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6CCVD Research

Calibration of the spherical tip radius of Rockwell hardness diamond indenters using a confocal laser scanning microscope

At a Glance

Section titled ā€œAt a Glanceā€
MetadataDetails
Publication Date2024-08-14
JournalMeasurement Science and Technology
AuthorsMutaib Zackaria, AndrƩ Felgner, Febo Menelao, Thomas Ahbe, Uwe Brand
Citations1

Abstract

Section titled ā€œAbstractā€

Abstract The precise form of an indenter is an essential part of hardness testing methods. It is therefore incumbent upon a user to ensure that the indenter geometry is calibrated before performing a hardness test. A geometric change of the tip radius by Ā±5 Ī¼m can cause a change of approximately 0.6 units of Rockwell hardness C scale (HRC) in a material with a hardness of 65 HRC. Keeping in mind that the measurement uncertainty is typically of the order of 0.3 HRC, it is critical to know the true value of the tip radius. Typically, tactile methods are used to determine the tip radius of a Rockwell hardness diamond indenter from the measured surface topography. Two main drawbacks of tactile measurements are the long duration of measurement and the limitation in capturing surface features of sizes smaller than the probe tip radius of 2 Ī¼m. Both could be overcome by using an optical 3D measurement. Confocal laser scanning microscopes (CLSM) allow a fast contactless 3D-mapping of the surface of Rockwell hardness diamond indenters and can be used to obtain geometric information such as the tip radius. The accuracy of these 3D measurements is still under question. Within this work, some of the influencing factors for fast 3D surface measurement are investigated. Using a CLSM with a 50x objective lens and a numerical aperture of 0.95, typical shape deviations of Rockwell diamond indenters are shown. Furthermore, an improved 3D based point cloud method for the evaluation of the indenter radius is presented. The aim of this paper is to explore the capabilities and limits of CLSM to obtain the 3D surface of a Rockwell hardness diamond indenter in order to calibrate the tip radius and compare their results with measurements from traceable stylus instruments.

Tech Support

Section titled ā€œTech Supportā€

Original Source

Section titled ā€œOriginal Sourceā€

References

Section titled ā€œReferencesā€
  1. 2012 - The influence of geometrical tolerances of Vickers indenter on the accuracy of measured hardness [Crossref]
  2. 2000 - Progress in determination of the area function of indenters used for nanoindentation [Crossref]
  3. 2012 - Development of NIST standard reference meterial (SRM) Rockwell hardness diamond indenters
  4. 2008 - Correlation of the microdislocation parameters with the hardness of plastically deformed heat-resistant steels [Crossref]
  5. 1992 - An improved technique for determining hardness and elastic modulus using load and displacement sensing indentation experiments [Crossref]
  6. 1961 - Die in die Rockwell-HƤrteskalen eingehenden Fehler in Folge ungenauer PrĆ¼fkraft und die Form der Eindringkƶrper

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