Standardisation
A comprehensive range of standards defines the requirements to be met by the devices, the measuring technique and the capturing of the roughness parameters. The international ISO standardization has gained importance towards the German DIN standards.
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Overview of new standards
Already published:
- ISO 3274 Instruments, stylus tips, c / s ratio
- ISO 4287 Parameter
- ISO 4288 Evaluation length
- ISO 11562 Gaussian filter
- ISO 12085 Motif
- ISO 13565 Rk
In preparation:
- ISO 5436 Standard
- ISO 12179 Instrument calibration
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Relation between old and new parameters
| DIN |
ISO |
| |
R Roughness |
P Profile |
W Waviness |
| Rt |
Rt |
Pt |
Wt |
| RmDIN |
Rz1max |
Pz1max |
Wz1max |
| RzDIN |
Rz, Rz4,Rz3,Rz2,Rz1 |
Pz |
Wz, Wz4,Wz3,Wz2,Wz1 |
| Ra |
Ra |
Pz4,Pz3,Pz2,Pz1 |
Wa |
| Rp |
Rp |
Pa |
... |
| Rpm |
Rp1max |
... |
|
| Rq |
Rq |
... |
|
| Rpk |
.... |
|
| Rk |
Rk |
.... |
|
| Sm |
RSm |
|
|
| Sk |
Rsk |
|
|
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Do the measuring results change?
The PTB has examined the effects that the ISO standardization, agreed in 1997, has on the measurement of the roughness parameters. Only slight differences have been detected for PTB roughness parameters.
- PTB examination no basic modifications
- s / 2 µm stylus tips effects neutralize each other in part
|
Roughness standards
|
Rz [µm]
|
Difference old-new
|
| Fine |
1,4 |
-2,3 % |
| Middle |
2,9 |
-1,6 % |
| Rough |
8,6 |
-0,7 % |
| Very rough |
13,2 |
-3,1 % |
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Stylus tips
In some cases the new ISO standars require finer stylus tips.
- 2 µ or 5 µm radius
- highest quality
- available for all HOMMEL-ETAMIC surface pick-ups
- stylus tip measurement as an option
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Filter
A new feature is the short-wave limitation of the roughness signal. The connection to the filter settings known until now is shown in ISO 3274:1997
| [mm] |
s [µm] |
c/s |
Stylus tip radius [µm] |
| 0.08 |
2,5 |
30 |
2 |
| 0,25 |
2,5 |
100 |
2 |
| 0,8 |
2,5 |
300 |
2 oder 5 |
| 2,5 |
8 |
300 |
5 |
| 8 |
25 |
300 |
10 |
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