Ultrasonic Machining Optical Glass – Optical Glass (CTE 7.1 x 10^-6 /K, 350 nm – 2.0 um); Ultrasonic Machining to +/-0.02 mm form. No minimum order; DFM review included with every RFQ.
We ultrasonically machine Optical Glass daily, in thicknesses from 0.5 – 25 mm. The controlling numbers: +/-0.02 mm form working tolerance, 0.3 mm blind features minimum features, and matte machined surface 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 | Ultrasonic Machining |
| Working tolerance | +/-0.02 mm form |
| Minimum feature | 0.3 mm blind features |
| Surface finish | matte machined surface |
| Thickness window | 0.5 – 25 mm |
| Edge condition | crack-free feature edges |
| RFQ inputs | PDF/DXF/STEP drawing, quantity brackets, surface and edge spec |
Process window
Ultrasonic Machining earns its place through blind cavities, non-round holes and stepped profiles that rotary tools cannot reach. Its boundary condition – material removal is slow, so it is reserved for features other processes cannot form – is the first thing our DFM review checks.
Beyond this page, Optical Glass routinely runs through dicing, double-side polishing, drilling, grinding in our shop – most real parts combine two or three of these steps.
Getting the drawing right
Three items decide most of the cost and lead time on this work:
- Material note: index-certified blanks must be oriented and serialized through the shop to keep melt traceability.
- Process boundary: material removal is slow, so it is reserved for features other processes cannot form.
- 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
ultrasonic machining optical glass shows up across ccd inspection equipment (CCD cover plates, reference grids, stage glass); machine vision (camera windows, ring-light diffusers, calibration plates); scientific instruments (reference flats, cells, prism mounts, stage inserts). 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.
Engineers scoping this work usually also review AR optical windows, AR coated glass materials, high-purity quartz guide.
Buyer questions, answered
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 ultrasonic machining hold?
+/-0.02 mm form with minimum features of 0.3 mm blind features. Material removal is slow, so it is reserved for features other processes cannot form.
What equipment runs the ultrasonic machining work?
20 kHz ultrasonic spindles with shaped diamond form tools.
Specifications on this page were last reviewed by our engineering team in July 2026.