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SURFACE ROUGHNESS
SURFACE ROUGHNESS
(From JIS B 0601-1994)
| Type | Code | Determination | Determination Example (Figure) |
|---|---|---|---|
| Arithmetical Mean Roughness | Ra | Ra means the value obtained by the following formula and expressed in micrometer (!m) when sampling only the reference length from the roughness curve in the direction of the mean line, taking X-axis in the direction of mean line and Y-axis in the direction of longitudinal magnification of this sampled part and the roughness curve is expressed by y=f(x):
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| Maximum Height | Rz | Rz shall be that only when the reference length is sampled from the roughness curve in the direction of the mean line, the distance between the top profile peak line and the bottom profile valley line on this sampled portion is measured in the longitudinal magnification direction of roughness curve and the obtained value is expressed in micrometer (μm).
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| Ten-Point Mean Roughness | RZJIS | RZJIS shall be that only when the reference length is sampled from the roughness curve in the direction of its mean line, the sum of the average value of absolute values of the heights of five highest profile peaks (Yp) and the depths of five deepest profile valleys (Yv) measured in the vertical magnification direction from the mean line of this sampled portion and this sum is expressed in micrometer (μm).
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RELATIONSHIP BETWEEN ARITHMETICAL MEAN (Ra) AND CONVENTIONAL DESIGNATION
(REFERENCE DATA)
(REFERENCE DATA)
| Arithmetical Mean Roughness Ra |
Max. Height Rz |
Ten-Point Mean Roughness RZJIS |
Sampling Length for Rz • RZJIS I (mm) |
Conventional Finish Mark | |
|---|---|---|---|---|---|
| Standard Series | Cutoff Value λc (mm) |
Serie Estandar | |||
| 0.012a | 0.08 | 0.05s | 0.05z | 0.08 |  |
| 0.025a | 0.25 | 0.1s | 0.1z | ||
| 0.05a | 0.2s | 0.2z | 0.25 | ||
| 0.1a | 0.8 | 0.4s | 0.4z | ||
| 0.2a | 0.8s | 0.8z | 0.8 | ||
| 0.4a | 1.6s | 1.6z | |
||
| 0.8a | 3.2s | 3.2z | |||
| 1.6a | 6.3s | 6.3z | |||
| 3.2a | 2.5 | 12.5s | 12.5z | 2.5 | |
| 6.3a | 25s | 25z | |||
| 12.5a | 8 | 50s | 50z | |
|
| 25a | 100s | 100z | 8 | ||
| 50a | 200s | 200z | - | ||
| 100a | - | 400s | 400z | - | |
*The correlation among the three is shown for convenience and is not exact.
*Ra : The evaluation length of Rz and RzJIS is the cutoff value and sampling length multiplied by 5, respectively.
*Ra : The evaluation length of Rz and RzJIS is the cutoff value and sampling length multiplied by 5, respectively.
