TIME 3110 Surface Roughness Gauge

Surface roughness measurement,

Surface roughness is a variation in the material surface on a microscopic scale, it determines the visual effect of a surface, shiny or mat, and the friction of the material vs another surface sliding over it.
In a lot of cases the roughness determines the characteristics of the material or object. Things like the ability to form a seal when contacting another surface or the amount of heat and wear created from a bearing surface.
A smoother surface will also be less sensitive for dirt and bacteria growth and will therefore be easier to clean, this is important in food processing industries.
In other situation a minimum friction or higher adhesion is desired which requires a higher surface roughness.

To be able to compare the different surface roughness it is usually measured in Ra or Rz and will be calculated in µm or µin according to ISO 21920-2:2021
Measurements are usually made using a mechanical gauge or a laser scanner.

Ra provides the calculated average deviation of the surface from the mean value (value if the surface was perfectly flat) of the sampling area.
Rz provides the average of variation in height between the highs and lows of 5 lines within the sample surface area
Rt shows the maximum deviation between highs and lows within the sample surface area.
Sampling Length is the benchmark’s length used to determine its surface roughness.
Evaluation length is the total sample length required to determine the roughness of the material and may include more than one sample length.