The following table contains the expected surface roughness (range) associated with various machining methods.
| Machining Method | Surface Roughness Range μm (μins) |
|---|---|
| Super-finishing | 0.05>0.2 (2>8) |
| Lapping | 0.05>0.4 (2>16) |
| Honing | 0.1>0.8 (4>32) |
| Cylindrical grinding | 0.1>1.6 (4>63) |
| Diamond turning | 0.1>1.6 (4>63) |
| Surface grinding | 0.1>1.6 (4>63) |
| Broaching | 0.8>3.1 (32>125) |
| Reaming | 0.8>3.1 (32>125) |
| Boring and Turning | 0.4>6.3 (16>250) |
| Die Casting | 0.8>1.6 (32>63) |
| Extruding | 0.8>3.1 (32>125) |
| Cold Rolling and Drawing | 0.8>3.1 (32>125) |
| Milling | 0.8>6.3 (32>250) |
| Drilling | 1.6>6.3 (63>250) |
| Planing and Shaping | 1.6>12.5 (63>500) |
| Sawing | 1.6>25 (63>1000) |
| Forging | 3.1>12.5 (125>500) |
| Sand Casting | 12.5>25 (500>1000) |
| Flame Cutting and Hot Rolling | 12.5>25 (500>1000) |
The above ranges reflect the surface finish that can be achieved using normal production machines based upon historical experience.
However, with modern machinery, correct speeds and feeds and properly prepared cutting tools, the above surface finishes can be significantly improved.
Conversely, incorrect machining procedures may produce poorer results.
You will find further reading on this subject in reference publications(2)