Quick answer: Borofloat 33 Square Glass Windows covers Borofloat 33 (CTE 3.25 x 10^-6 /K, 350 nm – 2.0 um); 5 x 5 mm to 300 x 300 mm, thickness 0.3 – 25 mm. Prototypes ship in 5-10 working days.
We build borofloat 33 square glass windows to print – 5 x 5 mm to 300 x 300 mm, thickness 0.3 – 25 mm – primarily in Borofloat 33. Typical use: instrument viewports and detector covers.
Key parameters
| Material | Borofloat 33 (SCHOTT float production, wafer grade) |
|---|---|
| Thermal expansion (CTE) | 3.25 x 10^-6 /K |
| Service temperature | 450 C continuous |
| Transmission range | 350 nm – 2.0 um |
| Density | 2.23 g/cm3 |
| Knoop hardness | 480 kg/mm2 |
| Refractive index | 1.471 @ 587 nm |
| Stock thickness | 0.70 – 25.4 mm |
| Maximum blank size | 500 x 500 mm |
| Geometry | Square Glass Windows |
| Size envelope | 5 x 5 mm to 300 x 300 mm, thickness 0.3 – 25 mm |
| Key tolerance | side +/-0.03 mm |
| RFQ inputs | PDF/DXF/STEP drawing, quantity brackets, surface and edge spec |
Specification advice
Three items decide most of the cost and lead time on this work:
- Material note: float tin side must be tracked when parts see coating or bonding steps.
- Hold the controlling dimension (side +/-0.03 mm) and let secondary dimensions carry standard tolerance – it is the single biggest cost lever.
- 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.
What the process holds
Beyond this page, Borofloat 33 routinely runs through laser cutting, edge grinding, double-side polishing, dicing in our shop – most real parts combine two or three of these steps.
Production route: cnc machining, polishing, edge grinding – selected per geometry and volume. Edge condition: chamfered 0.1 – 0.5 mm as standard.
Who orders this
The recurring buyers of borofloat 33 square glass windows: optical sensors (sensor windows, filter caps, lens covers); mems devices (cap wafers, TGV substrates, motion-sensor lids); led packaging (groove covers, phosphor carriers, package windows). Background reading on the underlying material science: SCHOTT BOROFLOAT product page.
The fastest route to a quote is geometry: use the 3D builder below, draw a dimensioned 2D drawing from it, or open the site-wide custom glass machining 3D + 2D builder for fully custom parts.
Engineers scoping this work usually also review Borofloat 33 selection guide, wafer dicing process, LED groove cover glass.
Frequently asked questions
Is there a minimum order for borofloat 33 square glass windows?
No. Single prototypes are accepted, and pricing steps down at 10, 100 and 1,000 pieces.
How fast can prototypes ship?
Machined prototypes ship in 5 – 10 working days. Coated or bonded parts add 1 – 2 weeks depending on queue slots.
What files do you need for a quote?
A dimensioned PDF plus DXF or STEP geometry. If only a sketch exists, our drawing review service formalizes it before quoting.
Do parts ship with inspection data?
Dimensional reports, surface certificates and material certs per melt are available; specify the level on the RFQ.
Specifications on this page were last reviewed by our engineering team in September 2026.