Quick answer: Lapping Borofloat 33 covers Borofloat 33 (CTE 3.25 x 10^-6 /K, 350 nm – 2.0 um); Lapping to flatness 1 – 3 um. Prototypes ship in 5-10 working days.
We lap Borofloat 33 daily, in thicknesses from 0.2 – 40 mm. The controlling numbers: flatness 1 – 3 um working tolerance, thickness +/-0.003 mm minimum features, and Ra 0.2 – 0.6 um matte off the machine. Where the drawing asks for more, downstream lapping and polishing take over.
Specifications at a glance
| 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 | Lapping |
| Working tolerance | flatness 1 – 3 um |
| Minimum feature | thickness +/-0.003 mm |
| Surface finish | Ra 0.2 – 0.6 um matte |
| Thickness window | 0.2 – 40 mm |
| Edge condition | not applicable |
| RFQ inputs | PDF/DXF/STEP drawing, quantity brackets, surface and edge spec |
Capabilities and limits
The core strength of Lapping is restoring flatness and parallelism on plates and repairing bowed stock. The honest limit: lapped faces are translucent-matte; optical clarity requires a subsequent polish. Both belong on the drawing before quoting, not after.
One material, many routes: on Borofloat 33 we also quote drilling, etching, cnc machining, polishing, and multi-step drawings are the norm rather than the exception.
DFM notes from the shop floor
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: lapped faces are translucent-matte; optical clarity requires a subsequent polish.
- 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.
Who orders this
lapping borofloat 33 shows up across led packaging (groove covers, phosphor carriers, package windows); mems devices (cap wafers, TGV substrates, motion-sensor lids); 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 builder below, draw a dimensioned 2D drawing from it, or open the site-wide custom glass machining 3D + 2D builder for fully custom parts.
Related reading on this site: Borofloat 33 selection guide, 4 inch Borofloat wafers, glass hole micromachining.
Common questions
What equipment runs the lapping work?
Cast-iron lap plates with boron carbide and alumina slurries.
Is there a minimum order for lapping borofloat 33?
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.
Specifications on this page were last reviewed by our engineering team in September 2026.