|
|
The
surface quality and accuracy of the tolerance
is greatly influenced by the interaction
of the feed rate and corner radius. The
stability of the clamping system and the
machine are other decisive factors.
|
| General
recommendation: |
The surface quality can be improved
by using higher cutting speeds and possitive
rake angles.
Use a smaller corner radius if there
is a risk of vibration.
Especially high quality surfaces can
be achieved using uncoated hard metals
(sharper cutting edges than coated grades).
|
The
diagram shows theoretical Rmax
values for specific feed/corner radius
combinations.
 |
Theoretical
maximum roughness height (Rmax)
|
Rmax
= Roughness height
r = Corner radius
fn = Feed
(mm/dev) |
  |
|
|
Mean roughness figure (Ra)
Prosedure:
Look up the appropriate Rmax value in the
conversion table. Then read off the correct
combination of corner radius and feed rate..
Conversion table for various measurement
systems. This cannot be used to calculate
the mathematical relationship between the,
Rmax, ve Ra . |
Rmax
 |
|
Ra
= CLA = AA |
|
|
 |
|
| RMS |
|
|
|
|
values
for roughness |
|
1.6 |
0.30 |
11.8 |
0.33 |
13.1 |
|
|
1.8 |
0.35 |
13.8 |
0.39 |
15.3 |
|
|
2.0 |
0.40 |
15.7 |
0.44 |
17.4 |
N5 |
|
2.2 |
0.44 |
17.5 |
0.49 |
19.4 |
|
|
2.4 |
0.49 |
19.2 |
0.54 |
21.3 |
|
|
2.6 |
0.53 |
20.8 |
0.59 |
23.1 |
|
|
2.8 |
0.58 |
22.7 |
0.64 |
25.2 |
|
|
3.0 |
0.63 |
24.6 |
0.70 |
27.3 |
N6 |
|
3.5 |
0.71 |
27.8 |
0.79 |
30.9 |
|
|
4.0 |
0.80 |
31.4 |
0.89 |
34.8 |
|
|
4.5 |
0.90 |
35.2 |
1.0 |
39.1 |
|
|
5.0 |
0.99 |
38.8 |
1.1 |
43.1 |
|
|
6.0 |
1.2 |
47.2 |
1.3 |
52.4 |
N7 |
|
7.0 |
1.4 |
55.1 |
1.5 |
61.2 |
|
|
8.0 |
1.6 |
63.0 |
1.8 |
70.0 |
|
|
9.0 |
1.8 |
71 |
2.0 |
78.8 |
|
|
10.0 |
2.0 |
97 |
2.2 |
87.7 |
|
|
15.0 |
3.2 |
126 |
3.10 |
140 |
N8 |
|
20.0 |
4.4 |
173 |
4.9 |
192 |
|
|
25.0 |
5.8 |
238 |
6.4 |
264 |
|
|
27.0 |
6.3 |
247 |
7.0 |
274 |
N9 |
|
30.0 |
7.4 |
292 |
8.2 |
324 |
|
|
35.0 |
8.8 |
346 |
9.8 |
384 |
|
|
40.0 |
10.7 |
422 |
11.9 |
468 |
|
|
45.0 |
12.5 |
485 |
13.9 |
538 |
N10 |
|
50.0 |
14.0 |
552 |
15.5 |
613 |
|
|
Tools
and Indexible Inserts for TURNING
