Verfahren zur automatischen Bestimmung der Haerte durch Vermessen eines Pruefeindrucks

Verfahren zur automatischen Messung der Haerte nach Wickers. Der Pruefeindruck des Pruefkoerpers wird mit einer optischen Vergroesserungseinrichtung aufgenommen, wobei der Pruefeindruck derart beleuchtet wird, dass entweder der Rand gegenueber dem Umfeld hell erscheint oder der Haerteeindruck dunkel gegenueber dem Umfeld. Es wird dann die Kontur des Eindrucks in Form der Randpunkte erfasst, die zur Berechnung der Haerte der Probe notwendigen geometrischen Groessen aus dem Randpunkt ermittelt und daraus die Haerte berechnet.

DE 3401527 A UPAB: 19930925 Hardness is tested automatically using a pyramidal or ball indentation tool, a two-dimensional photograph of the indentation for conversion, and orientated illumination. The illumination is reflected from the sloping side of the indentation to display the edge of the indetation clearly against a surrounding field. Most of the contour of the indentation is recorded, its geometrical size is determined by computer, and the hardness derived. A point (1) on the indentation (10) formed in a Vickers hardness test is illuminated (8) and the reflected light is received at point (2) on a microscope (3), using a lens (4) with a telecentre aperture above its main plane (5). The distance between the aperture (6) and plane (5) equals the focal length of the lens (4). The aperture (6) admits only beams parallel to the optical axis. The incident light is at approx. 45 deg. to the optical axis (9). Points on the object which do not have the same slope as the Vickers indentation cannot therefore reflect light on to the image plane (3) and appear dark. USE/ADVANTAGE - Vickers or Brinell hardness measurement. Overcomes problems of distortion of indentation by grinding ridges on specimen surface. Eliminates human errors. 1/3