Quick answer: Grinding Fused Silica covers Fused Silica (CTE 0.55 x 10^-6 /K, 185 nm – 2.5 um); Grinding to flatness to 5 um over 100 mm. Prototypes ship in 5-10 working days.
We grind Fused Silica 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 | Fused Silica (JGS1 (UV), JGS2 (standard), JGS3 (IR)) |
|---|---|
| Thermal expansion (CTE) | 0.55 x 10^-6 /K |
| Service temperature | 1,100 C continuous |
| Transmission range | 185 nm – 2.5 um |
| Density | 2.20 g/cm3 |
| Knoop hardness | 500 kg/mm2 |
| Refractive index | 1.458 @ 587 nm |
| Stock thickness | 0.10 – 50 mm |
| Maximum blank size | 450 x 450 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, Fused Silica routinely runs through polishing, laser cutting, lapping, ultrasonic machining in our shop – most real parts combine two or three of these steps.
Specification advice
The shop-floor rules that matter here:
- Material note: its hardness and brittleness demand diamond tooling and controlled feeds.
- 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.
Where these parts end up
The recurring buyers of grinding fused silica: scientific instruments (reference flats, cells, prism mounts, stage inserts); machine vision (camera windows, ring-light diffusers, calibration plates); ccd inspection equipment (CCD cover plates, reference grids, stage glass). Background reading on the underlying material science: RP Photonics: fused silica.
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: edge grinding overview, fused silica material guide, alkali-free display glass.
Buyer questions, answered
What tolerances are achievable on Fused Silica parts?
Ground features hold +/-0.01 mm and lapped thickness reaches +/-0.003 mm. Its hardness and brittleness demand diamond tooling and controlled feeds.
What thickness range do you stock for Fused Silica?
Standard stock spans 0.10 – 50 mm, with blanks up to 450 x 450 mm. Other formats are sourced per order.
How does Fused Silica behave under heat?
CTE is 0.55 x 10^-6 /K and continuous service reaches 1,100 C continuous, which is what drives its use where near-zero thermal expansion 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.