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Type  Code  Determination  Determination Example (Figure) 

Arithmetical Mean Roughness 
Ra  Ra means the value obtained by the following formula and expressed in micrometer (µm) when sampling only the reference length from the roughness curve in the direction of the mean line, taking Xaxis in the direction of mean line and Yaxis in the direction of longitudinal magnification of this sampled part and the roughness curve is expressed by y=f(x): 

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).


TenPoint 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). 
Arithmetical Mean Roughness Ra 
Max. Height Rz 
TenPoint Mean Roughness RZJIS 
Sampling Length for Rz •RzJISI (mm) 
Conventional Finish Mark 


Standard Series  Cutoff Value c(mm) 
Standard Series  
0.012 a  0.08  0.05 s  0.05 z  0.08  
0.025 a  0.25  0.1 s  0.1 z  
0.05 a  0.2 s  0.2 z  0.25  
0.1 a  0.8  0.4 s  0.4 z  
0.2 a  0.8 s  0.8 z  0.8  
0.4 a  1.6 s  1.6 z  
0.8 a  3.2 s  3.2 z  
1.6 a  6.3 s  6.3 z  
3.2 a  2.5  12.5 s  12.5 z  2.5  
6.3 a  25 s  25 z  
12.5 a  8  50 s  50 z  
25 a  100 s  100 z  8  
50 a  200 s  200 z  –  
100 a    400 s  400 z   