Hardness test impression measurement in material surfaces - involves narrow light beam projected onto tested surface and moved across impression

摘要

A concentrated light beam is used. Its dia. at the point of incidence is small with respect to the surface area to be measured and it is directed vertically onto the tested surface. It is moved parallel to the surface so that the path of the light spot crosses at least once the test impression. The intensity of light reflected within a certain angle is measured. The intensity change of light at the impression edge crossing marks the beginning and end of the movement path section corresponding to the distance between edges of the impression. This length is measured.