VDI 3400 Surface Finishes Definition, VDI 3400 Depth
VDI 3400 Surface Finish – is a scale often used by German machine manufacturers and quite widely used in Spark and Wire Erosion (Verein Deutscher Ingenieure, the Society of German Engineers)
- Charmilles EDM surface finish chart
- EDM surface finishes chart
- Charmille EDM finish
- Charmilles texture
- Charmilles finish
- EDM Sparking surface finish
|
EDM Surface Finish Scale |
RA MICRO-METER |
RA MICRO INCHES |
RMS |
|
-2 |
.08 |
3.14 |
3.90 |
|
-1 |
.09 |
3.54 |
4.40 |
|
0 |
.10 |
3.94 |
4.90 |
|
1 |
.11 |
4.33 |
5.50 |
|
2 |
.12 |
4.72 |
5.90 |
|
3 |
.14 |
5.51 |
6.90 |
|
4 |
.16 |
6.29 |
7.90 |
|
5 |
.18 |
7.09 |
8.90 |
|
6 |
.20 |
7.87 |
9.90 |
|
7 |
.22 |
8.66 |
10.80 |
|
8 |
.25 |
9.84 |
12.3 |
|
9 |
.28 |
11.02 |
13.80 |
|
10 |
.32 |
12.60 |
15.80 |
|
11 |
.35 |
13.78 |
17.20 |
|
12 |
.40 |
15.60 |
19.50 |
|
13 |
.45 |
17.6 |
22.00 |
|
14 |
.50 |
19.60 |
24.50 |
|
15 |
.56 |
21.60 |
27.00 |
|
16 |
.64 |
25.00 |
31.30 |
|
17 |
.72 |
28.10 |
35.20 |
|
18 |
.80 |
31.20 |
39.00 |
|
19 |
.91 |
35.50 |
44.40 |
|
20 |
1.01 |
39.40 |
49.30 |
|
21 |
1.12 |
43.70 |
54.60 |
|
22 |
1.28 |
49.90 |
62.40 |
|
23 |
1.44 |
56.20 |
70.30 |
|
24 |
1.60 |
62.40 |
78.00 |
|
25 |
1.81 |
70.60 |
88.20 |
|
26 |
2.03 |
79.10 |
98.90 |
|
27 |
2.24 |
87.40 |
109.20 |
|
28 |
2.54 |
99.10 |
123.90 |
|
29 |
2.84 |
110.80 |
138.50 |
|
30 |
3.15 |
122.9 |
153.70 |
|
31 |
3.6 |
140.40 |
175.50 |
|
32 |
4.05 |
158.00 |
197.50 |
|
33 |
4.50 |
175.50 |
218.80 |
|
34 |
5.10 |
198.90 |
248.60 |
|
35 |
5.70 |
222.30 |
277.90 |
|
36 |
6.30 |
245.70 |
306.20 |
Measurement of surface finishes is done with instruments called profilometers. Experience proves that measurement of surface finishes by comparison using a surface finish gauge does not give an error above 2 CH classes. The criteria of roughness are the Ra (Europe) – CLA (UK) – AA (USA) To obtain a grading of roughness, Charmilles has defined a CH scale, which is however cross referenced with the standards that are in common use.
Definition of Roughness criteria
No CH = 20 log (10 Ra) (µm)
Some significant rules and figures
1 µm Ra = CH20
10 µm Ra = CH40 If Ra = Ra x 2 CH = CH+6 ex: 1 µm Ra = CH20
- µm Ra = CH26
- µm Ra = CH32
The ratio
between 2 successive CH units is 1.12
The difference
between 2 successive CH units is 12.2%
The MAX Rt: roughly equal to 8 x Ra
The mean Rt: is the arithmetic mean of the 5 Max Rt recorded on the 5 sample lengths selected.
(For establishing the technology: 0.8mm)
Mean Rt = 5 x the Ra value
Note:
In surface finish measurements a tolerance of + 2 CH units is accepted.
Further note:
The American and English standards admit the following relationship between the values V(RMS) and V(Ra):
V(RMS) = 1.11 V(Ra)
The French standard NF 05051 is tied in with the ISO 1302 standard concerning classes of surface finish.
Please contact with : info@Upmold.com for more informations or helps
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