TESA Roughness gauges
Mean roughness Ra (ISO 4287, DIN 4768) The mean roughness Ra matches the arithmetical mean of the absolute values related to the profile deviation y within the reference length l. Max. profile valley depth Rmax (DIN 4768) The max. profile valley depth Rmax is for the most significant single roughness depth Zi within the total length lm. According to ISO 4288 and DIN 4287 - Part 1, this parameter is also specified as Ry max. Mean roughness depth Rz DIN (DIN 4768) The mean roughness depth Rz is the arithmetical mean of single roughness depths of successive sampling lengths le. According to ISO 4287 and DIN 4762, the parameter Rz DIN is also specified as Ry5. Since Rz changes its name in both DIN 4768 and ISO 4287, this parameter is also specified as Rz DIN or Rz ISO. If the parameter Rz is measured according to DIN, it is generally admitted that the extreme value specified by ISO is matched providing that Rz ISO does not exceed Rz DIN.