General Comments on Tolerancing Limits
This represents a general list of soft limits and is intended for reference only.
Reducing tolerance range increases costs.
Optimax advises a close consideration of budget (tolerance, delivery, or dollar) versus need to be made prior to choosing any value below.
Robust sensitivity analyses will help yield the most cost-effective tolerancing.
Tolerancing Limits for Aspheric Surfaces
wdt_ID | Attribute | Asphere Tolerancing Limit |
---|---|---|
1 | Glass Quality (nd, vd) | Melt Rebalanced and Controlled |
2 | Diameter (mm) | +0, -0.010 |
3 | Center Thickness (mm)⁶ | ± 0.010 |
4 | Sag – Concave (mm) | ± 0.010 |
5 | Clear Aperture | 100%⁷ |
6 | Vertex Radius⁸ | ± 0.1% or 3 HeNe fringes⁹ |
7 | Irregularity – Interferometry (HeNe fringes)¹⁰ | 0.11¹¹ |
8 | Irregularity – Profilometry (μm)¹⁰ | ± 0.5 |
9 | Wedge Lens – ETD (mm) | 0.002¹² |
10 | Bevels – Face Width @ 45° (mm)¹³ | ± 0.05 |
11 | Scratch – Dig (MIL-PRF-13830B)¹⁴ | 10 – 5 |
12 | Surface Roughness (Å RMS)¹⁵ | 10 |
- This is for the most well-behaved materials. More difficult materials (CaF2, Ohara S-FPL, etc) will need larger tolerance ranges
- Of full aperture (FA)
- In addition to irregularity
- Whichever is correspondingly larger over the clear aperture
- A vertex radius tolerance is required in addition to irregularity
- As geometry requirements move closer to a min or max shown the less likely this is possible
- This specification is extremely tight and expensive. For a more economical limit, please consider using 0.005mm.
- Subject to measurement uncertainty
- Crystals and reflective materials will receive 40W inspection
- This represents lowest values obtained. Actual values for crystalline, especially polycrystalline materials, will be higher.