Edge Grinding Borofloat 33 Wafers: Borofloat 33 (CTE 3.25 x 10^-6 /K, 350 nm – 2.0 um); Edge Grinding to chamfer +/-0.05 mm. Single-piece prototypes to production volumes, quoted from your drawing.
The combination of Borofloat 33 and Edge Grinding comes up constantly in RFQs for a reason – the material offers anodic bonding to silicon, and Edge Grinding is the right way to get accurate geometry into it. Expect chamfer +/-0.05 mm and ground C or R profile, polish option.
The numbers
| 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 |
| Process | Edge Grinding |
| Working tolerance | chamfer +/-0.05 mm |
| Minimum feature | 0.1 mm chamfer leg |
| Surface finish | ground C or R profile, polish option |
| Thickness window | 0.1 – 25 mm |
| Edge condition | C-chamfer, R-round, pencil or OG profile |
| Wafer formats | 2", 3", 4", 6", 8" and 12" with SEMI flats or notch |
| TTV | under 3 – 5 um by format |
| RFQ inputs | PDF/DXF/STEP drawing, quantity brackets, surface and edge spec |
Getting the drawing right
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.
- Process boundary: profiles below 0.1 mm leg length are lapped by hand and priced per edge.
- 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
Edge Grinding earns its place through edge strength – a finished chamfer roughly doubles the bend strength of a cut edge. Its boundary condition – profiles below 0.1 mm leg length are lapped by hand and priced per edge – is the first thing our DFM review checks.
Beyond this page, Borofloat 33 routinely runs through grinding, sandblasting, etching, drilling in our shop – most real parts combine two or three of these steps.
Who orders this
The recurring buyers of edge grinding borofloat 33 wafers: microfluidic devices (chips, manifolds, via plates, bonded stacks); led packaging (groove covers, phosphor carriers, package windows); machine vision (camera windows, ring-light diffusers, calibration plates). Background reading on the underlying material science: SCHOTT BOROFLOAT product page.
Dimensions still moving? Configure this part live in the 3D + 2D builder below, or open the full custom glass machining 3D + 2D builder to start from a blank canvas.
Useful companion pages: wafer dicing process, 4 inch Borofloat wafers, glass wafer coring.
Frequently asked questions
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.
What tolerances are achievable on Borofloat 33 parts?
Ground features hold +/-0.01 mm and lapped thickness reaches +/-0.003 mm. Float tin side must be tracked when parts see coating or bonding steps.
Specifications on this page were last reviewed by our engineering team in October 2026.