Particles from the base material, which dissolve during cleaning from the test object, but which were not originally adhering particulate pollution.
Examples: decomposition of the material, sealing material, alternating ridges and coatings.
Possible causes: the use of inappropriate chemicals for cleaning, procedures for cleaning and cleaning parameters, material removal by mechanical friction in the cleaning container.
Applied particles: particles that are applied to the test object.
Examples: Improper handling, contamination by environmental influences.
Possible causes: Contaminated gloves or gloves made of unsuitable material, use of contaminated transport containers, improper packaging and storage.
Particles that are removed from the test object.
Examples: Improper handling, removal of pollution caused by environmental influences.
Possible causes: removal or falling of particles in the handling, improper packaging (eg, particles remain in the packaging bag) and storage of the test object (particles are removed by an air current).
Particles that are not detached from the test object and thus not recorded as particle contamination.
Examples: Bound chips, which are not detected and removed from the test personnel. Particles, which from inaccessible parts of the workpiece (eg water jacket area of cylinder heads), could not be resolved.
The occurrence of the above events can not be excluded and quantitatively not reproducible. The above disturbances are an element of uncertainty regarding the statement of the exact value cleanliness.