Quick answer: Thermal Tempering Borosilicate Glass covers Borosilicate Glass (CTE 3.3 x 10^-6 /K, 360 nm – 2.0 um); surface compression > 69 MPa per ASTM C1048. Prototypes ship in 5-10 working days.
Specify thermal tempering borosilicate glass when the bare substrate falls short: full thermal temper, processed by furnace + air quench, >3 mm parts, brings Borosilicate Glass to surface compression > 69 MPa per ASTM C1048.
Specification envelope
| Material | Borosilicate Glass (3.3 expansion group per ISO 3585) |
|---|---|
| Thermal expansion (CTE) | 3.3 x 10^-6 /K |
| Service temperature | 450 C continuous |
| Transmission range | 360 nm – 2.0 um |
| Density | 2.23 g/cm3 |
| Knoop hardness | 480 kg/mm2 |
| Refractive index | 1.473 @ 587 nm |
| Stock thickness | 0.50 – 30 mm |
| Maximum blank size | 600 x 400 mm |
| Treatment | Thermal Tempering – full thermal temper |
| Specification | surface compression > 69 MPa per ASTM C1048 |
| Deposition / method | furnace + air quench, >3 mm parts |
| RFQ inputs | PDF/DXF/STEP drawing, quantity brackets, surface and edge spec |
Capabilities and limits
One material, many routes: on Borosilicate Glass we also quote lapping, drilling, coring, cnc machining, 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: sheet stock carries more thickness variation than float wafer stock, so lapping is often the first step.
- Sequence matters: all machining happens before thermal tempering; post-coating rework is not economical.
- 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
Orders for thermal tempering borosilicate glass cluster in medical diagnostics (flow cells, slides, microplate bottoms, cuvette windows); scientific instruments (reference flats, cells, prism mounts, stage inserts); laboratory instruments (cuvettes, sight glasses, stir-cell windows). Background reading on the underlying material science: ISO 3585 borosilicate glass 3.3.
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: glass sandblasting, material selection guide, ultra-thin quartz discs.
Common questions
Is there a minimum order for thermal tempering borosilicate glass?
No. Single prototypes are accepted, and pricing steps down at 10, 100 and 1,000 pieces.
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 Borosilicate Glass parts?
Ground features hold +/-0.01 mm and lapped thickness reaches +/-0.003 mm. Sheet stock carries more thickness variation than float wafer stock, so lapping is often the first step.
Specifications on this page were last reviewed by our engineering team in September 2026.