Double-Side Polishing Borofloat 33: Borofloat 33 (CTE 3.25 x 10^-6 /K, 350 nm – 2.0 um); Double-Side Polishing to TTV under 3 um. Single-piece prototypes to production volumes, quoted from your drawing.
Ask any process engineer what makes borofloat 33 difficult and the answer is specific: float tin side must be tracked when parts see coating or bonding steps. Our double-side polishing line is tooled around exactly that – planetary double-side polishers with carrier plates – holding TTV under 3 um on parts from 0.1 – 10 mm thick.
Specification envelope
| 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 | Double-Side Polishing |
| Working tolerance | TTV under 3 um |
| Minimum feature | Ra below 0.5 nm both faces |
| Surface finish | 60/40 to 20/10 both faces |
| Thickness window | 0.1 – 10 mm |
| Edge condition | edge-rounded before DSP |
| RFQ inputs | PDF/DXF/STEP drawing, quantity brackets, surface and edge spec |
Manufacturing capability
The core strength of Double-Side Polishing is wafer-grade parallelism and sub-nanometer roughness on both faces simultaneously. The honest limit: parts must be round or near-round; strongly asymmetric outlines wedge in the carriers. Both belong on the drawing before quoting, not after.
One material, many routes: on Borofloat 33 we also quote edge grinding, grinding, cnc machining, ultrasonic machining, and multi-step drawings are the norm rather than the exception.
Specification advice
Before sending the RFQ, check these against your drawing:
- Material note: float tin side must be tracked when parts see coating or bonding steps.
- Process boundary: parts must be round or near-round; strongly asymmetric outlines wedge in the carriers.
- 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 double-side polishing borofloat 33 cluster in led packaging (groove covers, phosphor carriers, package windows); machine vision (camera windows, ring-light diffusers, calibration plates); microfluidic devices (chips, manifolds, via plates, bonded stacks). 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 Borofloat 33 selection guide, 4 inch Borofloat wafers, glass hole micromachining.
Common 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 double-side polishing hold?
TTV under 3 um with minimum features of Ra below 0.5 nm both faces. Parts must be round or near-round; strongly asymmetric outlines wedge in the carriers.
What equipment runs the double-side polishing work?
Planetary double-side polishers with carrier plates.
Specifications on this page were last reviewed by our engineering team in July 2026.