Quick answer: CNC Machining Fused Silica covers Fused Silica (CTE 0.55 x 10^-6 /K, 185 nm – 2.5 um); CNC Machining to +/-0.01 mm positional. Prototypes ship in 5-10 working days.
We machine Fused Silica daily, in thicknesses from 0.5 – 50 mm. The controlling numbers: +/-0.01 mm positional working tolerance, 0.4 mm slot width minimum features, and Ra 0.4 um ground, optional polish 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 | CNC Machining |
| Working tolerance | +/-0.01 mm positional |
| Minimum feature | 0.4 mm slot width |
| Surface finish | Ra 0.4 um ground, optional polish |
| Thickness window | 0.5 – 50 mm |
| Edge condition | chamfered 0.1 – 0.5 mm as standard |
| RFQ inputs | PDF/DXF/STEP drawing, quantity brackets, surface and edge spec |
Process window
CNC Machining earns its place through complex 3D geometry – pockets, steps, counterbores and compound edges in one setup. Its boundary condition – internal corners carry a minimum radius equal to the smallest practical tool, typically R0.5 mm – is the first thing our DFM review checks.
Beyond this page, Fused Silica routinely runs through drilling, laser cutting, lapping, ultrasonic machining in our shop – most real parts combine two or three of these steps.
Specification advice
Before sending the RFQ, check these against your drawing:
- Material note: its hardness and brittleness demand diamond tooling and controlled feeds.
- Process boundary: internal corners carry a minimum radius equal to the smallest practical tool, typically R0.5 mm.
- 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.
Typical applications
Orders for cnc machining fused silica cluster in laser systems (windows, beam splitters, debris shields); medical diagnostics (flow cells, slides, microplate bottoms, cuvette windows); microfluidic devices (chips, manifolds, via plates, bonded stacks). Background reading on the underlying material science: RP Photonics: fused silica.
Dimensions still moving? Configure this part live in the 3D builder below, or open the full custom glass machining 3D builder to start from a blank canvas.
Useful companion pages: CNC machining capability, material selection guide, custom microfluidic chip.
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 cnc machining hold?
+/-0.01 mm positional with minimum features of 0.4 mm slot width. Internal corners carry a minimum radius equal to the smallest practical tool, typically R0.5 mm.
What equipment runs the cnc machining work?
4-axis machining centers with diamond tooling and through-spindle coolant.
Specifications on this page were last reviewed by our engineering team in July 2026.