Quick answer: Ultrasonic Machining Borofloat 33 covers Borofloat 33 (CTE 3.25 x 10^-6 /K, 350 nm – 2.0 um); Ultrasonic Machining to +/-0.02 mm form. Prototypes ship in 5-10 working days.
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 ultrasonic machining line is tooled around exactly that – 20 kHz ultrasonic spindles with shaped diamond form tools – holding +/-0.02 mm form on parts from 0.5 – 25 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 | Ultrasonic Machining |
| Working tolerance | +/-0.02 mm form |
| Minimum feature | 0.3 mm blind features |
| Surface finish | matte machined surface |
| Thickness window | 0.5 – 25 mm |
| Edge condition | crack-free feature edges |
| RFQ inputs | PDF/DXF/STEP drawing, quantity brackets, surface and edge spec |
Manufacturing capability
The core strength of Ultrasonic Machining is blind cavities, non-round holes and stepped profiles that rotary tools cannot reach. The honest limit: material removal is slow, so it is reserved for features other processes cannot form. Both belong on the drawing before quoting, not after.
One material, many routes: on Borofloat 33 we also quote edge grinding, drilling, lapping, grinding, and multi-step drawings are the norm rather than the exception.
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.
- Process boundary: material removal is slow, so it is reserved for features other processes cannot form.
- 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.
Who orders this
ultrasonic machining borofloat 33 shows up across 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.
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.
Related reading on this site: Borofloat 33 selection guide, 4 inch Borofloat wafers, fused silica wafers 2-12 inch.
Buyer questions, answered
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 ultrasonic machining hold?
+/-0.02 mm form with minimum features of 0.3 mm blind features. Material removal is slow, so it is reserved for features other processes cannot form.
Specifications on this page were last reviewed by our engineering team in July 2026.