.2 – 0.8 um |
| Thickness window | 0.3 – 60 mm |
| Edge condition | ground perimeter, squareness 0.02 mm |
| RFQ inputs | PDF/DXF/STEP drawing, quantity brackets, surface and edge spec |
What the process holds
Grinding earns its place through bringing thickness, flatness and parallelism into calibrated tolerance before polish. Its boundary condition – subsurface damage of 5 – 15 um must be budgeted and removed by polishing on optical faces – is the first thing our DFM review checks.
Beyond this page, Alkali-Free Glass routinely runs through drilling, cnc machining, etching, laser cutting in our shop – most real parts combine two or three of these steps.
Specification advice
Three items decide most of the cost and lead time on this work:
- Material note: thin sheets below 0.3 mm demand carrier-supported handling through every step.
- Process boundary: subsurface damage of 5 – 15 um must be budgeted and removed by polishing on optical faces.
- Over-specification is the quiet budget killer: a 20/10 scratch-dig face costs roughly three times an 80/50 face, so grade each surface individually.
For the complete framework, see the tolerance design guide and the holes and edges design guide.
Who orders this
The recurring buyers of grinding alkali-free glass: ccd inspection equipment (CCD cover plates, reference grids, stage glass); oled packaging (cover lids, frit-seal frames, fill-port plates). Background reading on the underlying material science: SCHOTT AF 32 eco.
The fastest route to a quote is geometry: use the 3D configurator below, or the site-wide custom glass machining 3D builder for fully custom parts.
Related reading on this site: alkali-free display glass, alkali-free glass wafers, infrared windows.
Buyer questions, answered
What tolerances are achievable on Alkali-Free Glass parts?
Ground features hold +/-0.01 mm and lapped thickness reaches +/-0.003 mm. Thin sheets below 0.3 mm demand carrier-supported handling through every step.
What thickness range do you stock for Alkali-Free Glass?
Standard stock spans 0.10 – 1.1 mm, with blanks up to 400 x 300 mm. Other formats are sourced per order.
How does Alkali-Free Glass behave under heat?
CTE is 3.2 x 10^-6 /K and continuous service reaches 600 C (Tg 717 C), which is what drives its use where no alkali ion migration into TFT or sensor layers matters.
What accuracy does grinding hold?
Flatness to 5 um over 100 mm with minimum features of thickness to +/-0.005 mm. Subsurface damage of 5 – 15 um must be budgeted and removed by polishing on optical faces.
Specifications on this page were last reviewed by our engineering team in July 2026.