Extracted from JIS B0601 (1994), JIS B0031 (1994)
■ Types of Surface Roughness
Parameters representing the surface roughness of industrial products are defined as arithmetic average roughness (Ra), maximum height (Ry), ten-point mean roughness (Rz), average irregularities spacing (Sm), mean spacing of local peaks (S), and load length rate (tp). The surface roughness is the arithmetic mean value of each part randomly extracted from the surface of the object.
[Center line average roughness (Ra75) is defined in the appendix of JIS B 0031 · JIS B 0601.]