Glass polishing
Mechanical polishing.
Fluid jet polishing.
Fluid jet polishing of optical surfaces
Abrasive liquid jet as a flexible polishing tool
Experimental study on surface generation in optical glass with fluid jet polishing process
Chemical polishing: Heated bath of concentrated sulfuric acid (H₂SO₄) and hydrofluoric acid (HF).
Flame polishing.
Ion beam polishing.
Magneto-rheological finishing (MRF).
Elastic emission machining (EEM).
Ultrasonic polishing. Ultrasonic + cerium oxide. 20% to several times faster.
Laser polishing.
“It was determined that surface roughness on the 100-μm size scale was responsible for a loss in transparency. Surface roughness on the submicron size scale did not affect the transparency.”
Surface Finish Conversion Chart: Ra, RMS, Rz, and Typical Processes
| Ra (µin) | Ra (µm) | RMS (µin) | Rz (µm) | Grit # | Typical Process / Application |
|---|---|---|---|---|---|
| 250 | 6.30 | 275 | 25 | 60 | Standard machining, #1 finish (HRAP) |
| 71 | 1.80 | 78 | 7 | 80 | — |
| 52 | 1.32 | 58 | 5 | 120 | — |
| 42 | 1.06 | 46 | 4 | 150 | — |
| 19 – 32 | 0.48 – 0.80 | 21 – 33 | 1.9 – 3.2 | 180 – 220 | #4 brushed, dairy/sanitary range |
| 15 | 0.38 | 17 | 1.5 | 240 | ASME BPE SF4 (bio-pharma EP) |
| 12 | 0.30 | 14 | 1.2 | 320 | — |
| 9 | 0.23 | 10 | 0.9 | 400 | Fine lap, mirror prep |
| 4 | 0.10 | 4.4 | 0.4 | 500 | — |
| 2 | 0.05 | 2.2 | 0.2 | — | Optical / mirror finish |