The cleanliness of the room where measurements are performed is another important condition when it comes to ensuring precise measurements. If dust or dirt in the air gets inside the measuring instrument, the instrument’s moving parts may be damaged. Also, foreign matter may interfere with accurate measurements if any gets between the measurement target and the measuring instrument.
The types of foreign matter found at production sites include grains of sand and metal chips generated during processing, as well as fibres from work clothes and hair. These types of foreign matter may result in errors at the sub-micrometre level or higher, so it is necessary to ensure that the environment is cleaned on a daily basis.