Double-Side Polishing Optical Glass: Optical Glass (CTE 7.1 x 10^-6 /K, 350 nm – 2.0 um); Double-Side Polishing to TTV under 3 um. Single-piece prototypes to production volumes, quoted from your drawing.
We DSP-polish Optical Glass daily, in thicknesses from 0.1 – 10 mm. The controlling numbers: TTV under 3 um working tolerance, Ra below 0.5 nm both faces minimum features, and 60/40 to 20/10 both faces off the machine. Where the drawing asks for more, downstream lapping and polishing take over.
Specifications at a glance
| Material | Optical Glass (N-BK7, H-K9L and filter glass sets) |
|---|---|
| Thermal expansion (CTE) | 7.1 x 10^-6 /K |
| Service temperature | 400 C (Tg 557 C) |
| Transmission range | 350 nm – 2.0 um |
| Density | 2.51 g/cm3 |
| Knoop hardness | 610 kg/mm2 |
| Refractive index | 1.5168 @ 587 nm |
| Stock thickness | 0.30 – 50 mm |
| Maximum blank size | 300 mm diameter |
| Process | Double-Side Polishing |
| Working tolerance | TTV under 3 um |
| Minimum feature | Ra below 0.5 nm both faces |
| Surface finish | 60/40 to 20/10 both faces |
| Thickness window | 0.1 – 10 mm |
| Edge condition | edge-rounded before DSP |
| RFQ inputs | PDF/DXF/STEP drawing, quantity brackets, surface and edge spec |
Manufacturing capability
The core strength of Double-Side Polishing is wafer-grade parallelism and sub-nanometer roughness on both faces simultaneously. The honest limit: parts must be round or near-round; strongly asymmetric outlines wedge in the carriers. Both belong on the drawing before quoting, not after.
One material, many routes: on Optical Glass we also quote polishing, coring, lapping, laser cutting, and multi-step drawings are the norm rather than the exception.
Specification advice
Before sending the RFQ, check these against your drawing:
- Material note: index-certified blanks must be oriented and serialized through the shop to keep melt traceability.
- Process boundary: parts must be round or near-round; strongly asymmetric outlines wedge in the carriers.
- 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.
Application context
The recurring buyers of double-side polishing optical glass: ccd inspection equipment (CCD cover plates, reference grids, stage glass); laser systems (windows, beam splitters, debris shields); optical sensors (sensor windows, filter caps, lens covers). Background reading on the underlying material science: RP Photonics: optical glass.
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: optical polishing capability, optical glass options, high-purity quartz guide.
Common questions
What tolerances are achievable on Optical Glass parts?
Ground features hold +/-0.01 mm and lapped thickness reaches +/-0.003 mm. Index-certified blanks must be oriented and serialized through the shop to keep melt traceability.
What thickness range do you stock for Optical Glass?
Standard stock spans 0.30 – 50 mm, with blanks up to 300 mm diameter. Other formats are sourced per order.
How does Optical Glass behave under heat?
CTE is 7.1 x 10^-6 /K and continuous service reaches 400 C (Tg 557 C), which is what drives its use where certified refractive index and dispersion matters.
What accuracy does double-side polishing hold?
TTV under 3 um with minimum features of Ra below 0.5 nm both faces. Parts must be round or near-round; strongly asymmetric outlines wedge in the carriers.
What equipment runs the double-side polishing work?
Planetary double-side polishers with carrier plates.
Specifications on this page were last reviewed by our engineering team in July 2026.