Quick answer: Coring Borofloat 33 covers Borofloat 33 (CTE 3.25 x 10^-6 /K, 350 nm – 2.0 um); Coring to diameter +/-0.05 mm. Prototypes ship in 5-10 working days.
coring borofloat 33 is a materials problem before it is a machining problem. Borofloat 33 has float-glass flatness off the line and a Knoop hardness of 480 kg/mm2, so the coring recipe – feeds, coolant, tooling – differs from what works on ordinary float glass. The line runs diamond core drills with rotary fixtures and holds diameter +/-0.05 mm.
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 |
| Process | Coring |
| Working tolerance | diameter +/-0.05 mm |
| Minimum feature | 2 mm core diameter |
| Surface finish | ground bore, honed option |
| Thickness window | 1 – 60 mm |
| Edge condition | entry/exit chamfer standard |
| RFQ inputs | PDF/DXF/STEP drawing, quantity brackets, surface and edge spec |
DFM notes from the shop floor
The shop-floor rules that matter here:
- Material note: float tin side must be tracked when parts see coating or bonding steps.
- Process boundary: wall thickness between adjacent cores should exceed 2 mm to avoid bridge cracking.
- 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.
The full rules live in our tolerance design guide and holes and edges design guide.
Capabilities and limits
The core strength of Coring is large-diameter discs, rings and through-bores from plate stock up to 60 mm thick. The honest limit: wall thickness between adjacent cores should exceed 2 mm to avoid bridge cracking. Both belong on the drawing before quoting, not after.
One material, many routes: on Borofloat 33 we also quote drilling, dicing, laser cutting, cnc machining, and multi-step drawings are the norm rather than the exception.
Who orders this
Orders for coring borofloat 33 cluster in mems devices (cap wafers, TGV substrates, motion-sensor lids); led packaging (groove covers, phosphor carriers, package windows); optical sensors (sensor windows, filter caps, lens covers). Background reading on the underlying material science: SCHOTT BOROFLOAT product page.
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 glass wafer coring, Borofloat 33 selection guide, BF33 microfluidic chip.
Frequently asked questions
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.
What thickness range do you stock for Borofloat 33?
Standard stock spans 0.70 – 25.4 mm, with blanks up to 500 x 500 mm. Other formats are sourced per order.
How does Borofloat 33 behave under heat?
CTE is 3.25 x 10^-6 /K and continuous service reaches 450 C continuous, which is what drives its use where float-glass flatness off the line matters.
What accuracy does coring hold?
Diameter +/-0.05 mm with minimum features of 2 mm core diameter. Wall thickness between adjacent cores should exceed 2 mm to avoid bridge cracking.
Specifications on this page were last reviewed by our engineering team in July 2026.