Converting surface roughness units between standards
| Ra (um) | Rz (um) | RMS (uin) | Process |
|---|---|---|---|
| 0.1 | 0.8 | 4 | Mirror polish |
| 0.2 | 1.6 | 8 | Fine grinding, lapping |
| 0.4 | 3.2 | 16 | Precision grinding |
| 0.8 | 6.3 | 32 | Finish machining |
| 1.6 | 12.5 | 63 | General machining |
| 3.2 | 25 | 125 | Rough machining |