Quick answer: CNC Machining Borofloat 33 covers Borofloat 33 (CTE 3.25 x 10^-6 /K, 350 nm – 2.0 um); CNC Machining to +/-0.01 mm positional. 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 cnc machining line is tooled around exactly that – 4-axis machining centers with diamond tooling and through-spindle coolant – holding +/-0.01 mm positional on parts from 0.5 – 50 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 | CNC Machining |
| Working tolerance | +/-0.01 mm positional |
| Minimum feature | 0.4 mm slot width |
| Surface finish | Ra 0.4 um ground, optional polish |
| Thickness window | 0.5 – 50 mm |
| Edge condition | chamfered 0.1 – 0.5 mm as standard |
| RFQ inputs | PDF/DXF/STEP drawing, quantity brackets, surface and edge spec |
Capabilities and limits
The core strength of CNC Machining is complex 3D geometry – pockets, steps, counterbores and compound edges in one setup. The honest limit: internal corners carry a minimum radius equal to the smallest practical tool, typically R0.5 mm. Both belong on the drawing before quoting, not after.
One material, many routes: on Borofloat 33 we also quote sandblasting, coring, polishing, dicing, and multi-step drawings are the norm rather than the exception.
Design guidance
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: internal corners carry a minimum radius equal to the smallest practical tool, typically R0.5 mm.
- 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.
Application context
cnc machining borofloat 33 shows up across mems devices (cap wafers, TGV substrates, motion-sensor lids); machine vision (camera windows, ring-light diffusers, calibration plates); led packaging (groove covers, phosphor carriers, package windows). Background reading on the underlying material science: SCHOTT BOROFLOAT product page.
Dimensions still moving? Configure this part live in the 3D builder below, or open the full custom glass machining 3D builder to start from a blank canvas.
For adjacent specifications, see CNC machining capability, 4 inch Borofloat wafers, Borofloat 33 selection guide.
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 cnc machining hold?
+/-0.01 mm positional with minimum features of 0.4 mm slot width. Internal corners carry a minimum radius equal to the smallest practical tool, typically R0.5 mm.
What equipment runs the cnc machining work?
4-axis machining centers with diamond tooling and through-spindle coolant.
Specifications on this page were last reviewed by our engineering team in July 2026.