effects the size of surface smoothness at contact surfaces and the size of efficient interference. Surface smoothness is not applied to perfectly smooth surfaces. For those surfaces, the efficient interference equals the minimum interference and the maximum loading capacity.
Review of surface quality achieved by specific machining methods.
Roughness Average, Ra - micrometers [μm] (microinches [μin] )
|
50 |
25 |
12.5 |
6.3 |
3.2 |
1.6 |
0.8 |
0.4 |
0.2 |
0.1 |
0.05 |
0.025 |
0.0125 |
|
|
(2000) |
(1000) |
(500) |
(250) |
(125) |
(63) |
(32) |
(16) |
(8) |
(4) |
(2) |
(1) |
(0.5) |
|
|
Flame cutting |
- | + |
- |
||||||||||
|
Snagging |
- |
+ |
+ |
- |
|||||||||
|
Sawing |
- |
+ |
+ |
+ |
+ |
- |
|||||||
|
Planning, shaping |
- |
+ |
+ |
+ |
- |
- |
|||||||
|
Drilling |
- |
+ |
+ |
- |
|||||||||
|
Chemical milling |
- |
+ |
+ |
- |
|||||||||
|
Electric discharge |
- |
+/- |
+ |
- |
|||||||||
|
Milling |
- |
- |
+ |
+ |
+ |
- |
- |
||||||
|
Broaching |
- |
+ |
+ |
- |
|||||||||
|
Reaming |
- |
+ |
+ |
- |
|||||||||
|
Electron beam |
+ |
+ |
+ |
- |
- |
||||||||
|
Laser |
+ |
+ |
+ |
- |
- |
||||||||
|
Electro - chemical |
- |
- |
+ |
+ |
+ |
+ |
- |
- |
|||||
|
Boring, turning |
- |
- |
+ |
+ |
+ |
+ |
- |
- |
- |
- |
|||
|
Barrel finishing |
- |
- |
+ |
+ |
- |
- |
|||||||
|
Electrolytic grinding |
-/+ |
+ |
- |
||||||||||
|
Roller burnishing |
- |
+ |
- |
||||||||||
|
Grinding |
- |
- |
+ |
+ |
+ |
+ |
- |
- |
|||||
|
Honing |
- |
+ |
+ |
+ |
- |
- |
|||||||
|
Electro - polish |
- |
+ |
+ |
+ |
- |
- |
- |
||||||
|
Polishing |
- |
+ |
+ |
- |
- |
- |
|||||||
|
Lapping |
- |
+ |
+ |
- |
- |
- |
|||||||
|
Superfinishing |
- |
- |
+ |
+ |
+ |
- |
|||||||
|
Sand casting |
- |
+ |
- |
||||||||||
|
Hot rolling |
- |
+ |
- |
||||||||||
|
Forging |
- |
+ |
+ |
- |
|||||||||
|
Permanent mold casting |
- |
+ |
- |
||||||||||
|
Investment casting |
- |
+ |
- |
- |
|||||||||
|
Extruding |
- |
- |
+ |
+ |
- |
||||||||
|
Cold rolling, drawing |
- |
- |
+ |
+ |
- |
||||||||
|
Die casting |
- |
+ |
- |
Key:
+: Average application
- : Less frequent application
The ranges shown are typical of the processes listed.
Higher or lower values may be obtained under special conditions.